protection of the cooling system for heavy duty diesel engines · receive maximum protection for your cooling system, ... molybdate, nitrate, nitrite, phosphate, silicate. ... Scale

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Cummins FiltrationBlock C, ground floor

Pellmeadow Office Park60 Civin Drive, Bedfordview

Tel: 011 454 5431www.cumminsfiltration.co.za

protection of the cooling system for heavy duty diesel engines1. introduction

Diesel engines continue to be the work horse engines of industry Advances in diesel engine technology are being driven by needs for increased power, emission reductions, improved fuel economy, and longer reliability.

Engine manufacturers always recommend using a fully formulated coolant. Fully formulated coolants contain the appropriate amounts of glycol, de-ionized water and coolant additives (also known as supplemental coolant additives or SCAs) mixed together as a complete coolant package. There are standard service interval coolants and extended service interval coolants. Water filters containing SCA can provide a convenient and reliable method for delivering supplemental additives and coolant extenders which replenish the additive chemistries used during the respective service interval.

Estimates project that more than 40% of heavy duty engine repair costs are related to the cooling system. It is critical that you receive maximum protection for your cooling system, with minimum maintenance hassle, to prevent downtime and lower your total operating costs.

The benefits of using coolant additives as a regular part of cooling system maintenance program include:

• Extended water pump life• Maximized cavitation corrosion protection• Extended coolant life• Improved heat transfer• Improved thermostat durability• Lower cooling system maintenance costs

2. types of engine coolant

The more severe operating conditions and environments in which heavy duty diesel engines operate have an impact on coolant formulations and performance.

Ethylene glycol-based engine coolants are still the predominantly used heat transfer fluid for heavy duty applications. Several different types of engine coolants are used in heavy duty applications, which may be classified by the type of corrosion inhibitors contained in the formulation. In the United States, conventional coolants with the addition of supplemental coolant additives SCAs, traditional “fully formulated” coolants, extended service interval coolants, and extended life coolants are all used in heavy duty applications. In Europe, Asia Pacific, and other parts of the world, conventional, hybrid, and extended life coolants are used in heavy duty applications. However, there is less distinction between light duty and heavy duty coolants and less usage of SCAs outside the United States.

A description of the various types of heavy duty HD coolants is provided in Table 1. Engine coolants used in heavy duty applications

must provide satisfactory performance in the areas of:

• oxidation-thermal stability;• high temperature corrosion protection;• cavitation corrosion protection;• erosion corrosion protection;• elastomer compatibility;• hard water stability; • anti-scaling properties, and preferably; • non-depleting coolant chemistry.

table 1. type of hd engine coolants.

Conventional coolant

Contains inorganic corrosion inhibitors such as borate, molybdate, nitrate, nitrite, phosphate, silicate. In Europe, phosphate is generally not used due to potential hard water compatibility problems. In Asia, silicates are generally not used due to gel and water pump seal abrasion concerns.

HD extended life coolant

An engine coolant containing Organic AcidTechnology (OAT) providing long service life. These products may contain nitrites or molybdate, or both, and may be re-fortified with an “extender” at typical service intervals of 480 000 km or longer.

HD extended service interval coolant

An engine coolant also providing extended service life. SCAs are typically added at 160 000 - 240 000 km intervals.

Hybrid coolant An engine coolant containing a combination ofinorganic and organic corrosion inhibitors. Europe hybrids are phosphate free. Asia hybrids are silicate free.

Organic AcidTechnology (OAT)

Any group of carboxylic acids including aliphatic mono and diacids and aromatic acids applicable as corrosion inhibitors in coolants.

Supplemental Coolant Additive (SCA)

A chemical additive that is periodically added to the coolant to maintain protection against general corrosion, cylinder liner pitting, and scaling in heavy duty engines.

Traditional fullyformulated coolant

A conventional coolant containing an initial dosage of SCA. These coolants require periodic addition of SCAs typically at 32 000 km intervals.

3. more on supplemental coolant additives

Supplemental coolant additives (SCAs) expand the protection abilities of the coolant in terms of both time and amount. Over time, however, the concentration of SCAs will gradually deplete during normal engine operation. Although SCAs provide protection for the cooling system components, it’s just as important that the coolant have them in proper concentration.

The proper application of SCAs will provide: • pH control to prevent corrosion• Water-softening to deter formation of mineral deposits• Cavitation protection to reduce the effects of cavitation

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Check the operator’s manual for the diesel engine you are working on, as the proper dosages for initial cooling system fill and proper maintenance are required.

