April 2002 Troubleshooting Professional Magazine_ Automotive Cooling System Maintenance and Repair

10/4/2014 April 2002 Troubleshooting Professional Magazine: Automotive Cooling System Maintenance and Repair

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Troubleshooters.Com Presents

Troubleshooting Professional Magazine

Volume 6 Issue 4, April 2002

Automotive Cooling System Maintenance and RepairCopyright (C) 2001 by Steve Litt. All rights reserved. Materials from guest authors copyrighted by them and licensed for perpetual use to Troubleshooting

Professional Magazine. All rights reserved to the copyright holder, except for items specifically marked otherwise (certain free software source code,GNU/GPL, etc.). All material herein provided "As-Is". User assumes all risk and responsibility for any outcome.

[ Troubleshooters.Com | Back Issues | Automotive Troubleshooting ]

Steve Litt is the author of Troubleshooting Techniques of the Successful Technologist and Rapid Learning: Secret Weapon of the Successful Technologist.

A stitch in time saves nine -- Poor Richard's Almanac (Ben Franklin)

CONTENTS

Editor's Desk

Upcoming Automotive Troubleshooting Book

Disclaimer and DisclosureHow Cooling Systems Work

Cost of an Overheat

Anatomy of an Overheat

Preventive Maintenance of Cooling Systems

Optimizing Overheating DiagnosisCoolants 101

Do It Yourself Coolant Changes

Life After Windows: Nothing New to Report

Linux Log: You Just Might Like Linux

Letters to the Editor

How to Submit an Article

Trademarks

URLs Mentioned in this Issue

Editor's Desk

By Steve Litt

Two years have passed since I published "Litt's Overheating Hypothesis". During those two years many

Troubleshooters.Com visitors have emailed stories of cyclical overheating and once-per-drive overheating that

http://www.troubleshooters.com/troubleshooters.htm

http://www.troubleshooters.com/troubleshooters.htm

http://www.troubleshooters.com/tpromag/archive.htm

http://www.troubleshooters.com/tautomot.htm

http://www.troubleshooters.com/bookstore/ttech.htm

http://www.troubleshooters.com/bookstore/rl.htm



were accompanied by detectable combustion gasses in the coolant, and were cured by head gasket replacement.

As far as I'm concerned, these emails prove the hypothesis beyond a reasonable doubt.

Those two years also brought bushels of email containing voluminous information about automotive cooling

systems. I've learned a lot in the past two years, and I'd like to share some of that knowledge with you.

This issue of Troubleshooting Professional Magazine explores the details of automotive cooling systems -- how

they work, how to maintain them, and how to diagnose them. This issue serves three audiences:

1. Professional Auto Technicians

2. Do it yourself mechanics

3. Car owners needing a second opinion

Many professional Auto Technicians already know everything in this issue, but it's surprising how many don't.

Almost every day I receive an email from someone whose auto shop failed miserably in diagnosing the cause of

overheating, resulting in hundreds of dollars needless expenditure. The Auto Technician too proud to at leastread this issue is an Auto Tech you might want to stay away from.

And that's why this issue of Troubleshooting Professional is so important to car owners. If your local shop

doesn't understand the role of a broken head gasket as a cause of overheating, or the fact that such a brokenhead gasket might not exhibit the classic symptoms of steam out the exhaust or white/yellow foam/gunk on the oil

cap, you probably want to look for a different shop. Also, the car owner needs to understand the cost ofoverheats (often exceeding $2000.00), and the fact that the single most important protection against overheats ispreventive maintenance.

The do it yourself mechanic will appreciate the diagnostic and preventive maintenance information in thismagazine. This information will eliminate most unnecessary parts purchases and unneeded labor by enabling moreaccurate diagnosis.

So if you fix cars for a living, fix your own car, or just own a car, kick back, enjoy, and profit from this magazine.

Steve Litt is the author of "Troubleshooting Techniques of the Successful Technologist". Steve can be reached at SteveLitt's email address.

Upcoming Automotive Troubleshooting Book

By Steve Litt

I'm considering writing a book called "Automotive Troubleshooting", which applies the Universal

Troubleshooting Process to auto repair. It will focus on the Universal Troubleshooting Process, using automotiveexamples. It won't contain detailed automotive information -- you can already get that in a Chilton manual or themanufacturer's service manual, or hundreds of other books. The unique contribution of this book would be the

consistant application of the Universal Troubleshooting Process.

Do you think this is a good idea for a book? What information would you like to see in the book, and howwould you like to see it presented? Do you have any suggestions?


http://www.troubleshooters.com/email_steve_litt.htm



Steve Litt is the author of Rapid Learning: Secret Weapon of the Successful Technologist. He can be reached at Steve Litt'semail address.

Disclaimer and Disclosure

By Steve Litt

Disclaimer

The information on in this document is information is presented "as is", without warranty of any kind, eitherexpressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a

particular purpose. the entire risk as to the quality and performance of the information is with you. Should thisinformation prove defective, you assume the cost of all necessary servicing, repair, correction or medical care.

In no event unless required by applicable law or agreed to in writing will the copyright holder, authors, or any

other party who may modify and/or redistribute the information, be liable to you for damages, including anygeneral, special, incidental or consequential damages or personal injury arising out of the use or inability to use

the information, even if such holder or other party has been advised of the possibility of such damages.

Disclosure

I am not a mechanic, nor even a particularly mechanically inclined car owner. My primary place in automotive

Troubleshooting is reporting of symptoms and conducting tests. The limits of my automotive mechanical work arereplacement of batteries, and rare minor tuneups infrequent thermostat replacement. My knowledge of specific

cars extends only to those I've owned, and my wife's car.

The information you see in this document is my opinion, based on personal experience, experiences reported byTroubleshooters.Com visitors, and research. It wouldn't surprise me to find that some of the information in this

document is erroneous. If you choose to use this document's information, you should use it in addition toinformation from other sources.

Apology

There was a time this type of disclaimer would have seemed absurd, but today lawyers rule the land. Now withUCITA rearing its ugly head, failure of an electronic author to absolve himself of all responsibility can bedisastrous. To the 99.9% of you who take responsibilities for your own actions and earn your money through

hard work rather than lawsuits, I apologize for the necessity of this disclaimer.

Safety Notice

CAUTION! Safety first. Be extremely careful when looking into or putting your hands or any other body part

into your engine compartment. Use safety glasses. Keep all body parts away from open carburetor or air intake

-- assume it will backfire. Backfires can produce blindness and/or third degree burns. Keep long hair VERY

securely pinned up, remove all jewelry, do not wear loose clothing while working on a car. Heed these warnings





even when the car is not running. Remember, modern cars have electric fans that can turn on at any time.

Be careful not to short the battery -- battery explosions can throw potentially burning/blinding acid. Don't openthe radiator cap of an overheated car. When it's cool enough to open, use a rag to block any spray, and open

very slowly. Wear hard shoes capable of shielding impact from a dropped part.

Take proper precautions when jacking up a car so the jack doesn't "kick out". A "kicked out" jack can be everybit as destructive as a kick from a large horse. Block the wheels, put on the brakes, seat the jack properly.

Never crawl under a jacked up car unless it has been properly blocked up and completely secured. Even then,

remember that earthquakes, sudden wind and drunk driver impacts happen. A professional lift is always best.

The preceding warnings are by no means an exhaustive list of the risks encountered when working on a car.

Always use common sense. You assume full and complete responsibility for the use of the information on this

page.

This isn't just theory. An old skating buddy lost a finger when his wedding ring was grabbed by a fan belt. I met a

guy at MacDonalds who spent 2 weeks in the hospital when an open-carb backfire caused third degree burns

over most of his forarm. Skin graft city. Imagine if his face had been by that carb. We've all read about peoplewho crawled under a jacked up car and got crushed.

Be very careful, or else do not work on cars.


How Cooling Systems Work

By Steve Litt

The cooling system has one and only one purpose -- to remove excess heat from your engine. As your engine

burns gasoline, a little less than a third of the released energy goes into mechanical energy to run your car. The

rest is converted to heat. Some of that heat is blown straight out the tailpipe, while the rest heats the engine itself.

Without a cooling system, the engine would be destroyed by heat within 3 to 30 minutes of startup.

The cooling system works by moving coolant (water plus antifreeze) through the engine, and moving that heated

coolant through the radiator, where its heat is transferred to the surrounding air. The cooling system must haveenough cooling capacity to cool a car ascending a long, steep mountain road, where the driver might have the gas

pedal 2/3 of the way to the floor.

But it must be regulated in such a way that at a steady 40 MPH on a flat road in subzero weather, the engine'stemperature is allowed to quickly rise to the manufacturer's recommended temperature (usually about 200

Farenheit, give or take 20 degrees). That recommended temperature should also be maintained when the car

goes up a 10 mile 7% grade in 100 degree weather. Such regulation is accomplished by the car's thermostat -- a

heat sensitive valve that allows coolant to flow through the radiator at high temperatures, but cuts off that flow atlow temperatures.





The water pump sucks cooled coolant from the radiator and pushes it into the engine. The coolant flows through

the engine, absorbing the engine's heat. If the thermostat is open, that coolant then flows into the radiator for

cooling. As it flows through the radiator, it heats the tubes and fins on the radiator, and that heat is transferred tothe air flowing through the radiator. At low speeds that air flow is maintained by the fan, and at high speeds it's

maintained by the relative velocity of the vehicle in relation to the outside air.

Meanwhile, a parallel path brings hot coolant from the engine through the heater in the passenger compartment,and back into the water pump. That path is controlled by the heater valve, which in turn is controled by the lever

or electronic climate control on the dashboard. The parallel path is not restricted by the thermostat, so

passengers get heat even when the thermostat is closed. However, some cars have a mechanism which shuts off

coolant through the heater during an overheat, I guess on the theory that you want to maximize flow through theradiator by shutting off the heater. While such a theory might be credible when the cause of overheating is low

coolant, it prevents the alert driver from turning on the heater full blast and thereby letting the heater act as a

second radiator. Perhaps such a shutoff is a safety feature so there's no way overly pressurized coolant can

rupture the heater and spray on the passengers. So if you've had symptom where "the car overheats and then theheater blows cold air", the heater probably has been shut off due to overheat.

The entire system is sealed with one exception. The radiator cap contains a spring which maintains a constantpressure by venting coolant (to the reservoir tank) when pressure rises above its specified value -- typically

around 15 PSI. It's normal for some coolant to vent in this way, which is why the reservoir is more full when the

car is hot than when it's cold. The radiator cap also allows the vacuum created when the system cools to "suck

back" coolant from the reservoir. But in the case of an extreme overheat, vented coolant overflows the reservoir,thereby creating a low-coolant situation and making the overheat even worse.

Looking at the diagram, you see that oil, gasoline, combustion gasses and coolant all flow inside the engine.

These materials are kept separate by the head gasket(s). A breached or broken head gasket, or a bent head,allows any or several of these materials to mix. Coolant into the cylinders produces huge clouds of white exhaust

(steam) out the tailpipe. Coolant into the oil produces a yellow/white foam or gunk on the oil cap, as well as

degrading the oil, possibly past the point of lubricating usefulness. Combustion gasses leaking from the cylinder to

the coolant might produce no obvious symptom, but it's an extremely dangerous condition, because it can causean overheat by any one or more of four different mechanisms:

1. By forcing excessive coolant out the reservoir, thereby creating a low-coolant situation

2. By forming a gas bubble around the thermostat's sensor, thereby preventing the thermostat from opening3. By heating the coolant to such a degree that the radiator cannot dispense all the heat

4. By breaking down the coolant's corrosion protection, thereby damaging the water pump or radiator,

ultimately causing overheating



It's possible for a broken head gasket to allow combustion gasses into the coolant, without allowing coolant into

the cylinders or coolant into the oil or oil into the coolant. In such a situation, the broken head gasket could

silently cause overheats. The definitive test for this type of head gasket problem is to test for combustion gassesat both the radiator fill pipe and at the reservoir.

