Section 10 Chapter 15 - dmcpubs.com · Section 10 Chapter 15 7-89440NH 24 Valve, 8.3 Liter Engine Cooling System Note: All coding used in the 8.3 Liter and 9 Liter engine manuals

Section 10 Chapter 15

7-89440NH

24 Valve, 8.3 Liter Engine

Cooling System

Note: All coding used in the 8.3 Liter and 9 Liter engine manuals are Cummins engine codes. These engine codes have no meaning to New Holland warranty codes and should only be used for procedure

steps.

24 Valve, 8.3 Liter EngineCooling System Page a

7-89440NH Section 10 Chapter 15 Issued 8-2001

Cooling System

Contents

Coolant Filter (008-006) ................................................................................................................................................................................. 5Install (008-006-026) ........................................................................................................................................................................ 6Remove (008-006-002) .................................................................................................................................................................... 5

Coolant Filter Head (008-007) ....................................................................................................................................................................... 6Clean (008-007-006) ........................................................................................................................................................................ 7Install (008-007-006) ........................................................................................................................................................................ 7Remove (008-007-002) .................................................................................................................................................................... 6

Coolant Filter Valve (008-009) ....................................................................................................................................................................... 8Install (008-009-026) ........................................................................................................................................................................ 9Remove (008-009-002) .................................................................................................................................................................... 8

Coolant Heater (008-011) ............................................................................................................................................................................. 10Clean (008-011-006) ...................................................................................................................................................................... 10Install (008-011-026) ...................................................................................................................................................................... 11Preparatory (008-011-000) ............................................................................................................................................................. 10Remove (008-011-002) .................................................................................................................................................................. 10

Coolant Temperature Gauge (008-004) ........................................................................................................................................................ 5General Information ......................................................................................................................................................................... 5Initial Check (008-004-001).............................................................................................................................................................. 5

Coolant Thermostat (008-013) .................................................................................................................................................................... 12Clean (008-013-006) ...................................................................................................................................................................... 12General Information ....................................................................................................................................................................... 12Inspect for Reuse (008-013-007) ................................................................................................................................................... 13Install (008-013-026) ...................................................................................................................................................................... 15Leak Test (008-013-014) ................................................................................................................................................................ 13Remove (008-013-002) .................................................................................................................................................................. 12

Cooling System (008-018) ........................................................................................................................................................................... 16General Information ....................................................................................................................................................................... 16

Drive Belt, Cooling Fan (008-002) ................................................................................................................................................................. 4Inspect for Reuse (008-002-007) ..................................................................................................................................................... 4Install (008-002-026) ........................................................................................................................................................................ 4Remove (008-002-002) .................................................................................................................................................................... 4

Fan Clutch, On-Off (008-027) ...................................................................................................................................................................... 20General Information ....................................................................................................................................................................... 20

Fan Shroud Assembly (008-038) ................................................................................................................................................................ 20General Information ....................................................................................................................................................................... 20Initial Check (008-038-001) ............................................................................................................................................................ 21

Fan Spacer and Pulley (008-039) ................................................................................................................................................................ 21Remove (008-039-002) .................................................................................................................................................................. 21

24 Valve, 8.3 Liter EnginePage b Cooling System


Fan, Cooling (008-040) ................................................................................................................................................................................ 22Inspect for Reuse (008-040-007) ................................................................................................................................................... 22Install (008-040-026) ...................................................................................................................................................................... 23Remove (008-040-002) .................................................................................................................................................................. 22

Flow Diagram, Cooling System .................................................................................................................................................................... 1

Radiator (008-042) ........................................................................................................................................................................................ 24General Information ....................................................................................................................................................................... 24Initial Check (008-042-001) ............................................................................................................................................................ 24

Radiator Hoses (008-045) ............................................................................................................................................................................ 25Inspect for Reuse (008-045-007) ................................................................................................................................................... 25

Radiator Pressure Cap (008-047) ............................................................................................................................................................... 25General Information ....................................................................................................................................................................... 25Inspect for Reuse (008-047-007) ................................................................................................................................................... 26

Specifications ................................................................................................................................................................................................ 3Cooling System ................................................................................................................................................................................ 3

Water Pump (008-062) ................................................................................................................................................................................. 26General Information ....................................................................................................................................................................... 26Inspect for Reuse (008-062-007) ................................................................................................................................................... 28Install (008-062-026) ...................................................................................................................................................................... 28Preparatory (008-062-000) ............................................................................................................................................................ 27Remove (008-062-002) .................................................................................................................................................................. 28

24 Valve, 8.3 Liter Engine Flow Diagram, Cooling SystemCooling System Page 1


Flow Diagram, Cooling SystemThe following illustration identifies the significant features of the cooling system.