The concentration of SCAs will gradually deplete during normal engine operation. Check the SCA concentration during normal engine operation and at regular intervals. Additional SCAs must be added to the coolant when it becomes depleted below the specified level.

Silicate Gelation. Sodium silicate is added to the antifreeze to protect the aluminium surfaces from corrosion and pitting. Silicate gelation is the tendency for silicate that is added to antifreeze to drop out of the solution and form a jelly like substance that will plug radiators, heaters, after-coolers and other parts of the cooling system.

This drop out of silicate can be attributed to a combination of factors and cooling system interactions, including: • Higher amounts of silicate and phosphate in coolant• Hotter running engines• After-coolers• Additive packages When antifreeze is over concentrated with SCAs, the excess silicate will drop out of the coolant and form silicate gel on heat transfer surfaces. This results in reduced coolant flow and engine overheating. It is also possible for silicate to drop out at low coolant temperature and plug radiator tubes. The reduction of the sodium silicate in the coolant makes the solution evaporate in a shorter period of time. Additionally, coolant that has evaporated due to the drop out of silicates will leave a white, caked, powder-like substance.

4. Key coolant performance areas

4.1 Oxidation-thermal Stability

Since engine coolants are hydrocarbon based, the ethylene glycol-based fluid is susceptible to oxidation which involves reaction of ethylene glycol with oxygen to form glycol degradation acids glycolic acid: HO-CH2-COOH, formic acid: HCOOH, oxalic acid: HOOCCOOH, etc..

Certain additives in coolants such as nitrites, which are used to protect cast iron/cylinder liners from corrosion, may also undergo oxidation to form nitrates. The increased thermal loading and more severe operating conditions higher temperatures, aeration, pressure, and any cooling system contaminants/corrosion metals occurring in today’s engines are factors that can accelerate oxidation and shorten coolant life.

4.2 Cavitation

4.2.1 Understanding cavitation

In elastic media such as air and in most solids, there is a continuous transition as a sound wave is transmitted. In non-elastic media such as water and in most liquids, there is continuous transition as long as the amplitude or “loudness” of the sound is relatively low. As amplitude is increased, however, the magnitude of the negative

pressure in the areas of rarefaction (pockets of low pressure) eventually becomes sufficient to cause the liquid to fracture, causing a phenomenon known as cavitation.

Cavitation bubbles are created at sites of low pressure as the liquid fractures or tears because of the negative pressure of the sound waves in the liquid. As the wave fronts pass, the cavitation bubbles oscillate under the influence of positive pressure, eventually growing to an unstable size. Finally, the violent collapse of the cavitation bubbles results in implosions, which cause shock waves to be radiated from the sites of the collapse. The collapse and implosion of myriad cavitation bubbles throughout an ultrasonically activated liquid result in the effect commonly associated with ultrasonics. It has been calculated that temperatures in excess of 5000OC and pressures in excess of 70,000 kpa are generated at the implosion sites of cavitation bubbles.

4.2.2 Effect on engine components

Air can enter the system through leaks or through a faulty radiator cap. This leakage reduces cooling system pressure and increases the potential for the formation of bubbles in the coolant. These bubbles will eventually cause an increase in pitting of the metal surface in the cooling system. Water pump impellers and the housing itself can be the victim of cavitation caused by low system pressure or by air trapped in the system. Radiators and heater cores can also be damaged by cavitation caused by the same condition(s).

4.2.3 Preventing cavitation

Since cavitation cannot be prevented entirely, the use of supplemental coolant additives (SCAs) is necessary to provide a continuous protective coating on the metal surfaces in the cooling system. This coating will aid in controlling and limiting the damage done to the engine as a result of cavitation.

The single most important procedure in controlling damage caused by cavitation is keeping the cooling system clean with periodic flushing. The use of clean water combined with flushing agents will scrub the system of impurities, scale or other buildup allowing for a “fresh start” with the introduction of the new anti-freeze/water mixture.

4.3 Anti-scaling performance

Scale resulting from the use of hard water, cooling system contaminants, and corrosion inhibiting film agents can block the ability to transfer heat resulting in overheating and metal fatigue failures. Previous studies reported that scale layers in the range of 0.254 to 0.127 cm on the metal surface can significantly retard heat transfer and increase metal surface temperatures 38 - 93°C around the head or upper part of the cylinder liner depending on conditions of heat flux and coolant flow .

figure 1. Wet-sleeve cavitation

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Scale tends to form in specific areas of the hot side of the engine resulting in localized hot spots, which also accelerate oxidation degradation of the coolant. The use of good quality water and properly inhibited coolants minimizes these deposits.