Excess Cooling Capacity

Automotive cooling systems must have HUGE levels of excess cooling capacity. Next time you drive 60 mph ona flat deserted road, notice how far you push on the gas pedal. Probably a millimeter to a centimeter. Now see

how much you need to push the gas pedal to ascend a 6% grade at 45mph. Probably an inch or two. Go up to

65 and on some cars you'll be near flooring it. 1/3 of all that gasoline is consumed heating the engine.

Your cooling system must be able to get rid of all that heat. Difficult enough, it becomes even more of a challenge

if the air temperature is warm (less heat transfer from radiator to air), and brutal if your car is heavily loaded or

towing something. If the heat generated by combustion significantly exceeds the cooling capacity, you'll severelyoverheat quickly (typically after a mile or two of climbing).

A well functioning cooling system has the capacity to maintain the engine at under 100 degrees temperature

during continuous 50mph level drives on cool days. But of course the temperature needs to be 160-230Fahrenheit, depending on the car (consult your owners manual). That means in most driving situations the cooling

capacity must be partially defeated. This is accomplished by the thermostat, which acts as a deliberate

bottleneck, regulating the amount of cooling to keep the temperature at a proper level. A somewhat typical

thermostat would be closed until 180 Fahrenheit, after which it would open further as the temperature increases,until at 195 it's completely open. This means that in the 15 degrees between 180 and 195, the cooling capacity

would go from 0 to the full capacity of the system (enough to scoot up a long 6% grade at 65 mph carrying 5

people in a well designed and maintained machine). Below is a graph showing how temperature increases with

increased engine heat production (i.e., more gas):

The portion in blue represents a level of heat production so small that it can be disbursed by the direct contact of

the engine with ambient air. In practice this might be achieved in the case of a 40mph wind blowing into the open

hood of a car idling in the deep of a northern Minnesota winter's night, but otherwise this condition is never seen

in real life. An idling engine, and certainly driving, at anything resembling normal conditions requires radiator

cooling.

NOTE: Don't make the mistake of thinking the preceding diagram represents temperature versus time. While that graphwould look similar at the leftmost part of the graph, that's not what's being represented. You can think of the precedingdiagram as a graph of various driving conditions, each maintained for 10 minutes or more.



The violet portion represents heat production levels within the regulated cooling capacity of the cooling system.

The slight temperature gain across this range is due to the fact that the thermostat opens slowly and steadily overa range of about 15 degrees Fahrenheit. This is the normal operating range of the vehicle. Once the engine is

warmed up, all driving should be done in this range.

The red portion represents a heat production level beyond the cooling capacity of the cooling system. The

temperature goes sky high. On a well maintained vehicle, you would expect the red portion only when the car is

used beyond its design capabilities, like using a compact car to pull a trailer up a long 6% grade.

The bottom line is that on a well maintained vehicle, the bottleneck, by a huge margin, is the thermostat. Contrast

that with a vehicle with a compromised cooling system not capable of cooling a hard worked engine, or in

extreme cases even a lightly worked engine:

Here there's no regulation. The entire graph is basically a straight line. Moderate hard usage sends the car into

the red. The operating temperature of a vehicle in this state of repair would vary widely with ambient temperature

and length of time driving. Typically no "normal operating temperature" can be identified for a vehicle in thiscondition. Such a vehicle will almost certainly experience a catastrophic overheat the first time the driver takes a

lengthy drive, or drives in hot weather, or drives up a moderate hill.

The controlling bottleneck of this vehicle is not the thermostat -- it's something else in the cooling system. The

automotive technician's task is to find that bottleneck.


Cost of an Overheat

By Steve Litt

This article is written primarily for the car owner. Professional Auto Techs know this information all too well, and

most do it yourself mechanics know it also. Anyone not knowing this information leaves himself vulnerable to

making some very bad decisions that will cost a great deal of time and money.

Sometimes you get lucky and an overheat can be corrected by fixing its root cause. But all to often, overheating -- even a single 3 minute incident -- can cause consequential damage that costs thousands to fix. An overheat is a

very bad thing.





The most common consequential damage is a broken head gasket. This happens when the head and blockexpand differently than the head gasket, or even worse, when an aluminum head and a cast iron block expand at

radically different rates, breaking the head gasket. Bimetal engines, whether they be aluminum heads on a cast

iron block, or cast iron heads on an aluminum block, are likely to break head gaskets with the slightest overheat.

Unfortunately, replacing head gaskets is a big job requiring hours for even an experienced mechanic with all the

right tools. For a do it yourselfer, it could be prohibitively time consuming or even impossible. As a result, the

cost of replacing a head gasket ranges from $500.00 to $2500.00, depending on the make and model, and

whether the heads must be machined.

Broken head gaskets result from a moderate overheat, or even a mild overheat on a bimetalic engine. A more

serious overheat can bend or break the heads. Now you have a large parts cost to add to the huge labor charge

for replacing the head gasket(s). New heads cost hundreds, and machining heads is also costly.

Some folks consider continuing to drive the car with a broken head gasket. That's a very bad idea if you want to

keep the car more than a year. Combustion gas in the coolant can easily cause even more severe overheats, plus

it can quickly cancel the anti-corrosion properties of your antifreeze, leaving you open to corrosion, leaks, andblockages, all of which result in further overheating. If coolant gets into the oil, the oil's lubricating ability is

compromised, leading to engine seizes, bearing freezes, and all sorts of other problems. If coolant gets into the

cylinders it can cause a broken starter, solenoid, or flywheel. Broken head gaskets often make the car run

poorly, and often make it a gross polluter, which can be costly indeed in states that enforce smog regulations.

Your engine was designed to operate at a certain temperature. When it operates colder than that, emissions go

up, efficiency goes down, and engine wear increases. This is why cars don't drive as well cold as they do whenthey're "warmed up". On the opposite end, cars operating hotter than designed, even at temperatures lower than

what it would take to break a head gasket on a cast iron block/head combination, risk pre-ignition/detonation

caused by too-high engine temperature. Such pre-ignition/detonation can damage various components in your

engine. If you've ever driven a seriously overheated car you know it sounds much different, and it doesn't sound

good.

But what if you're one of these wild and crazy guys who doesn't shut down the car even when the temperature

gauge is pinned, there are huge clouds of steam coming out the hood, and the car has started running funny. You,my friend, will most likely need a new engine. Extremely overheated engines seize, freeze, warp, and who knows

what else. Engines aren't too expensive, but the labor is prohibitive, and all too often the new engine lasts 10,000

miles and then blows up.

Added to those costs is the cost of having an unreliable vehicle. Cars that overheat once tend to overheat often;

unless an unusually competent and comprehensive repair job is done. Overheats results in a tow charges, missed

work, and even hazards to personal safety. It's doubtful anyone's personnel record lists "broken head gasket" asa cause for job termination, but it just might list "excessive absence" and "unreliability".

I hope I've gotten your attention. A single overheat can cost you thousands. You need to know that, because

during the rest of this magazine I'll be recommending preventive maintenance that costs nearly $100.00 per year,

and diagnostic procedures which cost almost $100.00 not counting the actual fix. When evaluating the cost of my

suggestions you must realize the cost of the alternatives -- $1500.00 to fix a head gasket, $300.00 for a new

radiator installed, and if you go to an incompetant Automotive Technician who practices diagnosis by serial

replacement, you'll spend even more.



When viewed alongside the alternatives, $100.00/year to keep your cooling system healthy starts sounding

downright cheap.


Anatomy of an Overheat

By Steve Litt

In the simplest possible terms, any overheat must be caused by one of these five causes:

1. Grossly malfunctioning engine

2. Using the vehicle beyond its capabilities

3. Inadequate cooling system

4. Low coolant level

5. Inability to adequately transfer heat

Grossly malfunctioning engine

This almost never happens. In order to produce enough heat to overload a well functioning cooling system, the

car would need to be in such bad shape that going 55 MPH would require pressing half way down on the gas. A

car this mistuned would have many more symptoms. Sometimes a grossly mistuned or damaged engine combineswith a compromised cooling system to cause an overheat, but it's extremely rare that the primary cause of an

overheat is a malfunctioning engine.

NOTE:

Considerable documentation on the web and in other places states that anoverly lean fuel mixture can cause overheating, so you might want tocheck your mixture. That being said, I can tell you that my 1973 FordCountry Squire ran incredibly lean (former owner's smog workaround)and yet did not overheat.

Using the vehicle beyond its capabilities

This is pretty obvious. If you tow a heavy trailer cross country using a little truck with a small six cylinder engine,

you're using the vehicle beyond its capabilities and should not be surprised if it overheats. If you expect to dohauling and towing, at the least you need a radiator designed to dissapate the heat generated by an engine hauling

a load up a mountain road.

Inadequate cooling system

Many cars are manufactured with cooling systems barely capable of cooling them in extreme conditions. If such avehicle goes up a 10 mile stretch of 6% grade when it's 100 farenheit outside, it's likely to overheat. If a car with





little excess cooling capacity is driven in stop and go traffic on hot days with the air conditioning on full blast, it's

likely to overheat. If a relatively new car overheats in challenging conditions but not straight 40 MPH drives on

60 degree days, it just might have been manufactured with insufficient excess cooling capacity.

In addition, many used cars have insufficient cooling capacity because somebody cut corners when replacing a

radiator. I once bought a Dodge Coronet with a radiator salvaged from a Dodge Dart. On hot days the slightest

hill would overheat it. I had a radiator shop make and install a huge custom 4 row and it no longer overheated.

Some used cars lack cooling capacity because the fan shroud has been removed. Such cars tend to overheatmore at idle and low speed.

If you've proven to a reasonable degree that the car's cooling system, as manufactured, is insufficient to cool the

car during extremely challenging driving, see if you can install a higher capacity radiator. Install the highest

capacity radiator you can purchase or have manufactured.

NOTE:

When replacing a radiator, it's best to use a similar type of radiator, butbigger. For instance, if the original radiator was aluminum, it's best tomake the new radiator aluminum. Try to replace plastic radiators withbigger plastic radiators. If you need to use a different type replacement,be aware that you might need to change the type of antifreeze you use.

Low coolant level

Low coolant level is a more common overheating cause than grossly malfunctioning engines, usage beyond

capabilities, and inadequate cooling systems combined. If coolant gets seriously low, cooling capacity is

compromised and the engine overheats, either in challenging circumstances or sometimes in all circumstances.

When researching low coolant it's important to discover where the coolant is going. It's either leaving through the

radiator cap or reservoir, or it's not. In either case, there are various mechanisms:

Coolant leaving SOMEWHERE BESIDES through reservoir or radiator capExternal leak

Internal leak

Coolant leaving through reservoir or radiator cap

A breached head gasket allowing combustion gas into the coolant, thus pushing the coolant out the

reservoir.

A bad radiator cap allowing coolant out the reservoir (or occasionally right out the cap).

An existing overheat venting excessive coolant into the reservoir, overflowing the reservoir. Notethe coolant could be in vapor form.

External Leak Not Involving the Reservoir or Radiator Cap

A pressure test can prove leakage other than out the reservoir or radiator cap. By replacing the radiator cap with

the pressure tester, large pressures can be put into a completely closed cooling system. If the system holds

pressure, there's no leak. If it doesn't hold pressure, there's a leak, at which time your job is to find it. If the leak



is to the outside of the engine (and most are), you should see coolant dripping. Then you need to follow its trail.

If you can't see well enought to follow its trail, you can put ultraviolet sensitive dye into the coolant, hang an

ultraviolet lamp (a black light) in the engine compartment, and see the river of luminescent coolant. Typical sites

of external leaks are:

Hoses

Radiator

Water pump (especially at the drain hole)Freeze plugs

Heater core (coolant smell inside passenger compartment, possibly puddles on floor of passenger seat)

Drain plug on engine

Drain petcock on radiator

Note that in the case of the heater core, a pressure test might not reveal that leak because the heater valve may

be shut. Let the engine run til it's hot (but nowhere near overheat), and with all the car doors shut and thewindows closed, turn the heater on full blast and carefully sniff around the passenger seat and the floor of the

passenger seat (wear eye protection and be careful not to get sprayed with hot coolant). If you smell coolant,

suspect a leaking heater core. If you see a puddle of coolant on the floor, suspect a leaking heater core. Also, be

sure to visually inspect the heater hoses under the hood while the car is hot (but not overheated) and the heater is

on full blast. If you see a leak in a heater hose, that's at least one source of your leak.