1. Coolant is drawn from the radiator by the integrally mounted water pump. The output from the water pump empties into the oil cooler cavity of the cylinder block.

2. The coolant then circulates around each cylinder and crosses the block to the fuel pump side of the engine.3. Coolant then flows up into the cylinder head, crosses over the valve bridges and down the exhaust manifold

side of the engine to the integral thermostat housing.4. As the coolant flows across the head toward the thermostat housing, it provides coolant for the injector. When

the engine is below operating temperature, the thermostat is closed, and the coolant flow bypasses the radiator and goes to the water pump inlet through internal drillings in the block.

When operating temperature is reached, the thermostat opens, blocking the bypass passage to the water pump andopening the outlet to the radiator.

� CAUTION �Never operate the engine without a thermostat. Without a thermostat, the coolant will not flow to the radiatorand the engine will overheat.

Flow Diagram, Cooling System 24 Valve, 8.3 Liter EnginePage 2 Cooling System


1. Coolant Inlet from Radiator2. Water Pump Suction3. Coolant Flow through Lubricating Oil Cooler 4. Block Lower Water Manifold (to cylinders)5. Coolant Filter Inlet 6. Coolant Filter Outlet7. Coolant Supply To Cylinder Head8. Coolant Return from Cylinder Head9. Block Upper Water Manifold10. Thermostat Bypass11. Coolant Return to Radiator

24 Valve, 8.3 Liter Engine SpecificationsCooling System Page 3


Specifications

Cooling System

Coolant Capacity (Engine Only) ............................................................................................. 10.9 liters [11.5 qt]

Standard Modulating Thermostat- Range ................................................................ 84° to 91°C [180° to 195° F]

Maximum Allowable Operating Temperature ................................................................................ 100°C [212°F]

Minimum Recommended Operating Temperature .......................................................................... 70°C [158°F ]

Minimum Recommended Pressure Cap .................................................................................... 103 kPa [15 psi]

Drive Belt, Cooling Fan (008-002) 24 Valve, 8.3 Liter EnginePage 4 Cooling System


Drive Belt, Cooling Fan (008-002)

Remove (008-002-002)

3/8-Inch Square Drive

Lift the tensioner to remove the drive belt.

NOTE: The belt tensioner is spring loaded and must bepivoted away from the drive belt. Pivoting in the wrong di-rection can result in damage to the belt tensioner.

Inspect for Reuse (008-002-007)

Inspect the belt for:

• Cracks• Glazing• Tears or cuts• Excessive wear.

Inspect the drive belt pulleys and idlers for cracked or bro-ken grooves. Refer to the following sections if a pulley oridler is damaged:

• Inspect fan pulley. Refer to Procedure 008-039.• Inspect crankshaft pulley. Refer to Procedure 001-

052.• Inspect alternator drive belt. Refer to Procedure 013-

005. • Inspect water pump idler. Refer to Procedure 008-

062.• Belt tensioner idler. Refer to Procedure 013-021.

Install (008-002-026)


Lift and hold the belt tensioner. Install the drive belt and re-lease the tensioner.


24 Valve, 8.3 Liter Engine Coolant Temperature Gauge (008-004)Cooling System Page 5


Coolant Temperature Gauge (008-004)

General Information

Gauges and sensors are used in the system to measurethe coolant temperature. These can malfunction and pro-vide an incorrect temperature reading.

The coolant temperature sensor used by the engine con-trol system is discussed in Procedure 019-019 of the 24Valve, 8.3 Liter, Fuel System Troubleshooting and RepairManual.

Initial Check (008-004-001)

Check for a blown fuse.

Check the wiring from the gauge to the sending unit for abroken connection.

Refer to the vehicle service manual.

Use a temperature gauge of known accuracy to check theexisting gauge.