4.4 Erosion-Corrosion

Erosion-corrosion protection is becoming more important in view of the increased use of soft metals aluminium, copper, and lead in various engine and cooling system components and the more severe operating conditions of higher coolant flow rates. Erosion-corrosion is typically caused or accelerated by excessive flow conditions which generate shear forces sufficient to remove corrosion passivating films or naturally protective oxides, or both.

Erosion-corrosion is most prevalent with soft metals which have critical or limiting flow velocities. Other factors including turbulence, cavitation, impingement, galvanic effects, and abrasive contaminants casting sand, machining debris can add to the severity of the attack. Erosion-corrosion problems have been observed in the field with brass fuel injector cups, aluminium alloy oil coolers, and aluminium heater cores with several different types of coolants.

4.5 Elastomers, seals, and hoses

Elastomers, seals, and hoses are extremely important since they are widely used throughout the engine and cooling system. Common elastomer materials used in the engine and cooling system include nitrile rubber NBR, hydrogenated nitrile rubber HNBR, ethylene propylene terpolymer EPDM, tetrafluoroethylenepropylene copolymer FEPM, and silicone.

The more severe operating conditions higher coolant temperatures, higher under the bonnet temperatures, greater amount of hot regions in the engine may be having effects on both elastomer/hose and coolant life. In some cases where coolant passages are extremely narrow almost filter size such as oil cooler or water pump seal faces, or both, hose-coolant interaction products or other contaminants, or both, can plug the passages resulting in reduced heat transfer, severe oxidation of the coolant, or equipment failure, or a combination thereof.

5. coolant maintenance

Proper cooling system maintenance combined with the correct or recommended antifreeze and SCA will provide protection for the internals of a diesel engine for thousands upon thousands of highway miles. Six of the most common coolant related problems are given in table 2 on the next page.

The experts recommend inspecting it at the vehicle’s regular maintenance intervals to make sure it’s clear (no rust), that the colour is right (not mixed with another antifreeze type) and that it has sufficient freeze/boil protection, best determined by using a refractometer.

Maintenance guidelines for cooling systems with fully formulated conventional anti freeze typically include periodic testing of SCA levels and appropriate adjustment, as well as periodic draining, flushing and refilling the system to avoid, as already noted, an excess of dissolved solids.

You can test the additive concentration of fully formulated conventional coolant by supplying samples to a fluids-analysis laboratory. Or, you can do the testing yourself by using paper test strips, which are chemically sensitive and change colour to indicate freeze/boil point (glycol content), nitrite (or nitrite/molybdate) levels and, in some instances, pH.

When the addition of an SCA is indicated, keep in mind that two major types of SCA are available, one with a nitrite/borate formulation, the other with a nitrite/molybdate/phosphate formulation. It’s probably best not to mix them, and it’s best to use a test strip designed for the specific formulation.

Some users of fully formulated conventional antifreeze employ a coolant filter charged with an SCA package. This filter/additive assembly is designed to release metered amounts of additives over time and, thus, to maintain optimum levels. As long as testing indicates proper additive levels, and provided that top-up is done with a 50/50 mix of the correct antifreeze and de-ionized water, the assumption is that fully formulated conventional coolant can last far longer than the often-prescribed interval of two years.

On the other hand, some users of fully formulated conventional antifreeze drain and replace coolant every year, but do not test or add SCA packages between those service intervals, thinking that nothing will go wrong in that short time. But, depending on the specific formulation of the antifreeze and on top-up practices, critical additives could be depleted in as little as 1,000 hours, potentially leaving the engine virtually unprotected for a long time.

6. coolant filtration

Diesel engines have traditionally been fitted with bypass coolant filters. Some filters are engineered to be attached to the engine itself, others are added as remote devices in the system. The filters usually contain coolant additives, although some fleets found the use of “blank” coolant filters and liquid SCAs to be more cost-effective. Because engine coolant filters are not necessary as additive delivery devices in various new coolants, some users have omitted (new production) or removed (existing units) coolant filters from vehicles operating on ES coolants. This was done to reduce cost. However, earlier studies found that the value of coolant filtration extends beyond their convenience as additive delivery devices.