Internal Leak Not Involving the Reservoir or Radiator Cap

If the cooling system fails the pressure test but no leak is observed and no coolant falls to the ground, it's possibly

an internal leak through a breached head gasket or a breach in the separation between the radiator and the

transmission fluid cooler. Such a leak would typically be one of these three:

Coolant through the head gasket into the cylinders

Coolant through the head gasket into the oil

Coolant through the radiator into the transmission fluid

Voluminous white smoke out the exhaust, especially when starting, indicates coolant into the cylinders. Yellow or

white foam or gunk on the oil cap indicates coolant into the oil, as does beads of water in the oil or a water film.

Thankfully, water into the transmission fluid is rare. If the transmission fluid on the transmission dipstick looks

good, coolant into the transmission fluid is probably not the problem.

Breached head gasket: combustion gas in the coolant pushing coolant out thereservoir

This is best detected with a combustion gas detection test, using either a smog sniffer or a block tester. There are

different kinds of block testers, one of which is from NAPA and costs in the neighborhood of $45.00.

Bad radiator cap allowing coolant out the reservoir or cap

Observe the cap for cracks (in rubber or in metal) or swelling. Put your thumb on the base and fingers on the topof the cap and squeeze. If it's easy to squeeze, the radiator cap is bad and will probably lose coolant.



Existing overheat venting excess coolant through the reservoir

If the cooling system passes its pressure test, there's no evidence of a heater core or heater hose leak, the

radiator cap is good, the block test indicates there is no combustion gas in the coolant, and there's no evidenceof coolant in the oil, cylinders or transmission fluid, it's best to assume that the coolant loss was due to an

overheat caused by something other than coolant loss. In that case, investigate the possibility of grossly

malfunctioning engine, using the vehicle beyond its capabilities, and inadequate cooling system. All three areunusual. If it's none of those, treat this as an inability to adequately transfer heat.

Catastrophic Coolant Loss

If the upper or lower radiator hose breaks, or if the radiator ruptures, the car will be drained of coolant within

seconds, and the temperature will rise precipitously. If such a car is not shut down within a minute of such acatastrophic coolant loss, a blown engine is the likely result. If you ever see smoke or steam coming out the hood

while driving, pull over safely and shut it down instantly. Don't wait for the the next exit -- it's likely your enginewill be ruined by then. Towing is expensive, but it's much cheaper than replacing an engine.

Inability to transfer heat

If a pressure test shows the root cause not to be a leak, and if the cause is not a grossly malfunctioning engine,usage beyond design, or weakly designed cooling system, then the problem is caused by an inability toadequately transfer heat. Now is the time to look for the cause of overheating within the closed system of your

cooling system.

Here are some of the mechanisms of inadequate heat transfer:

Circulation stopped by collapsed lower hoseCirculation slowed and heat transfer retarded by excessive deposits in radiatorThermostat always closed, or opens at higher than specified temperature

Coolant not able to absorb and carry heatInadequate air flow through radiator

Blockage in upper radiator hose (highly unlikely)Insufficient water pump pressure

Blockages in water pathways within the engine block

Circulation stopped by collapsed lower hose



As you can see from the preceding diagram, the water pump sucks water out of the radiator through the lowerradiator hose, and shoots it into the engine block. That suction would cause the lower radiator hose to collapse if

it weren't for the fact that a sturdy spring inside the lower hose prevents such collapse. A collapsed lower hosewould prevent circulation through the radiator and quickly cause an overheat.

So with the car running and warmed up (but not overheated), visually inspect the hose and make sure it's not

collapsed. With the car not running and the engine cool, feel the hose and make sure it's incompressible with yourfingers. Also make sure it's not cracked or brittle.

SAFETY WARNING: When feeling hoses or in any way reaching into the engine compartment, wear eyeprotection and take reasonable precautions to prevent getting burned. Never allow your fingers, hands, hair,

clothing, or other body part to come near the fan or belts. Remember that electric fans can suddenly turn on evenif the car is not running and the key is not in the ignition.

Although a collapsed bottom hose would cause an overheat, it's possible that a massive radiator blockagecaused the collapsed hose. If you see a collapsed hose and it appears to have been the correct hose (i.e. it has a

spring but the spring failed), look very carefully for blockages in the radiator. Whatever the cause of the collapse,replace any bottom radiator hose that has ever collapsed, and be sure to fix whatever caused the collapse.

Circulation slowed and heat transfer retarded by excessive deposits in radiator

Radiator deposits and corrosion lead to blockage and overheat. In fact, many coolant losses and head gasketfailures start out as simple radiator blockages. Detecting radiator deposits starts with the customer's symptom

description. If the car's stable temperature has been slowly rising for weeks or months, radiator deposits are onepossible cause. If the car ran at a specific temperature, then all of a sudden jumped to a higher temperature,radiator deposits aren't a likely cause. As in all deductions based on symptom descriptions, you must evaluate

the customer's ability to relate the facts as they happened.

Most radiator deposits serious enough to push the temperature anywhere near redline are visually observable if

you drain a few inches of coolant from the radiator. Other diagnostic tests include using an infrared temperaturesensor to detect "hot spots" in a radiator. Such hot spots indicate places that are cooling efficiently (the hot

coolant is flowing through them), as opposed to the "cool spots" that have no coolant.

Steve Litt's Radiator Opinions

In my personal opinion, a radiator with enough corrosion or deposits to make it a likely cause (not THE likelycause, just A likely cause) of overheating, should be replaced with a higher capacity radiator. The preceding

sentence assumes that the customer wants to keep the car. Before the customer can decide whether he wants tokeep the car, the customer needs to know whether there's a head gasket problem, so a block test, visualinspection of the car's exhaust, visual inspection of the transmission's dipstick, visual inspection of the oilcap, and

a pressure test should all be performed to determine the likelyhood of a broken head gasket.

You noticed I said replace the radiator, not "rod it out". I'm of the opinion that oftentimes "rodding out" does not

cure the problem, and in many other instances it cures the problem for only a few months. "Rodding out" is laborintensive and not cheap. The extra money spent on a brand new radiator is money well spent in my opinion.



And in my opinion, there's no such thing as too much radiator. Get the biggest one you can. A huge radiator can,

in some cases, compensate for suboptimal conditions:

Long, steep grades100+ degree weather

Accidentally running with too little coolantTowing

Small head gasket breach (at least for a short while)Severely mistuned or misrepaired engine

Missing fan shroud

When I say "a huge radiator", area counts more than thickness. I'd much rather have a 24x16 two row than a12x16 four row, but certainly all other things being equal, a four row is better than a two row. When getting huge

radiators keep in mind that when the radiator extends beyond the area that can be ventilated by the grill, thebenefits of big area are decreased.

If you're a car owner, upon hearing that your current radiator is seriously corroded, deposited or plugged, I'dadvise getting the biggest possible radiator. If you need to spend extra money to have a huge radiator

manufactured, that's a good idea, assuming you have confidence in the outfit doing the manufacturing.

NOTE:

When replacing a radiator, it's best to use a similar type of radiator, butbigger. For instance, if the original radiator was aluminum, it's best tomake the new radiator aluminum. Try to replace plastic radiators withbigger plastic radiators. If you need to use a different type replacement,be aware that you might need to change the type of antifreeze you use.

If you're an Automotive Technician, try to get your customer to see the value in a huge, brand new radiator.

Thermostat always closed, or opens at higher than specified temperatures

If the thermostat remains closed at all times, no coolant will enter the radiator, and the engine will overheat. If thethermostat opens only at an excessively high temperature, the engine will remain at that temperature, and if that

temperature is hot enough to cause coolant loss, additional overheating will result.

You can deduce when a thermostat opens by a number of means, including feeling for pressure changes on theupper hose, or viewing water flow through the radiator. SUCH VIEWING SHOULD BE DONE IN A SAFE

WAY -- warm but not hot, eye protection, do not lean over the radiator.

Once you can determine the opening and closing of the thermostat, measuring the engine temperature with a

thermometer can tell you the opening temperature. I've never measured the temperature this way. Manytechniques exist, but I can't vouch for any particular techniques.

Thermostats typically malfunction by one of two mechanisms:



Thermostat cannot sense water temperature because of a gas bubbleDefective thermostat

Perhaps the easiest way to rule out all thermostat problems is to run without a thermostat for an hour or so. Ifoverheating ceases, your thermostat is involved in one way or another. If overheating continues (but perhapstaking longer to happen), the thermostat is ruled out as a cause. If the thermostat appears to be at fault, you

might try putting it in a pot of hot water and see if it opens at the correct temperature. If it does, the thermostat isprobably not defective, meaning that you might have a gas bubble problem.

NOTE: Running without a thermostat is a diagnostic test, not a solution. To reduce the risk of engine damage,"thermostatless" operation should occur for the minimum time necessary to reproduce an overheat, or confirm

that the overheat does not occur in the absence of a thermostat.

Many people have successfully cured gas bubble problems by drilling a 1/8" hole in the thermostat. This hole lets

the gas rise past the thermostat, allowing the thermostat's wax temperature sensor to once again contact coolant.However, it's possible that such a hole could cause some problems, so you might want to weigh that possibility.

Here are the instructions one Troubleshooters.Com visitor, A.S.E. certified master truck and auto mechanicDennis Buler, gave me for drilling the 1/8" hole:

Top view of thermostat. The violet dot at the 12 o'clock position of the rim is whereDennis recommends drilling the 1/8" hole.

Side view of thermostat

Bottom view of thermostat

Dennis' exact words were "i drill the hole in the flat disk part like half way between where the gasket would sealand the center opening mechanism".



One more thing. Remember that a gas bubble can be caused by combustion gasses passed through a head

gasket breach. In such a case it's likely you'll need to replace your head gasket.

Coolant not able to absorb and carry heat

When I was younger and less wise, I drained the cooling system of my 1973 Ford Country Squire and replacedit with 100% ethylene glycol (antifreeze). The car overheated badly. 100% ethylene glycol is a poor absorber of

heat. 100% propylene glycol is a somewhat better absorber of heat, and in some cases is useful as a coolant. Butit doesn't absorb as much heat as 50/50.

At temperatures below the boiling point of water, water is more effective at absorbing and carrying heat than any

mixture of water and either ethylene glycol or propylene glycol. If you have a 160 degree thermostat and yourcooling system is functioning well, you could theoretically add cooling capacity by replacing your water/antifreeze

mixture with pure water.

But the added cooling capacity would be short lived indeed. Adding antifreeze gives the following benefits that

water alone cannot:

Higher boiling temperature at a given pressureLower freezing temperature

Corrosion resistance

You need coolant capable of absorbing and carrying heat. Pure ethylene glycol is not such a coolant. Pure

propylene glycol is barely adequate. Pure water will absorb and carry heat very well, but if your engine isdesigned to run hot, your water will boil away, causing an overheat. Additionally, pure water will lead to acracked block in cold climates, and excessive cooling system corrosion in any climate.

Always know what you're using for coolant. If you know there's no propylene glycol in the coolant mixture, youcan use a simple specific gravity indicator to deduce your mixture. The ideal mixture is 50/50, but in extremely

cold climates you can get by with 70% antifreeze and 30% water. Any more antifreeze will lead to overheating.

If there's a likelihood that some or all of your coolant is propylene glycol, specific gravity measurements will not

accurately indicate your mixture. Use a refractometer instead.

If the coolant is so old that the driver does not know what all is in it, perhaps it's time to flush the cooling systemand replace it with whatever the car's manufacturer recommends. Coolant is discussed in more detail later in this

magazine.

Inadequate air flow through radiator

No matter how well heat is transferred to the radiator, unless the radiator is cooled by air flow, the coolingsystem will not function. At moderate and high driving speeds, air is forced through the radiator as the car pushesthrough the air. At idle and low driving speeds, a fan is required to ventilate the radiator with cool air. Therefore,

when a symptom description mentions overheating at low speed, idle, or stop and go traffic, the fan systemshould be investigated first.