Replace a faulty gauge or sending unit.

Coolant Filter (008-006)

Remove (008-006-002)

Turn the shutoff valve to the OFF position.

Remove and discard the coolant filter.

Clean the gasket surface.

Coolant Filter Head (008-007) 24 Valve, 8.3 Liter EnginePage 6 Cooling System


Install (008-006-026)� CAUTION �

Do not allow oil to get into the filter. Oil will damagethe DCA.

� CAUTION �Mechanical overtightening can distort the threads ordamage the filter head.

Apply a thin film of lubricating oil to the gasket sealing sur-face before installing the new coolant filter.

Install the coolant filter on the filter head. Tighten the filteruntil the gasket contacts the filter head surface.

Tighten the coolant filter an additional 1/2 to 3/4 of a turn,or as specified by the filter manufacturer.

� CAUTION �The valve must be in the ON position to prevent en-gine damage.

Open the shutoff valve and install the coolant systempressure cap.

Operate the engine and check for coolant leaks.

After the air has been purged from the system, check thecoolant level again.

Coolant Filter Head (008-007)

Remove (008-007-002)� WARNING �

Some coolants are toxic. Keep away from childrenand pets. Dispose in a accordance with local environ-mental regulations.

Drain at least three gallons of coolant from the coolingsystem. Refer to Procedure 008-018.

Remove the coolant filter. Refer to Procedure 008-006.

24 Valve, 8.3 Liter Engine Coolant Filter Head (008-007)Cooling System Page 7


Loosen the four filter head capscrews.

Remove the filter head and gasket.

Clean (008-007-006)

Clean the mating surfaces.

Install (008-007-006)

Install a new gasket and the filter head.

Tighten the four capscrews.

Install the coolant filter. Refer to Procedure 008-006.

Torque Value: 24 N•m [18 ft-lb]

Fill the cooling system with either a 50/50 mixture of goodquality water and fully formulated antifreeze or fully formu-lated coolant. The fully formulated antifreeze or coolantmust meet TMC RP329 or TMC RP330 specifications.

Coolant Filter Valve (008-009) 24 Valve, 8.3 Liter EnginePage 8 Cooling System


Operate the engine and check for leaks.

Coolant Filter Valve (008-009)

Remove (008-009-002)

Remove the coolant filter head. Refer to Procedure 008-007.

Loosen the shutoff valve screw from the end of the valve.

Remove the two pieces of the shutoff valve from bothsides of the valve bore.

24 Valve, 8.3 Liter Engine Coolant Filter Valve (008-009)Cooling System Page 9


Install (008-009-026)

Replace the shutoff valve o-rings.

Lubricate the o-rings before installing the valve piecesback into the bore.

Tighten the shutoff valve screw to tighten the two piecesof the valve together.

Install the coolant filter head on the engine. Refer to Pro-cedure 008-007.

Install the coolant filter. Refer to Procedure 008-006.

Fill the cooling system with either a 50/50 mixture of goodquality water and fully formulated antifreeze or fully formu-lated coolant. The fully formulated antifreeze or coolantmust meet TMC RP329 or TMC RP330 specifications.

Coolant Heater (008-011) 24 Valve, 8.3 Liter EnginePage 10 Cooling System



Coolant Heater (008-011)

Preparatory (008-011-000)

Drain at least 19 liters [5 U.S. gal] of coolant. Refer to Pro-cedure 008-018.

Disconnect the block heater electrical cord.

Remove (008-011-002)

1-1/8 Inch

Loosen the block heater and remove it from the block.

Clean (008-011-006)

Clean the heater threads thoroughly.

24 Valve, 8.3 Liter Engine Coolant Heater (008-011)Cooling System Page 11


Install (008-011-026)

Lubricate the new heater with clean engine oil.

1-1/8 Inch

Install the heater.


Attach the heater electrical cord.


Coolant Thermostat (008-013) 24 Valve, 8.3 Liter EnginePage 12 Cooling System


Coolant Thermostat (008-013)

General Information

The thermostat controls the coolant temperature. Whenthe coolant temperature is below operating temperature,coolant is bypassed to the inlet of the water pump. Whenthe coolant temperature reaches the operating range, thethermostat opens, sealing off the bypass, forcing coolantto flow to the radiator. The thermostat begins opening at82°C [180°F].