There are different types of coolant filters in the

figure 2. coolant test strips*

figure 3. additive containing coolant filter*

*Images courtesy of Cummins Filtration

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marketplace. Most contain coolant additive (SCA) or extender in a dry form that, once properly installed,delivers a measured weight of replenishing additive to the coolant within a few hours of normal operation. A properly formulated SCA will quickly dissolve in the coolant and provides a significant benefit to the cooling system, thereby extending the life of the coolant and reducing the overall cost of cooling system maintenance.

Another type of coolant filter contains no additives. In this case the user, in compliance with the recommendations of the coolant and/or engine manufacturer, must maintain the coolant chemistry manually. These filters would be the most appropriate types for some “extended service” coolant technologies. Finally, there exist sophisticated extended service filters. These filters deliver replenishing additives to conventionally and some hybrid coolants either through time-release or delayed release technology. In this way a robustly constructed filter may stay in service a year or more, providing extended coolant life benefits, protection in the event of minor coolant dilution or contamination, and waste reduction all while being very cost-effective.

Common reasons for choosing a water filter are:

a. adding water filter capability to an existing coolant system.

The addition of a water filter head and filter can provide significant benefits to the engine, including:

• Extended water pump life.• Maximized cavitation corrosion protection.• Extended coolant life.• Improved heat transfer.• Improved thermostat durability.• Lower cooling system maintenance costs.

The following coolant related problems are possible signs of debris/contaminant in the coolant coupled with poor to no filtration:

• Worn rings and scuffed pistons due to poor heat transfer.• Premature water pump failures.• Premature thermostat failures.• Premature radiator failures.

Field tests returns have noted that 40% of used water filters evaluated contained moderate amounts of contaminant and greater than 10% contained heavy amounts. In addition, a survey of over 11,600 engines operating with and without water filters noted a 3 to 1 reduction in water pump seal leakage between fleets using filters and those which do not (SAE Technical Paper Series 881270).The addition of a water filter head and filter is highly recommended.

table 2. six most common problems seen in heavy duty cooling systemsproblem how it happens What can it do prevention

Rust* Oxidation within the system. Clog the system. Cause accelerated wear. The inhibitors in a quality supplemental coolant additive (SCA) prevent the oxidation for rust to occur.

Scale (water hardness)

Present in all tap water are salt minerals, especially calcium and magnesium. These minerals can solidify and adhere to hot metal surfaces.

1. Clog system passages.2. Deposit on high temperature areas and

reduce the heat transfer rate, causing hot spots. This results in uneven metal expansion, scuffing, scoring, accelerated ring wear and eventually, cracked heads and/or blocks.

A quality supplemental coolant additive (SCA) helps to keep salt minerals in suspension so they cannot deposit on engine metal surfaces or clog passages.

Acidity (pH)

1. Glycol antifreeze reacts with oxygen in the air and forms acid.

2. A loose head gasket or other leakage can allow sulfuric acids formed by the burning of fuel to leak into cooling system.

Corrode iron, steel and aluminum. A quality supplemental coolant additive (SCA) neutralizes acids to prevent corrosion.

Pitted cylinderliners

Constant vibration of the cylinder liner causes a momentary vacuum to form on its surface. Coolant boils into the vacuum and vapor bubbles implode on the surfaces of the liner, digging into unprotected liners.

Cause pits which can extend over time, through the thickness of the liner and allow coolant to enter the combustion chamber or crankcase.

A quality supplemental coolant additive (SCA) coats the liner with a thin film to protect it from cavitation erosion without impeding heat transfer.

Foam Foam (the aeration of coolant) occurs from air leakage into the system or low coolant levels.

Adds to the cavitation erosion problem, particularly in the areas of water pump impellers.

A quality supplemental coolant additive (SCA) has an antifoam agent to prevent formation of air bubbles. This foam prevention agent is effective at all temperatures, even during startup.

Pitted waterPump impellers

Flow rates and turbulence are high at the impeller blade. This causes cavitation. In addition, there is a possibility that abrasive particles are present in the system.

Cause loss of pump efficiency and total pump failure.

A quality supplemental coolant additive (SCA) protects the impeller from cavitation erosion and the coolant filter removes particulate matter to reduce abrasive wear on cooling system components.

*It should be noted that rust can appear even within a chemically protected system when oil is present in the coolant. If you do notice the presence of rust, the oil cooler should be inspected for possible leaks.

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b. utilisation with a standard maintenance interval coolant system.