The Fan System

There are mechanical fan systems and electrical fan systems. Transverse engines have electrical fan systemsbecause of the difficulty of having a belt turn a right angle to operate a front-facing fan. Electrical fan systems are

comprised of a fan attached to the radiator (on the engine side), and electronics to turn the fan on and off asneeded. If the electronics malfunction such that the fan never comes on, overheats at slow and idle will be theresult. If that's suspected, there are ways to jumper the fan so it's always on. Be sure to check electrical diagrams

so as not to inadvertently damage the fan control electronics. If the jumpered fan runs and the overheat goesaway, the problem is in the electronics or in whatever senses the temperature. If the fan doesn't run even after

jumpering it directly across the battery, the fan is defective. Either way, jumpering the fan is a temporarydiagnostic test, not a solution. Immediately fix the root cause -- don't continue to use a car with a jumpered fan.

Most cars with forward facing engines use a mechanical fan system, consisting of the fan, fan clutch, fan belt, and

radiator shroud. On such a system the fan belt turns the fan clutch, which turns the fan, which pulls air through theradiator, constrained by the radiator shroud.

If the fanbelt slips, it can't deliver necessary torque to drive the fan at sufficient speed, and idle/low speedoverheating can result. The fan clutch is designed to deliver more torque at higher temperatures. If it doesn't

function right, it doesn't transmit enough torque to drive the fan at sufficient speed, and idle/low speedoverheating can result. The fan shroud is like a tunnel between the fan and the radiator, ensuring that all air pulledby the fan comes through the radiator, instead of simply being sucked from the surrounding area or around from

the back of the fan. Without a fan shroud, idle and low speed overheating is likely to occur.

You might wonder why a fan shroud is necessary on a mechanical fan when it's not necessary on an electrical

fan. An electrical fan is mounted to the radiator itself. It's very close to the radiator, and moves with the radiator.Contrast this with the mechanical fan, which must be mounted several inches away from the radiator. Because

the mechanical fan moves with the engine, and not with the radiator, installing the mechanical fan close enough toeliminate the need for the fan shroud would cause the fan to gouge the radiator when extreme engine torquecauses the engine to move. This is especially true when a motor mount is broken.

Other impediments to cool air through the radiator

Other impediments to cool air through the radiator can cause overheating at all driving speeds. One suchimpediment is the air conditioning cooling coils, which typically sit right in front of the radiator. Obviously, the airconditioning coils restrict the flow of air to the radiator, but more important, if the air conditioner is on, the air

conditioning coils get very hot, heating the air intended to cool the radiator. It's like driving on a 120 degree day.Add to that the fact that air conditioner consumes power that must be provided by burning more gasoline, and it

becomes obvious why you should turn off your air conditioner during mountain travel.

Bugs, dirt and debris can clog the air flow passages of your radiator, or of the air conditioner cooling coils beforethe radiator. Either way, airflow is restricted, and overheating can result. There are methods of cleaning the

radiator and cooling coils, but be very careful not to damage the delicate tubes and vains. Also, these areas areoften difficult to access. Sometimes compressed air is the best way to clean them. Once cleaned, you might want

to install a "bug catching net" in your grill, especially in climates where there are numerous flying bugs.

Radiators are typically constructed with tiny tubes soldered to fins, or else oval tubes. Either way, the idea is to



allow air to flow through the radiator. If these things become bent, air flow is impeded. Bent tubes and fins canbe straightened, but trying to do so can also further damage the radiator or cause a leak. Radiators should behandled delicately.

Another impediment to air flow is a damaged radiator. Vains and tubes are bent and twisted by crashes and

mishandling of the radiator by inept technicians. Another cause of radiator damage is fan damage, in which amechanical fan hits the radiator. The primary cause of fan damage is a bad motor mount, so always maintain your

motor mounts.

In general, you might deduce impediments to cool air by observation, or lacking that by seeing how well

compressed air goes from the outside of the grill to the area between the radiator and the engine. On my 1988Buick Park Avenue with air conditioning, when I put the blowing end of a 5HP industrial vacuum on the grill, Icould feel the breeze on my hand inside the engine compartment, but just barely. If you have an easy way of

removing your grill, perhaps the best and quickest test is to investigate is visually. Even if the air conditioningcooling coils block your view of the radiator, it's a good bet that if the air conditioning coils are clean, so is the

radiator.

A complete radiator investication involves removal of the radiator, which is labor intensive and should only bedone when there's good reason to strongly suspect dirt on the radiator or bending of the radiator's components.

Blockage in upper radiator hose (highly unlikely)

This is so unlikely that it should be tested only in cases of unexplained overheating. The test might be to let the

car cool, then disconnect the upper radiator hose from the radiator, at which time you'd lose coolant. If thereappears to be a blockage, replace the hose. Once again, this is highly unlikely.

Another extreme unlikelihood is that the water pump is pushing flow backward, so that there's suction on the

upper hose. This could conceivably happen if a water pump made for a serpentine belt is used with a belt off thecrankshaft, or vice versa. Reversed pump direction would likely cause other strange symptoms.

Insufficient water pump pressure

If the water pump can't circulate the coolant, the car will overheat. Not only that, but the pressure and flow must

be sufficient to support high velocities through the radiator. It's important that the coolant experience turbulancein the radiator tubes, so that all the hot water contacts the tubes. Turbulance can occur only when coolantvelocities are above a certain level.

That being said, the water pump's job is to circulate coolant through a well functioning system, not to brute forcecoolant through a radiator whose tubes are clogged with deposits. There's no easy and accurate way to assess

the level of water pump functioning. Here are some things that can go wrong with a water pump.

Bad belt or wrong tensionBad bearings

Undersized or oversized pulleyBad impellers

Belt tension can quickly be checked by hand. Bad bearings can often be deduced by manipulating the water



pump shaft to determine whether there is play. Further confirmation can be had by loosening the belt driving the

water pump, and seeing if the pump turns reasonably free. Be careful not to stretch the belt -- loosen acomponent, do not strongarm the belt off the pulley.

An undersized or oversized pulley can be deduced by obtaining the manufacturer's documentation, or bycomparing the pulley to what the manufacturer put in similar cars. Be sure the similar car is similar enough. For

instance, if your water pump is driven by a serpentine belt, make sure you compare it to a similar model and yearwith a serpentine belt. An oversized pulley causes the pump to turn too slowly, thus reducing coolant flow,

possibly to the point of overheat. Note that theoretically the overheat should be speed independent because highspeeds require faster coolant flow. But that's just theory.

One might think that an undersized pulley would cause the pump to spin faster, thereby increasing coolant flow.

While this may be true for a moderately undersized pulley, if the pulley is significantly undersized it's just as likelyto present so much torque, and so little traction area, that the belt will slip, causing a vast decrease in coolant

flow -- probably at high speeds where coolant flow is most crucial.

Blockages in water pathways within the engine block

This is very hard to determine without partially disassembling the engine. For this reason the best way to "rule

out" blockages is to find a different cause. Luckily such blockages are usually localized and may not harm theengine excessively. Moderately quick diagnostic techniques that are at least a little useful include using an infrared

thermometer to try to find "hotspots" on the engine, and removing spark plugs to see if any show symptoms ofexcessive heat.

Because internal blockages in the engine block or heads are so hard to diagnose, it's best if they never happen.Practicing corrosion protection and impurity protection is probably your best defense.

Root Cause Drilldown

So far this article has explained most common mechanisms by which an overheat can occur. But thesemechanisms also have root causes, and an understanding of these ultimate root causes is essential forconstructing an economical preventive maintenance plan and for constructing economical diagnostic procedures.

This section discusses four lower level causes, as well as their ultimate causes and effects. Those three lowerlevel causes are:

CorrosionBreached head gasketRadiator damage

Normal wear and tear

Corrosion

Corrosion can cause the following overheating mechanisms:

Radiator leaks



Radiator deposits and blockages

Heater core leaksHeater blockagesHose deterioration (through electrolysis, in conjunction with heat, age and vibration)

Head gasket breachesWater pump failures

Thermostat failuresEngine "hot spots"

As you can see, preventing corrosion goes a long way toward preventing overheats.

Corrosion happens when the coolant loses its anticorrosive properties. With standard antifreeze in a 50/50mixture this happens in about 2 years or 24,000 to 30,000 miles. Same with 50/50 propylene glycol or 100%

propylene glycol. There are several "extended life" antifreezes. Some, such as the GM "Dex-Cool" complientantifreezes (Texaco/Havoline Dex-Cool and Prestone Extended Life 5/150), are designed to go 5 years or

150,000 miles between changes. Many new GM cars come from the factory with this type of coolant. However,"long life" coolants often revert to 2 years when mixed with other types of coolants, or when used in a system

with trapped air or rust/corrosion. Mixing antifreezes is generally a bad idea, and certain combinations canactually promote corrosion.

Furthermore, encroachment of combustion gasses into the coolant via a head gasket breach can neutralize any

coolant's corrosion inhibition long before the specified life.

Most antifreeze is extremely cheap. My local Discount Auto Center sells Prestone brand Ethylene Glycol

standard antifreeze for $6.99 a gallon, and Havoline Dex-Cool for the same price. You can get 3 gallons of highquality ethylene glycol antifreeze for $21.00. Propylene glycol is less likely to poison animals and is a little morecostly, as are the various more exotic antifreezes. In my opinion, it's time flush and change your antifreeze when:

You see any rust in your antifreeze, and it's been over 4 months since your last coolant replacementCorrosion or deposits are detected in your radiator, and it's been over 6 months since your last coolant

replacementDifferent types of antifreezes have been mixed

The cooling system needs service or diagnosis and the exact type and mixture of the coolant is unknownYour cooling system needs service requiring a major draining of coolantSomebody has used a "leak seal" type of product in the cooling system (these are usually temporary

stopgap measures, and often clog passages and components leading to further problems).

I personally believe that unless you know for certain that your cooling system is in perfect shape and always has

been, you should flush and change your coolant yearly. It's such a low price for preventing corrosion. Ipersonally believe that if you're using a 5 year/150,000 mile coolant, it's best to change it every 3 years or90,000 miles once the car is out of warranty. If you have reason to believe there's air, gasses, impurities,

deposits or rust in the coolant, 2 year or 1 year intervals might be even better.

While we're on the subject of economics of corrosion protection, distilled water is just too cheap not to use,

assuming you're a car owner doing your own work. Distilled water costs about $0.70 per gallon, so for about$2.00 per year you can give the anticorrosives in your antifreeze a fighting chance by not introducing calcium,

lime or who knows what into your cooling system. This is especially important if your antifreeze uses phosphates



as a corrosion inhibiter, because phosphates react with calcium to produce radiator-clogging scale. Naturally, ifyou find yourself low on coolant and need to get home, use tapwater. Never use softened water, as it contains

salts that can quickly corrode your cooling system.

If you can conquer the corrosion monster, you're most of the way to making sure your car never has a singleincident of overheating.

Breached Head Gasket

A breached head gasket can cause the following:

Overheating

Loss of coolant, with or without overheatingCorrosion of the cooling system

Destruction of the oil's lubricating propertiesBreakage of the starter, solinoid or flywheel

The most common cause of breached head gaskets are overheats. Even a single overheating incident can break ahead gasket, especially in a car with a bimetalic engine. The best way to protect against an overheat is to takeproper care of your cooling system, and to look at your temperature gauge often. If your car has an idiot light

instead of a temperature gauge, installing an aftermarket temperature gauge is an excellent investment.

Radiator Damage

Radiator damage retards proper air flow through the radiator, thereby causing or contributing to overheating.Also, radiator damage can cause leaks, either immediately following the damage, or months or years later. Here

are some ways to lessen the chance of radiator damage:

When doing your own work, handle the radiator like the fragile piece it isUse only competant automotive technicians

Don't crash your car, and if you do, replace a damaged radiator before it can cause overheatingCheck motor mounts frequently, and replace them when they break

A broken motor mount can allow the fan to rip through the radiator. Typical causes of premature failure of motormounts are aggressive driving and bad shocks.