� CAUTION �Never operate the engine without a thermostat. With-out a thermostat, the path of least resistance for thecoolant is through the bypass to the pump inlet. Thiswill cause the engine to overheat.

An incorrect or malfunctioning thermostat can cause theengine to run too hot or too cold.

Remove (008-013-002)

10 mm

Remove the water outlet tube capscrews and water outlettube. Refer to Procedure 008-014.

Remove the thermostat.

Clean (008-013-006)

Clean all mating surfaces.

NOTE: Do not let any debris fall into the thermostat cavitywhen cleaning the surfaces.

24 Valve, 8.3 Liter Engine Coolant Thermostat (008-013)Cooling System Page 13



Inspect the thermostat for damage.

NOTE: Do not allow the thermostat or thermometer totouch the container.

Heat the water and check the thermostat as follows:

Suspend the thermostat and a 100°C [212°F] thermome-ter in a container of water.

The nominal operating temperature is stamped on thethermostat. The thermostat must meet the following crite-ria:

• The thermostat must begin to open within 1°C [2°F] of this nominal temperature.

• The thermostat must be fully open within 12°C [22°F] of this nominal temperature.

The fully open distance between the thermostat flangeand housing is 9.4 mm [0.370 in].

Leak Test (008-013-014)

The engine thermostat and thermostat seal must operateproperly in order for the engine to operate in the most ef-ficient heat range. Overheating or overcooling will shortenengine life.

Coolant Thermostat (008-013) 24 Valve, 8.3 Liter EnginePage 14 Cooling System


� WARNING �Complete this test with the engine coolant tempera-ture below 49°C [120°F]. Hot steam can cause seriouspersonal injury.

Remove the radiator hose from the thermostat housing.

Use an electronic service tool to monitor the coolant tem-perature. Install a thermocouple or temperature gauge,which is known to be accurate, in the water heater plateon the engine side of the thermostat housing.

Install a hose of the same size on the thermostat housingoutlet long enough to reach a remote dry container usedto collect coolant.

Install and tighten a hose clamp on the housing outlet.

Place the other end of the hose in a dry container.

Operate the engine at rated speed for 1 minute.

Shut off the engine and measure the amount of coolantcollected in the container.

The amount of coolant collected must not be more than100 cc [3.3 fl. oz.].

24 Valve, 8.3 Liter Engine Coolant Thermostat (008-013)Cooling System Page 15


If more than 100 cc [3.3 fl. oz.] of coolant is collected, thethermostat is leaking and must be replaced.

Complete the following test in-chassis to determine thethermostat opening temperature.

Start the engine and monitor the water temperature withan electronic service tool or a gauge. Keep the enginespeed below 1500 rpm during the test.

Shut off the engine when the coolant starts to flow.

If coolant does not start flowing into the container duringthe initial opening temperature range, the thermostatmust be replaced. Refer to Procedure 008-013.

Install (008-013-026)

Install the new thermostat into the thermostat housing.Make sure the top and bottom o-rings are in place.

Thermostat Initial Opening Temperature°C °F81 MIN 17883 MAX 182

Cooling System (008-018) 24 Valve, 8.3 Liter EnginePage 16 Cooling System


10 mm

Install the water outlet tube and capscrews.


� CAUTION �Be sure to vent the engine and aftercooler during fill-ing, to remove air from the coolant system or over-heating will result.

Fill the cooling system.


Cooling System (008-018)

General Information

The function of the cooling system is to maintain a speci-fied operating temperature for the engine. Some of theheat generated by the engine is absorbed by the coolantflowing through the passages in the cylinder block andhead. Then, heat is removed from the coolant as it flowsthrough the radiator.

The accompanying chart illustrates the coolant flowthrough the engine. For more detail, refer to the coolantflow diagrams.

1. Water pump2. Engine block, oil cooler, cylinder head, other acces-

sories (e.g., heater core)3. Thermostat4. Radiator

24 Valve, 8.3 Liter Engine Cooling System (008-018)Cooling System Page 17


Open the petcocks at the bottom of the radiator and at thebottom of the oil cooler housing. Remove the lower radia-tor hose. A 20 liter [4 U.S. gallons] drain pan will containthe coolant in most applications.