Once an engine has a water filter, either as part of the initial engine or added as described above, it is important to determine the service interval for the equipment. A standard service interval is less than 500 hours, 25,000 mi or 40,000 km. Standard service interval water filters containing SCA can provide the appropriate amount of supplemental coolant additive required to replenish those additives utilized during the service interval.

c. utilisation with a extended maintenance interval coolant system.

Extended Service Interval (ESI) filters are recommended for use up to one year, 250,000 km or 4,000 hours, whichever comes first, on engines with coolant systems up to 20 gal (76 L). For coolant systems above 20 gal (76 L), or if a liquid extender or SCA is used instead of a filter to replenish the SCA, blank water filters are recommended. For Organic Acid Technology (OAT) coolants, blank water filters should be combined with a liquid extender.

ESI water filters are specifically designed to release the proper amount of coolant additive in order to provide the appropriate coolant system protection over time through a coated tablet technology. These tablets are held in a special chamber which prevents the tablets from dissolving too quickly and introducing excess additive into the coolant system.

7. coolant Q&a

Q: Do the liquid and solid additives last the same amount of time?A: Yes, when equivalent amounts of supplemental coolant additives (SCA) are added.

Q: How often should system maintenance be performed?A: This is dependent on the type of SCA you have chosen to use. Refer to engine and additive manufacturer recommendations.

Q: How can I obtain Material Safety Data Sheets (MSDS) for coolant additives?A: MSDS information is available from the coolant additive manufacturer or your filter manufacturer.

Q: Are there environmental hazards to not treating a coolant system properly?A: There are no “environmental” hazards. There are definitely mechanical hazards related to incorrect coolant system maintenance procedures. (Water pump failures, wet sleeve cavitation erosion and premature catastrophic engine failures.)

Q: Why doesn’t a coolant filter come factory installed on some engines?A: Due to various engine designs, some engine and equipment manufacturers do not require coolant filtration. Coolant filtration can be added to these systems to prolong water life and/or aid with coolant maintenance.

Q: Is regular tap water all right to use in coolant systems?A: Most tap water does not meet engine manufacturer’s specifications for use in coolant systems. Please refer to OEM guidelines and consider a coolant analysis program to determine suitability when in question.

Q: How can I convert “normal” additives to extended drain or extended service additives?A: Each additive manufacturer offering extended service interval products can provide advice.

Q: I’ve never had cooling system problems. Why do I need coolant additives and filters? A: It is very rare that a gasoline or diesel engine has “never” experienced a failure of a cooling system component, or a related part that couldn’t have been prevented with the proper use of SCA’s and a coolant filter. Both the short term and the long term economic benefits of properly utilizing SCA’s and coolant filtration far out weigh the low initial investment for the appropriate coolant products and their installation.

Q: How often do I need to monitor the system? How do I control monitoring when vehicles are travelling nationwide? A: Monitoring, or testing, SCA levels are critical to the over all success of any coolant system maintenance program. SCA level monitoring can be done very easily by using coolant testing. Testing should be done at the maintenance interval for the type of SCA being used to determine if more additives are actually needed to accurately track SCA depletion rates. Testing can also be done at any time between maintenance intervals.

Q: Can liquid SCA’s and filters with SCA’s be used together? A: This depends on the total capacity of the cooling system. Most system capacities are of the size that either the liquid SCA or a filter with solid SCA is utilized. In larger capacity systems, however, both products are used for proper maintenance. Initial installation and maintenance instructions should always be consulted for proper product usage.

Q: What is the difference between filters that are the same physical size and have the same thread size? A: The differences in products that “look” alike are whether or not the filter contains SCA and, if it does, the type and the cooling system volume it will treat.

Q: What is the difference between extended drain and extended service products? A: If the SCA has the correct chemical formulation, the time required between total coolant system drain intervals can be extended beyond normal recommended intervals. The maintenance intervals to keep this product working effectively are not extended. Extended service interval products allow the service interval of the SCA to be extended beyond normal.

Q: What is the correct water and antifreeze mixture to be used in coolant systems? A: The ideal mixture is 50% water and 50% antifreeze. The coolant mixture should never contain less than 40% antifreeze or more than 60% antifreeze. The water used must meet engine manufacturer’s guidelines for use in their coolant systems.

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Q: Coolant seems to disappear from my system. Where does it go? A: Coolant can seem to “disappear” from the system due to the lack of a coolant recovery system, evaporation, hose and clamp leakage or seepage, water pumps and/or thermostats not functioning properly, improperly sealed, cracked or broken head gaskets, cracked cylinder heads or engine blocks, and leaking or seeping radiators, heater cores or oil coolers.