Normal Wear and Tear

Things wear out. Many of those things can cause overheats if they break. As we've seen, even one overheat canseverely damage a car. Many of the components that can cause overheat when they wear out are cheap. They

should be replaced in a preventive maintenance program:

BeltsHoses

Hose clampsThermostat



Radiator cap

Coolant

By replacing these cheap and easy components on a regular schedule of preventive maintenance, you limit thelikelihood of damaging expensive parts such as the radiator, water pump, head gasket, heads, or engine.

Summary

This article discussed the common mechanisms by which an overheat occurs, and discussed root causes of manyof those mechanisms. As this article strongly implies, the best way to avoid overheats is by a program of

preventive maintenance.


Preventive Maintenance of Cooling Systems

By Steve Litt

As you can imagine from the preceding article, cooling system preventive maintenance can make the difference

between a reliable car with few problems, or a lemon with huge yearly shop costs. If you figure the yearly coolingsystem preventive maintenance costs $100.00, and you drive 10,000 miles per year, you're spending a penny a

mile to keep your. If the two year maintenance costs another $100.00, that adds a half a cent a mile. And if thethree year maintenance costs $150.00, that adds another half penny. So for two cents a mile you can keep your

car overheat free for a good long time.

The sad thing is that most people won't spend the money. Two cents per mile doesn't sound like much, but whenyou spend it all at once, and when you're spending it on a car that seems perfectly healthy, many folks feel it

doesn't make much sense. If you're an automotive tech, your job is to explain why it does make sense. Explainthat the customer's car may only seem healthy. Cooling system problems are a disease with a long incubation

period. It can take 4 years for radiator corrosion and deposits to reach the point where they compromiseeveryday driving.

But once the symptoms appear, they're often relentless. That clogged radiator, if not replaced in time, can lead to

a head-gasket busting catastrophic overheat. And if the head gasket isn't diagnosed correctly, replacing theradiator doesn't completely eliminate the symptom. The customer begins to believe his car is possessed by the

overheating demon.

The radiator isn't the only component being compromised. Old coolant corrodes the water pump, leading to

failure. And you know how replacement water pumps are -- they're seldom as good as the original, so after thefirst replacement, water pumps become a regular maintenance item at a couple hundred a pop.

An undiscovered bad hose can break, and unless the car's driver has the sense to safely pull over and shut it

down immediately, the head gasket will be breached.

Check your motor mounts often. A broken motor mount can allow a mechanical fan to slice into the radiator.





This can render the vehicle undriveable, or it can simply reduce the excess cooling capacity to the point where

the vehicle will overheat in challenging driving conditions.

Preventive maintenance can't necessarily prevent all these problems, but it can usually postpone most of them

until well past the car's first decade, and such preventive maintenance makes it likely that any cooling systemproblems will be caught before heads or head gaskets are damaged.

This article contains an example of a cooling system preventive maintenance program. I'd imagine it costs abouttwo cents a mile, and will probably enable the cooling system to be problem free for its first decade, and limit

problems to minor repairs thereafter.

If I ran an automotive shop, I'd package the yearly, two year and three year maintenance items for a fixed price,and sell them to customers as peace of mind. It takes a little education, but it's worth it in dollars and cents and in

customer goodwill. Note that much of this maintenance overlaps other maintenance, such as oil and lube and

transmission, so it could be combined with those. Finally, by keeping track of the customer's maintenance, theshop can provide a valuable service to customers with better things to remember than exactly when they lastreplaced their thermostat or belts. Also, by providing that service, the shop can maximize the likelihood that thecustomer will use the shop for all work, and not grind for the lowest price.

Troubleshooters.Com Suggested Yearly Preventive Maintenance(or every 15,000 miles, whichever's first)

This looks like a lot, but most of it is easy inspection. Because of the nature of the 2 and 3 year maintenanceitems, these inspection items are unlikely to uncover problems after the first yearly inspection. The only parts

involved in the yearly maintenance are the radiator cap and the coolant.

Bounce test the shocks (to insure protection motor mounts)Inspect belts for wear and tensionCheck function of serpentine tensioner armInspect hoses for excessive mushiness, excessive hardness, brittleness or cracking. By feeling from the

outside, inspect hoses for internal gaps that might indicate electrolytic breakdown. Also inspect hoses forevidence of leaks.Inspect inside of radiator for corrosion and to verify reasonable coolant flow.To the extent possible without extensive labor, inspect exterior of radiator and air conditioner cooling coils

for dirt and damage. Clean as necessary.Inspect water pump for leaks and excessive shaft play or bindingRevv test the motor mounts (to insure protection of radiator in a mechanical fan system)Verify that the engine maintains a temperature within manufacturer's specificationVerify that the thermostat is opening and closing at approximately the right temperature

Verify that the temperature gauge is reasonably accurateVerify that the electrical fan turns on at the right temperature, orVerify that the mechanical fan spins and its fan clutch is in good working orderVerify proper heater functionVerify the absense of white or yellow foam or gunk on the oilcap

Verify the absense of steam in the exhaust, especially on startup



Verify clean and pure transmission fluidVerify clean and pure coolant with no rust or other impuritiesPerform a pressure test

Replace Radiator CapThoroughly backflush and replace the coolant (or else drain radiator and replace with new coolant twiceyearly)

Troubleshooters.Com Suggested Every Two Years PreventiveMaintenance (or every 30,000 miles, whichever's first)

I'd imagine thermostat replacement plus testing for combustion gas could be done for less than $100.00. As longas high quality thermostats are used, I'm of the opinion that this would make thermostat failures almost obsolete,and it would hopefully detect bad head gaskets long before they contributed to the destruction of other

components. Given the yearly maintenance, it's doubtful that combustion gas would be found.

Test for combustion gas in the coolantReplace the thermostat

Troubleshooters.Com Suggested Every Three Years PreventiveMaintenance (or every 45,000 miles, whichever's first)

Unless a driver is very well informed, a broken water pump belt or a broken radiator hose will lead to acatastrophic overheat. Even if the customer seems intelligent enough to safely pull over and shut down upon firstdetection of a cooling problem, all sorts of teenagers might be driving the car. Unless the car is shut down within

a minute or so of the dropped belt or ruptured hose, severe engine damage will result. The money saved bytrying to extend belt and hose life past three years isn't worth the problems that result if the life estimate provestoo optimistic.

Replace any belts that have not been replaced in the past 2 years

Replace top and bottom radiator hoses that have not been replaced in the past 2 years


Optimizing Overheating Diagnosis

By Steve Litt

As the webmaster of Troubleshooters.Com, I've gotten dozens of letters that go something like this:

My car overheated , so I took it to the shop. They replaced the thermostat. I drove it for a few days and it

overheated again. They then charged me another $200 to replace the water pump, but as soon as I got the car

home it overheated so badly that it wouldn't even start. This time they rodded out the radiator for $150, and it





got better, but still overheated. So they charged me another $200 to replace the radiator with a new one (andtold me they were giving me a break on the price). That improved the situation even more, but it still overheatson long trips, and it runs rough and there's a lot of white smoke coming out the exhaust. When I took it back tothe shop they said it was a broken head gasket, and it would cost $1200 to fix. What do I do?

It's entirely likely that the original root cause was the radiator, and nothing but the radiator. But during the timeconsumed by diagnosis by serial replacement, successive overheats broke the head gasket, thereby adding yet anew overheating cause. Or take the case of an even less competant shop:

My car overheated, so I took it to the shop. They replaced the thermostat, but it still overheated. They thencharged me another $200 to replace the water pump, but nothing changed. So they replaced the radiator, but

everything was still as bad. Yesterday I took it to another shop, who told me the white foam on the oil cap andsteam coming out the exhaust indicates a broken head gasket, which was caused by all the overheating. Andthey told me I have a collapsed lower radiator hose, which probably caused the original overheating, and thatthe cost to install a replacement hose would have been $50. Could this be true?

Diagnosis by serial replacement is NOT an option if you want to have a profitable shop over the long term.Although some components are hard to test (water pumps, for instance), enough easy tests are available that youcan usually pinpoint the root cause if you do all the simple tests. Another reason to do a full scale diagnosticworkup is that by the time you see a typical overheat, multiple causes may be at work.

The following outline lists and categorizes relatively cheap and simple tests that will maximize the probability ofaccurately identifying the root cause, thus preventing costly and credibility busting diagnosis by serialreplacement:

Symptom description

When did the overheating start?Was the onset of overheating gradual or sudden?What situations tend to make the overheating worse?Does it happen more at idle, low speeds or stop and go traffic? (suspect fan system)How long does it take to overheat?

Has the overheating ever caused the car to stall? (suspect head gasket as a consequential damage)Does the engine temperature tend to go up and down as you drive? (suspect head gasket as acause)Does it overheat once, and then return to normal for the rest of the drive? (suspect head gasket as a

cause)Have you seen puddles of liquid where you've parked? (suspect leak)How long do you go between cooling system flushes (if never, suspect corrosion)Do you see steam? Where does it seem to come from?Describe anything you've seen, heard or smelled.

Do you have any other observations you think might have anything to do with this overheating?Symptom reproduction

Compare engine temperature with manufacturer's spec when running car according to customer'sdescription of the symptom's reproduction sequence



Verify that the temperature gauge is reasonably accurateVerify other specifics of the symptom description

Evaluate Head Gasket FunctionVerify the absense of white or yellow foam or gunk on the oilcapVerify the absense of steam in the exhaust, especially on startup

Verify clean and pure transmission fluidVerify clean and pure coolant with no oil, rust or other impuritiesTest for combustion gas in coolant at radiator fill pipe and at reservoir

Did coolant loss cause overheat, or did overheat cause coolant loss?Perform a pressure test, locate any leaks

Observe and test radiator capEvaluate fan system

Ask customer whether it tends to overheat more at idle, slow speeds, or stop and go trafficVerify that the electrical fan turns on at the right temperature, or

Verify that the mechanical fan spins and its fan clutch is in good working orderCheck fan belt driving mechanical fan

Research fanbelt related causesInspect belts for wear and proper tensionCheck function of serpentine tensioner arm

Radiator, water pump and thermostatInspect water pump for leaks and excessive shaft play or bindingTo the extent possible without extensive labor, inspect exterior of radiator and air conditionercooling coils for dirt and damage. Clean as necessary.

Inspect inside of radiator for corrosion and to verify reasonable coolant flow.Verify that the thermostat is opening and closing at approximately the right temperature

Both by pressure increase in top hose, and by viewing coolant flow through radiatorHeater

Verify proper heater function

Look for coolant on the floor in passenger compartment, smell for coolant smell in passengercompartment

Prevent and predict future problemsInspect hoses for excessive mushiness, excessive hardness, brittleness or cracking. Inspect hosesfor internal gaps that might indicate electrolytic breakdown. Also inspect hoses for evidence of

leaks.


Coolants 101

By Steve Litt

One could write a PHD thesis on coolants. This article simply strives to give a layman's overview of the subject.

Automotive coolant is a mixture of two liquids:





Water (ideally distilled)

Antifreeze

The antifreeze consists of two types of components:

Freeze inhibitorsCorrosion inhibitors

Current antifreeze products inhibit freezing with either ethylene glycol or propylene glycol. The former is a better

freeze inhibitor, boils at a higher temperature, and in a 50/50 to 70/30 mixture with water is a better absorber ofheat. The advantage of propylene glycol is it doesn't smell or taste as sweet, so animals and small children aren'tas tempted to drink it. This is important, because both ethylene glycol or propylene glycol are lethally poisonousin small quantities. The other advantage of propylene glycol is that in a pure form it absorbs enough heat to beuseful as a coolant, whereas pure ethylene glycol is not useful as a coolant in its pure form.

Propylene glycol/water mixtures have the disadvantage of not being measurable with a traditional specific gravitymeasurement tool. Instead these mixtures must be measured by the much more expensive refractometers. And,as previously mentioned, at all but the most concentrated mixtures, ethylene glycol solutions are more efficientcoolants.

"Ordinary" antifreezes use ethylene glycol as their freeze inhibitor. "Environmental" antifreezes use propylene

glycol. Most of the new "long life" antifreezes use ethylene glycol. They derive their long life from their corrosioninhibitors, not from a special freeze inhibitor.