When you troubleshoot overheating, remember that toomuch oil in the oil pan can cause additional heat from fric-tion when the rod journals are submerged in oil. Overfillingwith oil raises the oil temperature that is transferred to thecooling system at the oil cooler.

The system is designed to use a specific quantity of cool-ant. If the coolant level is low, the engine will run hot.

NOTE: The engine or system has a leak if frequent addi-tion of coolant is necessary. Find and repair the leak.

� CAUTION �The engine coolant passages must be completelyfilled with coolant.

During operation, entrapped air mixes with the coolant,which results in cavitation corrosion and poor heat trans-fer. Highly aerated coolant can cause localized overheat-ing of the cylinder head and block that can result in acracked head, scored cylinder liner, or blown head gasket.

Cooling System (008-018) 24 Valve, 8.3 Liter EnginePage 18 Cooling System


Obstructions in the coolant passages will reduce coolantflow, which can lead to overheating.

NOTE: The small holes in the head gasket are especiallysusceptible to plugging. Their size is critical. Do not en-large the size of the orifices. To do so will disturb the cool-ant flow and will not solve an overheating problem.

� CAUTION �Never use water alone for coolant. Damage from cor-rosion can result.

Water will cause rust formation, reducing the flow in thesmaller coolant passages.

Also, water used as a coolant for even a relatively shortperiod can result in the expansion plugs rusting through,which will allow the coolant to leak.

NOTE: A sudden loss of coolant from a heavily loaded en-gine can result in severe damage to the pistons and cylin-der bore.

Overfueling and Loading

� CAUTION �Overfueling can cause the engine to overheat. Makesure that the correct engine electronic control module(ECM) calibration is being used.

� CAUTION �Constant overloading (lugging) can cause the engineto run hot.

24 Valve, 8.3 Liter Engine Cooling System (008-018)Cooling System Page 19


Fully Formulated Coolant/Antifreeze

CDC recommends using either a 50/50 mixture of goodquality water and fully formulated antifreeze, or fully for-mulated coolant when filling the cooling system. The fullyformulated antifreeze or coolant must meet TMC RP329or TMC RP330 specifications.

Good quality water is important for cooling system perfor-mance. Excessive levels of calcium and magnesium con-tribute to scaling problems, and excessive levels ofchlorides and sulfates cause cooling system corrosion.

Fully formulated antifreeze must be mixed with good qual-ity water at a 50/50 mix (40 to 60 percent working range).A 50/50 mixture of antifreeze and water gives a -36°C [-34°F] freezing point and a boiling point of 110°C [228°F],which is adequate for locations in North America. The ac-tual lowest freezing point of ethylene glycol antifreeze is at68 percent. Using higher concentrations of antifreeze willraise the freezing point of the solution and increase thepossibility of a silicate gel problem.

Cooling System Sealing Additives

Do not use sealing additives in the cooling system. Theuse of sealing additives will:

• Build up in coolant low flow areas• Clog coolant filters• Plug radiator and oil cooler.

Fan Clutch, On-Off (008-027) 24 Valve, 8.3 Liter EnginePage 20 Cooling System


Cooling System Soluble Oils

Do not use soluble oils in the cooling system. The use ofsoluble oils will:

• Corrode brass and copper• Damage heat transfer surfaces• Damage seals and hoses.

Fan Clutch, On-Off (008-027)

General Information

Many fan clutches can be controlled by the engine's elec-tronic control module (ECM). The ECM monitors coolanttemperature and intake manifold temperature to deter-mine when to engage the cooling fan. Some applicationshave additional sensors monitored by the ECM for fancontrol (for example, air conditioner pressure and trans-mission temperature). These are various fan clutch types,such as air engaged, air disengaged, electric, viscous,and ON/OFF. Refer to the equipment manufacturer's ser-vice manual to determine fan clutch type.

The ECM is capable of using either a zero VDC or 12 VDCsignal to engage the fan clutch. The enable logic is con-tained in the ECM calibration and can be programmed us-ing an electronic service tool.

Refer to the vehicle service manual for fan clutch trouble-shooting and repair information.

Fan Shroud Assembly (008-038)

General Information

The radiator or fan shroud is used to direct all air flowacross the radiator fins rather than around the edges ofthe radiator.