Q: Why does my coolant foam? A: Foam in coolant is usually the sign of trapped air in the system, a leak on the suction side of the water pump, an improperly functioning water pump, low or no coolant in the coolant recovery tank, the lack of a coolant recovery system, the coolant system lack of appropriate SCA’s or the combining of incompatible chemicals in the coolant system.

Q: What happens if the coolant system is overcharged with additives? A: Over charging or over concentrating a coolant system with additives will result in the formation of solids. These solids will form deposits that drop out and clog passage ways in the system preventing proper heat transfer. These solids are also very abrasive and will permanently damage surfaces they come in contact with. If a coolant filter is in use, it will be quickly plugged up.

Q: Are additives and filters with additives compatible with long life / extended life coolant? A: Check with additive and coolant manufacturer for recommendations.

Q: What is the best way to determine the freeze point of the coolant? A: The most consistently accurate method to determine the freeze point of the coolant is the use of a refractometer. Alternative test methods can also provide an estimate of freeze point.

Q: How often should I change my antifreeze? A: Antifreeze should be changed based on original equipment engine manufacturer’s recommendations or with the use of full laboratory coolant analysis.

Q: Can I use a liquid SCA in either a gasoline or diesel engine with no coolant filter? A: Yes. However we do recommend the use of an additive free filter on all coolant systems to remove all solid and liquid contamination. Coolant system maintenance should always be done as a complete package to be most effective.

Q: Is it better to use a filter with coolant additive or a liquid SCA with an additive free filter? A: Which coolant maintenance set-up to use is entirely determined by user preference. When properly installed, pre-charged and maintained, both filters with SCA’s and liquid SCA’s used with additive free filters will offer the coolant system identical levels of protection.

Q: Why can’t I use a bigger filter with SCA’s? A: Coolant filters with SCA’s are different physical sizes because they may contain different amounts of additives. The proper amount of SCA to be used to either pre-charge or maintain the additive level

in the coolant is determined by the total capacity of the coolant system. Using the incorrect filter can result in an under-charged or an over-charged system. Both of these situations result in improper coolant system performance and could lead to pre-mature failures.

Q: Will adding SCA’s to a coolant system postpone or cure existing corrosion problems? A: No. If the system is already in poor physical condition, it should be thoroughly cleaned and flushed before the introduction of SCA’s. Once it is clean, the SCA’s will keep it that way provided proper maintenance intervals are followed.

Q: What types of coolant cleaners / flushes should be used? A: Original equipment engine suppliers should be consulted to determine what cleaning/flushing products they recommend for use in their systems

Q: If I change vehicles or equipment, can I use up my existing filters with SCA’s?A: The total capacity of the coolant system is the sole determining factor as to which filter with SCA’s is to be used. If the new system’s capacity matches the usage specifications of the filters you already have, the antifreeze being used is suitable for use with the filters in question and the filters are still in their original factory packaging, they can be used.

Q: How do I find out what the total coolant capacity of my system is? A: The original equipment vehicle, engine or equipment manufacturer has this information available.

Q: Do supplemental coolant products work with recycled antifreeze? A: The vacuum distillation recycling method is the only method accepted by original equipment manufacturers. Some processes return the antifreeze to the customer with SCA’s already added. Before installing any products on the systems using recycled antifreeze, you must know whether it contains any SCA’s. If it does, an additive free filter is all that is needed until the first service interval is reached. At this point to properly treat the system, you must know what type of SCA was used by the recycler.

Q: Do you really need to test between service intervals? A: Yes. Leaks in the system could develop, other components that could allow contamination into the coolant system could fail, foreign substances or incompatible fluids could be introduced to the system or coolant system components such as the thermostat or water pump could fail. All of these situations will directly affect the ability of a properly treated coolant system to perform correctly. Periodic testing with test strips can help avoid the potentially catastrophic results of a system that is not protected.

Q: What does the additive actually do while circulating in the coolant system? A: In a clean, properly treated system, the additive physically coats the metal components and protects them from scale build up, corrosion and cavitation erosion (liner pitting).

Q: Which brand of antifreeze is low silicate type? A: Any antifreeze that meets ASTM D-4985 specifications is considered low silicate antifreeze.

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protection of the cooling system for heavy duty diesel engines · receive maximum protection for your cooling system, ... molybdate, nitrate, nitrite, phosphate, silicate. ... Scale