Corrosion Inhibitors

As freeze inhibitors react with air and other chemicals over time, they become acidic. This causes corrosion to

the metal parts of the cooling system, and in fact can turn the whole system into a battery whose anodes(typically the aluminum parts) are consumed. Within a very short number of years, the radiator, water pump, andeven the hoses are corroded and clogged. Once that happens, the overheating begins, leading to a broken headgasket or worse if the compromised parts are not replaced. Corrosion protection is THE biggest factor inkeeping a cooling system healthy. Which is why antifreeze comes with corrosion inhibitors.

Ordinary "2 year" antifreezes use borates, phosphates and/or silicates as corrosion inhibitors. Most NorthAmerican standard antifreezes contain phosphates, which are great at corrosion protection, but can react withcalcium in tap water to produce radiator-clogging sentiment and scale. The harder the water, the more of aproblem this becomes. If you change your own coolant, you can avoid this by using only distilled water. At lessthan a dollar a gallon, it's a bargain.

Never use softened water in a cooling system. Softened water contains salt (NaCl), which becomes conductivein water and turns your entire cooling system into a battery, destroying first your aluminum parts, and then goingto work on even the cast iron.

The new "extended life" antifreezes are the same as conventional antifreezes except for their corrosion inhibitors.Most "extended life" antifreezes use organic acids instead of inorganic salts (borates, phosphates and silicates)

for corrosion protection. When used correctly, these organic acids are said to protect against corrosion for up to



5 years and 150,000 miles. There have been a few reports of problems with corrosion on lead-solderedcopper/brass radiators protected with organic acids, and also a few reports of sludging with organic acids. Theseare discussed in more detail in some of automotive author Larry Carley's writings (URL in this magazine's URL's

section). The two organic acid technology antifreezes approved by GM are Texaco/Havoline Dex-Cool andPrestone Long Life 5/100.

From the car company's point of view, organic acid corrosion inhibitors are great way to protect againstwarranty problems caused by customer neglect. Most warranties are over by 5 years or 150,000 miles. Once

your car is out of warranty and you are responsible for its upkeep, even if your car came with extended lifeantifreeze there's no reason you can't change the antifreeze more often. That way, if conditions are less thanperfect, you're improving your cooling system's chances. Texaco/Havoline Dex-Cool was selling for $6.99 agallon at my local Discount Auto Parts store -- the same price as conventional Prestone antifreeze.

Coolant Replacement Recommendations

In my opinion, unless you have a very good reason to do otherwise, you should use the manufacturerrecommended antifreeze for your car. The manufacturer has chemists and engineers on staff to figure out theexact best formula to use with the components in your car model. It's absurd to think that either you or anautomotive technician could second guess them in ordinary circumstances.

So what would constitute a very good reason? One would be a radiator replacement with a substantially differentradiator type. For instance, if the original was plastic and you put in an aluminum radiator, you'd need to totallyreevaluate your choice of coolant, as this is something the car company's engineers did not design. Likewise, ifthe original was lead soldered copper and you're replacing with plastic. The list goes on.

Another good reason would be a known design defect involving a specific antifreeze. Certainly if the

manufacturer later changed their antifreeze recommendation for a specific model, you should follow the newrecommendation. And in certain circumstances where experts believe that the manufacturer was wrong, and yourcar is now out of warranty, you may decide to take the risk of going against the manufacturer'srecommendations.

Never mix antifreezes. At best this would eliminate the long life of long life antifreezes, at worst it could cause a

new corrosion problem worse than either of the antifreezes by itself. When you switch antifreeze types, you musttotally drain the old antifreeze.


Do It Yourself Coolant Changes

By Steve Litt

If you're old enough to remember coolant changes before the age of environmental law, all I can tell you is"everything's changed". Letting the engine run for 30 minutes, with the radiator petcock open and a garden hose





pumping water into the radiator fill pipe is now seriously illegal. In most locales, all drained coolant must now becollected and taken to a licensed disposal facility. If the drained coolant is diluted with a garden hose, you might

have 100 gallons to bring in :-).

The environmental laws change everything. What was an easy 20 minute procedure is now a day-long affair,

complete with risks of injury, car damage, and legal difficulties. For that reason I've split this article in twosections:

Traditional do it yourself backflush/replacement changesEasier coolant maintenance methods

I recommend the easier coolant maintenance methods. The reason the traditional methods are discussed first is

so you understand all the hassle that goes along with the traditional methods. After reading the time, expense,difficulty and legal risks of traditional changes, I think you'll be ready to accept some of the disadvantages of theeasier coolant maintenance procedures. And once again, nobody said the traditional change methods are difficultin and of themselves -- they're just incredibly difficult to do legally.

Traditional do it yourself backflush/replacement changes

Probably the toughest part of changing your coolant is disposing the old coolant in a safe and legal manner.Ethylene glycol is a potent poison that smells and tastes sweet, so if left in a pan or on the ground animals andsmall children will drink it and die. Propylene glycol isn't as sweet so it isn't as tempting, but it's still a poison.

Before starting your coolant change, make sure you read this whole article and note the extreme hassles, damagerisks, legal risks, and personal injury risks in draining a cooling system in an environmentally responsible way.

Check with your city or county as to the lawful coolant disposal procedures. Sometimes those procedures arecostly enough that you're better off having a shop do your coolant change.

1. Pre-Drain procedures2. Drain the reservoir3. Drain the cooling system

4. Install the flush kit5. Flush6. 2nd Drain7. Add Coolant

8. Close system9. Test

Pre-Drain procedures

There exist various cooling system cleaners and flushers. The idea is that you add this liquid for 10 minutes andidle with the heater on full blast, or with some cleaners run the car for 6 hours and then drain and flush. I cannotcomment on possible harmful side effects of these cleaners and flushers. I wouldn't use them on a car that hashad annual coolant changes. They might be indicated on a car whose coolant is rusty, or a car whose radiator ispartially clogged. If you use these cleaners or flushers, try to research any possible side effects.



Drain the reservoir

There are various ways to do this, including removing and inverting the reservoir (pour it into a container fordisposal), or finding a way to drain it via the hose to the radiator fill neck. Another way would be to drain some

coolant, run the car until it's well warmed up (but never overheated), and shutting down the car. The coolant inthe reservoir should be sucked back into the radiator. You can also syphon the reservoir contents into a disposalcontainer, but NEVER syphon by mouth, because antifreeze is a potent poison that can be fatal.

After draining the reservoir, clean it by running a garden hose into it to remove dirt.

Drain the cooling system

Always make sure old coolant is poured into a pan -- never let it run into the ground or down the driveway andinto the storm sewers. Antifreeze is a sweet tasting poison, and it kills animals and even small children. Never letthe pan you drained it into remain unobserved, or a neighborhood dog or cat might die. Pour the contents of the

pan into closed containers, and if your county provides a liquid waste drop off center, bring the containers there.Always conform to your city or county's laws concerning antifreeze disposal.

It seems like everyone has their own technique for draining the cooling system. Here are a few:

Successive half-dilutionSingle half-dilution

Running quick emptyRunning quick empty with thermostat removedSimultaneous draining of radiator and engine

Successive half-dilution

The most common seems to be the successive half-dilution technique. This technique involves waiting for theradiator to cool, removing the radiator cap, draining the radiator through the radiator petcock, filling the radiator

with pure water, running the engine til hot with the heater on full blast. Every time this procedure is done theamount of antifreeze in the system is cut roughly in half, because at any one time about half the coolant resides inthe radiator and the other half in the engine and heater. Four such half dilutions will have diluted the antifreeze bya factor of 16, at which time it's less dangerous. But there's still a significant amount of antifreeze, so you might beviolating the law by flushing and letting the dilute spill. Not only that, but this method drains 2 to 3 gallons per

dilution, meaning you'll need to take 8 to 12 gallons to the licensed disposal facility. That's lots of containers, andlots of stuff to carry.

Be sure to let the engine cool completely each time, or you'll be burned severely when you open the radiator capand the radiator petcock.

Successive Half Dilution

PRO CON

Safe for the engineOnly the radiator petcock is touched

Takes a long time (cooling every dilution)Excessive materials to dispose of



Spills significant amounts of antifreeze during later flushRisk of injury if done wrong

Single half-dilution

Some recommend simply draining the radiator once, refilling it with water, and then starting the flush procedure.Thus only the radiator's contents are brought to the licensed disposal facility. The antifreeze remaining in theengine is diluted during flush and spilled onto the driveway and down the street gutters to the storm drain.

Although the flushing process greatly dilutes this antifreeze, it can still pose a grave danger for animals, it's notenvironmentally sound, and it's probably illegal in most locations.

Single Half Dilution

PRO CON

Safe for the engineOnly the radiator petcock istouchedVery quickVery little material to dispose of

Illegal in most placesSpills dangerous amounts of antifreeze during later flushSpilled antifreeze runs down the street and into the stormdrain

Any animal can drink it all along the way

Risk of injury if done wrong

Running quick empty

I used to do this. It's risky. Basically, with the engine cold, open the radiator petcock into a large collection pan,start the engine, and turn on the heater full blast. The radiator drains while the system is still cool, and when thethermostat opens, the engine and heater are likewise drained into the radiator. If the radiator petcock can drain

the coolant before the engine overheats, you're fine. Otherwise, you can cause an overheat and consequentialdamage.

As a practical matter, you'd want to watch the thermostat and shut down the engine when the temperature beginsto head for the red. Better still, have one person watch the petcock and one watch the temperature gauge, and

shut down when the draining stops, or when the engine begins to head for the red -- whichever comes first. If thedrainage was not complete, you'll need to use the dilution techniques discussed previously.

To increase your chances of a total drain, you might want to disconnect the lower radiator hose. This allowscoolant to drain very quickly, hopefully long before engine temperature becomes a problem. When removing thelower hose, try not to pry it off with a screwdriver, as that could damage the fitting on the radiator. If it won't

twist off or pull off, perhaps you shouldn't remove this hose, unless you want to carefully cut it off with a knife,and then purchase a new lower hose.

Running quick empty

PRO CON



Very quickAll coolant drained and gathered without dilutionLegal and environmentally sound

Risk of overheat and engine damageRisk of injury if done wrong

Running quick empty with thermostat removed

This is exactly like the normal running quick empty, except the lack of a thermostat means engine and heatercoolant will circulate to the radiator while the engine is still cold, thereby reducing the risk of engine damage.

One problem is that some coolant will spill when the thermostat is removed. Unless that spilled coolant is caughtin a pan, it's an environmental problem, a risk to pets and small children, and may be illegal.

One possibility is to start with a normal running quick empty, let the engine get cold, then remove the thermostatand do the second quick empty. The second quick empty occurs immediately instead of waiting for the engine towarm up. This lessens the risk of consequential damage to the water pump when it operates without liquid, andlessens the likelihood of overheat. To reduce it more, you might consider simply draining the radiator, closing thepetcock, and running until hot (at which time much of the engine's coolant will have moved to the radiator.

Because the thermostat is amongst the highest points of the cooling system, there's a good chance that it can beremoved without significant spillage.

Running quick empty with thermostat removed

PRO CON

Very quickAll coolant drained and gathered without dilutionLegal and environmentally soundGreat reduction in likelihood of overheat

Removing thermostat is time consumingSlight risk of overheat and engine damageIncreased possibility of coolant spillRisk of injury if done wrong

Simultaneous draining of radiator and engine

Most engines have one or more coolant drain plug to drain the engine itself. Theoretically, by opening all airbleeds, all engine drain plugs (remember to drain each into a pan), and the radiator cap and petcock (once again,drain into a pan), you can drain most of the system's coolant while the engine is cold and not running. Thiseliminates the risk of overheat and reduces the risk of personal injury. And assuming that you catch and turn in all

the drained coolant, it's one of the most environmentally responsible methods.

But drain plug locations are specific to specific car makes and models, and they're usually very difficult to get to.If you strip, shear or break an engine drain plug, you're in a heap of trouble, son. And you should really replacethe washers on those drain plugs -- and those parts might not be so easy to get. Before attempting this, be sureto obtain the manufacturer's documentation on coolant draining

Simultaneous draining of radiator and engine

PRO CON



All coolant drained and gathered without dilutionLegal and environmentally sound if care is takento avoid spillage when removing thermostatWhen done right, remores all risk of overheat

Reduces risk of burns

Loosening and replacing engine drain plugs isdifficult and time consumingDrain plug washers should be replacedDanger of damaging a drain plug, cross

threading it, or not being able to get it back in.Greater risk of injury due to working under thevehicleVery difficult and time consuming

Install the flush kit

You can buy a flush kit to "wash out" your cooling system. As far as I know, the law says you must have already

drained all your coolant, so that the only thing you're spilling is water. Check with your local authorities.

One way to flush the cooling system is to run it with the heater running full blast, the radiator petcock open andspilling on the ground (there's no more antifreeze left, remember), and a garden hose pouring in the radiator.Such a method would take a long time to do a good flush. A much more efficient flush method is to buy a flushkit. My local Discount Auto Parts store sells a Zerex flush kit for about $4.00.

The flush kit comes with the following parts:

Back flow prevention couplerFlushing TCap for flushing TTwo hose clamps

Deflector

According to the instructions, you start by installing the flushing T. Start with a cold engine. Cut the heater inlethose in a convienient place at least a couple inches from hot engine parts. It's the hose between the firewall andthe engine block, not the one between the firewall and the water pump. Remember, the system has been mostly

drained, so very little coolant will spill. Slip a hose clamp over the hose on each side of the cut, then slip thehoses over each end of the flushing T. The kit comes with three different sized flushing T's to accommodate anysized heater hose. Make sure the vertical part of the T is pointed upward. Then tighten the hose clamps so thatthe flushing T is permanently and securely installed. Finally, screw the appropriate end of the back flowprevention coupler onto the T. The instructions will tell you which end is appropriate.

Flush

One flushing method is running a garden hose into the radiator fill pipe of a running car with the radiator petcock

open. This method isn't particularly efficient.

The other way is to use a flush kit. The preceding section discussed its installation. To flush using a flush kit, dothe following on a car with a cold engine:

1. Screw a garden hose onto the back flow prevention coupler whose other end is connected to the flushing



T2. Make sure the radiator petcock is closed3. Remove the radiator cap4. Insert the deflector into the radiator fill pipe **5. Turn the heater control onto the high position

6. Turn on the water to the garden hose7. Start the car

** The deflector is made of a tough plastic. It snaps into the fill pipe with a tight pressure

fit. I believe that with an old corroded metal radiator, or a radiator with a plastic fill pipe,it's conceivable that such a press fit could damage the fill pipe. The only function of thedeflector is to move the spillage away from the car. You might decide it's better to let thewater spill right out of the fill pipe.

Also, the deflector is too short to move the spilled water away from the car. If you use the deflector, you mightwant to tape a short length of hose to it in order to move the spillage entirely away from the engine compartmentand car. Do not let the hose get anywhere near the fan, fanbelts, or other moving parts, or the result could besevere damage or injury.

WARNING!

If you connect the back flow connector in the wrongdirection, or if the back flow connector malfunctions, or if

you forget to remove the radiator cap, it is possible for thecar's coolant to "back up" into the hose and into the watersupply. This is an extreme sanitary breach, and if there aresignificant toxins in the cooling system (flushing solutionsand antifreeze are both very toxic), people could be

poisoned. Be VERY careful!

Run the car until the fluid coming out the radiator has been clear for five minutes. At that point your coolingsystem can be considered flushed and clean.

2nd Drain

Shut down the engine and wait for it to cool. It shouldn't be very hot because you've been moving cold waterthrough and out of it. If you're using a flush kit, remove the back flow prevention coupler from the flushing T.

Turn the heater on full hot. Remove the radiator cap and open the radiator petcock. let drain. Because you haveall clean water in the system, there's no need to drain the engine.

Add Coolant

Close the petcock. If you're using the flush kit, leave the flush T open. Turn the heater to the full heat position.Open any bleeder valves that are reasonably easy to open.



Look up in your owners manual the amount of antifreeze (not coolant, but the amount of antifreeze necessary tofill the cooling system with 50/50 coolant (or whatever mixture you need to give freeze protection for your

coldest days). If your owners manual lists only the cooling system's fluid capacity, divide that amount by 2 for theamount of antifreeze to make a 50/50 mixture. If, in order to protect against freezing in extremely cold weather,you need a 60/40 mixture (60% antifreeze), multiply the cooling system fluid capacity by 0.6.

Put that amount of pure antifreeze in your radiator. Then top off with distilled water. Make sure you add enough

to bleed all air from the system. You should see some coolant come out the bleeder valves and/or flush T.

The reason you don't simply add 50/50 is that the engine contains 100% water, so you could never reach 50/50by adding 50/50. Similar logic applies for any mixture percentage.

Close system

Close the bleeder valves. Put the cap on the flushing T. Install the radiator cap

Test

The big reason for testing is that air can get trapped in the system. Trapped air can cause overheats in two ways:

1. By creating a low coolant situation2. By creating a bubble around the thermostat's heat sensor, so that the thermostat "thinks" the engine is cool

and does not open

Most of the trapped air comes out within minutes after running the car. Some comes out for a few days after. Asthe air comes out, it must be replaced by the desired mixture of coolant.

Run the car for several minutes, revving the motor every once in a while. Shut down instantly if the temperaturestarts heading for redline. Otherwise, let it run for 15 minutes and then shut down. Open the hood, and fill thereservoir to the "full, hot" mark with the proper mixture of coolant. Let the engine cool. Then open the radiator

cap, and if the coolant isn't up to the top, top it off with the proper coolant mixture. Repeat until the cool enginedoesn't require a top off.

Then, for the next few mornings, remove the radiator cap and verify that the coolant is up to the top, and if itisn't, top it off with the proper coolant mixture. Likewise, if the reservoir coolant level is below the "full, cold"level, top off the reservoir with the proper mixture.

Easier Coolant Maintenance Methods

Do the traditional methods seem to involve too much time, hassle, injury risk, and legal risk? How did you likethe risk of accidentally backing up your coolant into the water supply if you accidentally build up pressure in thesystem and the back flow prevention coupler fails or is connected wrong? Might that involve some fines andlawsuits?

There are two easy methods for coolant maintenance. One's not as thorough as the traditional methods, and oneis expensive and might not be as thorough. But they both lower the risks of damage, injury, environmental harm



and legal liability to acceptable levels. When viewing the deficiencies of these methods, keep in mind that the

traditional alternatives might be even less attractive. The two easy methods are:

Frequent radiator drains

Letting a professional do it


One interesting solution to the flushing problem is to replace quality with quantity when it comes to coolantreplacement. Instead of replacing every drop of coolent every year or two, replace half the coolant every 6months. This can be done by draining and refilling the radiator, without the hassle of draining the engine. Whendone this way, you can consider the 6 months between the radiator drain/replacements as a long "flush" period.This solution is quick and cheap.

Start with the engine cold, and open radiator cap and then the radiator petcock and drain the radiator into a panfor disposal at the disposal facility. Also, find a way to drain the reservoir into that same disposal pan. Add agallon of water to the radiator with a garden hose, and catch what comes out the petcock in the pan That shouldremove most of the remaining ounces of coolant.

Unless you're extremely environmentally responsible, you can then rinse the radiator and reservoir with a garden

hose. After all, probably there are only a few drops of coolant left in the radiator, and you're diluting that coolant100 to 1, so risk to animals and the environment is minimal. Once again, allow the radiator to drain completely,and then close the petcock. Now fill the radiator with the proper antifreeze/water combination for your climate,squeezing the hoses to try to free air bubbles.

If all went well you didn't introduce air pockets into your cooling system. But sometimes air pockets happen.

Too much air can cause overheats, either through a low coolant condition, or by an air bubble surrounding thethermostat's temperature sensor.

Fill the reservoir to the "full, cool" line with the proper mixture for your climate. Place a closed bottle of thatmixture in your trunk for use while testing. Now start the engine and drive it around the block a few times,

keeping a VERY careful eye on the temperature gauge. If it starts to move toward the redline, shut it downimmediately. Otherwise, after about 10 minutes pull back into your driveway. Either way, with the engine hot,top off the reservoir to the "fill hot" line with the proper mixture. When the car is cold again, note the reservoirlevel. If it's below the "full, cool" level, repeat the instructions in this paragraph.

Every day for a week, when you get up in the morning, before starting the car open the cold radiator and top off

with the proper coolant mixture if necessary, and top off the reservoir to the "full, cool" line. This is replacementof air that got burped out during yesterday's driving. During the first week watch the temperature gauge verycarefully. If you have no gauge (only an idiot lite), try not to go on long drives for the first week, and check thereservoir level every time you come out to the car.

For even better accuracy, before refilling with coolant, measure the coolant mixture with a hydrometer (assuming

you've always used ethylene glycol), and when calculating the replacement mixture, make sure to compensate forany excess in the existing mixture.

This method takes maybe 15 minutes (not counting around the block testing or the trip to the licensed disposal



facility), it's performed almost entirely on a cold engine, it's cheap (typically a gallon or 1.5 gallons of antifreeze),it's environmentally sound because it's trivially easy to catch all the coolant.

Each time you perform this procedure you replace roughly half the coolant, and as a simplification you canassume you're removing 1/2 of the coolant's disolved impurities. If you do this procedure twice a year (that's

about $20.00 and a half hour of your time plus time spent testing and at the disposal facility), you've replaced75% of your coolant every year, and every 2 years you've replaced 93.75% of your coolant. This isn't as gooddoing a 100% replacement and backflush every 2 years, but if you continually refill the radiator every 6 monthsit's probably good enough to keep your cooling system healthy for a very long time. And remember, withoutknowing exactly what an auto shop does, it's very possible that this procedure is actually more thorough than

what the shop does.

A huge advantage of frequent radiator drains is that you control the water being used. By using only distilledwater, you cut way down on the likelihood of calcium-caused deposits. Even if your system started with tapwater, within 4 changes you've replaced 93.75% of the old tap water with distilled water.


PRO CON

Legal and environmentally sound if you'rereasonably careful not to spill.

Extremely fast and easyWhen done right, removes all risk of overheatReduces risk of burnsYou know exactly what went into the systemYou can use distilled water

Not as thorough as a flushMay not reduce heavy deposits in a previously

undermaintained carMust be done every 6 months


Perhaps the easiest solution is to let a professional clean, flush and replace the coolant. You need to ascertainthat the professional will really remove all (well, 99%) of the old coolant, flush the system with water, drain theflushed water, and then replace with brand new coolant. Some professionals merely drain the and rinse theradiator, and then refill with the correct solution. You could easily do that yourself -- it's not what you're payingthem to do.

Be sure the professional uses the correct antifreeze for the car. Some shops don't take the time to look uprecommendations. And ask whether the shop is using recycled antifreeze. Recycled antifreeze is made from oldantifreeze and contaminants -- many from cars much dirtier than yours. The quality of recycled antifreeze isdependent on the ability of the recycling machine to filter out whatever bizarre contaminants were present in the

raw material, and upon the corrosion inhibitor which the shop adds. With new antifreeze priced at $6.99 a gallon(add a couple bucks for the shop's markup), recycled antifreeze might not be worth it.


PRO CON



Effortless and not timeconsumingYou are not responsible

for coolant disposal orany environmental orliability problems.

Costs moneyRequires being without your car for hours or daysYou need to research how the professional does the job. For instance,

some professionals simply drain the radiator and pour in coolant. Youcould have done that yourself in less time than it takes to drive to theshop.


Life After Windows: Nothing New to Report

Life After Windows is a regular Troubleshooting Professional column, by Steve Litt, bringing you observations and tips

subsequent to Troubleshooters.Com's Windows to Linux conversion.

By Steve Litt

Have you heard the phrase "no news is good news"? Have you heard the ancient Chinese curse, "may you live ininteresting times"? Sometimes boring is good.

My computing life is uneventful these days. I write books, just like I always have, except now I have superior

book writing software (LyX). I use outlines just like I always have, except now my outline processor(VimOutliner) is keystroke friendly and extremely fast. I write web pages just like I always have, using the Linuxversion of the software I've always used (Netscape Composer). I do weekly and monthly backups just likealways, but now I can script the whole thing (tar and cdrecord) instead of enduring the irritation of point andclick.

Life after Windows? It's business as usual.

Steve Litt is the author of the course on the Universal Troubleshooting Process. He can be reached at Steve Litt's emailaddress.

Linux Log: You Just Might Like Linux

By Steve Litt

Do you long for simple and inexpensive cars like the Chevy Bel Air, the Dodge Dart or the original Volkswagen

Beetle? Then you just might like Linux. You can put together a Linux system with no Graphical User Interface(GUI) to clutter up memory or callstack. Such a system can do more with a low power Pentium computer thanmodern systems with Windows.



http://www.troubleshooters.com/utp/tcourses.htm




Do you long for the maintainability of the Bel Air, the Dart, or the original Beetle? Then you just might like Linux.Like the cars of yesteryear that could be repaired with little more than an adjustable wrench, the Linux computer

can be repaired with a text editor and a few basic built-in diagnostic tools. No regedit or DLL evaluationnecessary.

But maybe you're more the Lincoln Town Car type of guy. Then you just might like Linux. I'm writing thismagazine on a dual Celeron 450 with 512 Meg of RAM and 80 Gig of 7200 RPM disk, using Mandrake Linux.

I have LyX book authoring software, which is definitely the Cadillac of the industry. For daily drives through webauthoring land I use Netscape Composer. I have email clients, news clients, irc clients, and everything else I'dever need for a full featured desktop computer.

Which is boring to an eight barrel carburetor Pontiac Trans Am type of guy. If you like to soup up your TransAm, you just might like Linux. With Linux, you can download and install almost any conceivable type of

software. And if you can't download it, you can code it yourself. And when it comes to performance, Linux isking. As installed. But if you want some extra performance, you can tweak Linux for plenty of extra horsepower.

If you're an environmentalist who has an electric or hybrid car, you just might like Linux. Linux doesn't use orsupport the Microsoft Monopoly. The Microsoft Monopoly limits everyone's choice and depletes the e-zonelayer.

Perhaps you're the price sensitive type, driving a Kia Rio or Toyota Echo. You just might like Linux. A fullfeatured Linux box set with bundled customer service costs between $29.00 and $89.00. A CheapBytes.ComCD set can cost less than $15.00, delivered. Or, if you have broadband connectivity, you can download yourfavorite Linux distribution free of charge. Better yet, when you use Linux, most of your software is free. The LyXprofessional book authoring software is free. The Gimp professional graphic editor is free. The OpenOffice office

suite is free. The server software most common to the Internet is free. And don't forget that because Linux ismore efficient, you spend less on hardware for a given performance level.

Price is important, but you might be the type who searches Consumer Reports for the most reliable car. If so,you just might like Linux. Linux seldom freezes, and when it does you can usually unfreeze it by finding and killingthe rogue process with the top command. Unlike some of its competitors, installing applications usually does not

affect the underlying operating systems, and "de-installing" a Linux application usually removes all trace. WhileLinux's competitors place their graphical user interface in the kernel, meaning a graphics crash can bring downthe whole system, Linux places the graphics outside the kernel, where it can easily be stopped and startedindependent of the operating system.

Are you the type who pays cash for your car so you own it instead of the bank or the leasing outfit? Then youjust might like Linux. With Linux, you own your software and data. You can legally modify your software anyway you like. Because most Linux data is text, you can use editors and scripting languages to access and modifyyour data. You can switch to another distribution or operating system any time you want. Unbelieveably, it isperfectly legal with most Linux distributions to install your Linux distribution on multiple computers, whether or

not those computers belong to you. Contrast this with modern commercial operating systems, which prohibitreverse engineering, force you to register your operating system, and cease working if your hardware changessubstantially. Rumors abound that many commercial software vendors are considering moving to a softwarerental scheme. If ownership of your operating system, your computer, and your data itself is important to you,Linux is your operating system.



Are you one of the few skilled enough to build your own car from a kit? Then you just might like Linux. TheLinux From Scratch (URL in URL's section) website gives complete instructions on how to build a Linux systemwith source code you download and compile yourself. It's a lot of work, but once you've completed this project,

you have exactly the system you want, with no extraneous features or geegaws. And you intimately know everysoftware component in your system.

Linux comes in several models (distributions in Linux-speak). Distributions include market leader Red Hat, easydesktopping Mandrake, Ultra-free and maintainable Debian, trivially simple Lycoris, and no-frills Slackware.URL's for these distributions are in the URLs section of this magazine. Additionally, there are tens of other

widely used distributions. Each distribution focuses on a specific needs scenario, but like the Chevy Bel Airs ofthe 60's, Linux is so easy to work on that you can add any functionality to any distribution.

But Linux isn't for everybody. If you're the type who drives to the closest dealership, relies on the salesman for aquick features per dollar comparison, and buys a car, you probably won't like Linux. Linux requires a little more

planning.

If you suspect your current computing experience isn't the best it can be, do yourself a favor and investigateLinux. You just might like it.

Steve Litt is president of Linux Enthusiasts and Professionals of Central Florida (LEAP-CF). He can be reached at SteveLitt's email address.

Letters to the Editor

All letters become the property of the publisher (Steve Litt), and may be edited for clarity or brevity. We especially welcomeadditions, clarifications, corrections or flames from vendors whose products have been reviewed in this magazine. We reserve theright to not publish letters we deem in bad taste (bad language, obscenity, hate , lewd, violence, etc.).

Submit letters to the editor to Steve Litt's email address, and be sure the subject reads "Letter to the Editor". We regret that wecannot return your letter, so please make a copy of it for future reference.

How to Submit an Article

We anticipate two to five articles per issue, with issues coming out monthly. We look for articles that pertain tothe Troubleshooting Process, or articles on tools, equipment or systems with a Troubleshooting slant. This can be

done as an essay, with humor, with a case study, or some other literary device. A Troubleshooting poem wouldbe nice. Submissions may mention a specific product, but must be useful without the purchase of that product.Content must greatly overpower advertising. Submissions should be between 250 and 2000 words long.

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prohibit substantive modifications. However, in order to publish your article in Troubleshooting ProfessionalMagazine, you must decline the option to prohibit commercial use, because Troubleshooting ProfessionalMagazine is a commercial publication.

Obviously, you must be the copyright holder and must be legally able to so license the article. We do not

http://www.leap-cf.org/




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Troubleshooters.Com reserves the right to edit any submission for clarity or brevity, within the scope of theOpen Publication License. If you elect to prohibit substantive modifications, we may elect to place editors notesoutside of your material, or reject the submission, or send it back for modification. Any published article will

include a two sentence description of the author, a hypertext link to his or her email, and a phone number ifdesired. Upon request, we will include a hypertext link, at the end of the magazine issue, to the author's website,providing that website meets the Troubleshooters.Com criteria for links and that the author's website first links toTroubleshooters.Com. Authors: please understand we can't place hyperlinks inside articles. If we did, only thefirst article would be read, and we can't place every article first.

Submissions should be emailed to Steve Litt's email address, with subject line Article Submission. The firstparagraph of your message should read as follows (unless other arrangements are previously made in writing):

Copyright (c) 2001 by <your name>. This material may be distributed only subject to the terms and conditions set forth in theOpen Publication License, version Draft v1.0, 8 June 1999 (Available at http://www.troubleshooters.com/openpub04.txt/(wordwrapped for readability at http://www.troubleshooters.com/openpub04_wrapped.txt). The latest version is presentlyavailable at http://www.opencontent.org/openpub/).

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After that paragraph, write the title, text of the article, and a two sentence description of the author.

Why not Draft v1.0, 8 June 1999 OR LATER

The Open Publication License recommends using the word "or later" to describe the version of the license. Thatis unacceptable for Troubleshooting Professional Magazine because we do not know the provisions of that

newer version, so it makes no sense to commit to it. We all hope later versions will be better, but there's alwaysa chance that leadership will change. We cannot take the chance that the disclaimer of warranty will be droppedin a later version.

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All trademarks are the property of their respective owners. Troubleshooters.Com(R) is a registered trademark of

Steve Litt.

URLs Mentioned in this Issue

MISC URLshttp://www.troubleshooters.com: The website administered by TPM author Steve Litt.http://www.troubleshooters.com/bookstore/: Home of Steve Litt's books, "Rapid Learning: Secret

Weapon of the Successful Technologist" and "Troubleshooting Techniques of the Successful

http://www.troubleshooters.com/tlnktrad.htm

http://www.troubleshooters.com/

http://www.troubleshooters.com/bookstore/





Technologist".

AUTOMOTIVE WEBSITESLarry Carley's writings

http://members.aol.com/carleyware/library/coolant.htm: An excellent discussion of coolants.http://www.babcox.com/editorial/cm/cm59730.htm: A basic discussion of antifreeze.

http://www.babcox.com/editorial/tr/tr110046.htm: An in depth discussion of coolanttechnology.

http://www.learn2.com/07/0714/071412.asp <great tutorial>This excellent in-depth tutorial walksyou through all steps of what I call the "frequent radiator drain". http://www.delanet.com/~pparish/cool-dg.htm: This is an excellent predefined diagnostic script,

divided into static inspection (engine off) and dynamic inspection (engine on).http://www.cardogz.com/columns/auto/archive/1998_06_15.html: Several scary scenarios thatshould get the attention of even the most unobservant car driver. Note that I personally have troublebelieving one assertion he makes -- that "By leaving the thermostat out, [...] in certain cases thecoolant will not stay in the radiator long enough to be cooled."

http://www.consumeraffairs.com/automotive/toyota_errors.html: This site pins the difficulty ofradiator flushing on environmental laws.http://autorepair.about.com: A wonderfully complete automotive resource, with lots of links and

some local content too. Very nice cooling system links! My one suggestion for improvement of thissite is to include a link to the Troubleshooters.Com Overheating pages.http://www.autosite.com/garage/encyclop/tocdoc.asp: Fantastic information on all systems of anautomobile. The cooling section has some hard to find information.http://www.troubleshooters.com/tautomot.htm: A wonderful page of automotive troubleshooting

links.

LINUX DISTRIBUTIONS

http://www.us.linuxfromscratch.org: Build your own Linux instead of accepting a vendor's distro.Their tag line says it all: "Your distro. Your rules."http://www.redhat.com: Home of the Red Hat Linux distribution, which is the most widely used.http://www.mandrake.com: Home of the Mandrake Linux distribution, which many feel is the bestall around Linux distro for the desktop. I do all my work on Mandrake Linux (8.0 right now).

http://www.debian.org: Home of the Debian GNU/Linux distribution. Debian has two claims tofame: 1) It's entirely free software, and 2) their upgrade techniques are web based and said to bevery easy.http://www.slackware.org: Home of the Slackware Linux distribution. Slackware is one of theoldest distributions. Today its market focus is on the heavy duty technologist who neither wants nor

needs hand holding.http://www.lycoris.com: Home of the Lycoris Linux distribution. Formerly called "Redmond Linux",it's aimed at the stereotype non-technical person who would typically use Windows. Their tag linesays it all: "Linux is for everyone".


http://members.aol.com/carleyware/library/coolant.htm

http://www.babcox.com/editorial/cm/cm59730.htm

http://www.babcox.com/editorial/tr/tr110046.htm

http://www.learn2.com/07/0714/071412.asp

http://www.delanet.com/~pparish/cool-dg.htm

http://www.cardogz.com/columns/auto/archive/1998_06_15.html

http://www.consumeraffairs.com/automotive/toyota_errors.html

http://autorepair.about.com/

http://www.troubleshooters.com/tautomot.htm

http://www.us.linuxfromscratch.org/

http://www.redhat.com/

http://www.mandrake.com/

http://www.debian.org/

http://www.slackware.org/

http://www.lycoris.com/

Documents

April 2002 Troubleshooting Professional Magazine_ Automotive Cooling System Maintenance and Repair