An incorrect fan shroud or obstructions can reduce air flowand cause the engine to run hot.

NOTE: Check to be sure air is not recirculating. Check formissing baffles.

24 Valve, 8.3 Liter Engine Fan Spacer and Pulley (008-039)Cooling System Page 21



� CAUTION �The fan shroud must be installed correctly, be in goodcondition, and the shroud to fan clearance must bewithin the manufacturer's specifications to ensureproper air flow through the radiator to provide ade-quate engine cooling.

Inspect the fan shroud for proper fan clearance, cracks, airleaks, and damage. Replace if necessary.

CDC recommends that fan clearance be between 5.08 to10.16 cm [2 to 4 in] from the radiator core.

Fan Spacer and Pulley (008-039)

Remove (008-039-002)


Lift the tensioner to relieve tension in the belt. Remove thebelt. Refer to Procedure 008-002.


15 mm

Remove the fan capscrews, fan, and spacer.

Remove the fan pulley.

Fan, Cooling (008-040) 24 Valve, 8.3 Liter EnginePage 22 Cooling System


Install (008-039-026)

15 mm

Install the fan pulley.

Install the spacer, fan, and fan capscrews.

Torque Value: 51 to 62 N•m [37 to 45 ft-lb]


Lift the tensioner and install the belt. Refer to Procedure008-002.

Service Tip: If difficulty is experienced installing the drivebelt (i.e., the belt seems too short), position the belt overthe grooved pulleys first and then, while holding the ten-sioner up, slide the belt over the water pump pulley.

Fan, Cooling (008-040)

Remove (008-040-002)

15 mm

Remove the fan capscrews, the fan, and spacer.


� WARNING �Do not rotate the engine by pulling or prying on thefan. The fan blade(s) can be damaged and cause thefan to fail and cause serious personal injury or prop-erty damage. Use the engine barring gear to rotate thecrankshaft.

24 Valve, 8.3 Liter Engine Fan, Cooling (008-040)Cooling System Page 23


Inspect the cooling fan daily. Check for cracks, loose riv-ets, and bent or loose blades. Check the fan to make sureit is securely mounted. Tighten the capscrews if neces-sary.

� WARNING �Do not straighten a bent fan blade or continue to usea damaged fan. A bent or damaged fan blade can failduring operation and cause serious personal injury orproperty damage.

Replace any fan that is damaged with a fan of the identicalpart number. CDC must approve any other fan changes.

Install (008-040-026)

15 mm

Install the spacer, fan, and fan capscrews.

Torque Value: 51 to 62 N•m [37 to 45 ft-lb]

Radiator (008-042) 24 Valve, 8.3 Liter EnginePage 24 Cooling System


Radiator (008-042)

General Information

Air forced through the fins of the radiator by a fan cools thecoolant pumped through the radiator. Environmental de-bris (such as paper, straw, lint, and dust) can obstruct thefins and stop the flow of air that will reduce the cooling ef-fect of the radiator.


� CAUTION �Wear appropriate eye and face protection when usingcompressed air. Improper use can cause bodily injuryfrom flying debris and dirt.

Inspect for plugged radiator fins.

Use compressed air to blow out the dirt and debris.

Air Pressure: 552 kPa [80 psi]

Inspect for bent or broken fins.

Inspect for radiator core and gasket leaks.

If the radiator must be replaced, refer to the equipmentmanufacturer's replacement procedures.

� WARNING �If a liquid refrigerant system must be removed beforeremoving the radiator, wear eye and face protection.Wrap cloth around the fittings before removal. Liquidrefrigerant can cause serious eye and skin injury.

Recycle refrigerant according to accepted practices.

24 Valve, 8.3 Liter Engine Radiator Hoses (008-045)Cooling System Page 25


Radiator Hoses (008-045)


Inspect all hoses for cracks, cuts, or collapsing.

Radiator Pressure Cap (008-047)

General Information

The system is designed to use a pressure cap to preventboiling of the coolant.

An incorrect or malfunctioning cap can result in the loss ofcoolant and the engine running hot.

Air in the coolant can result in loss of coolant from theoverflow when the aerated coolant is hot. The heated airexpands, increasing the pressure in the system, causingthe cap to open.

Similarly, coolant can be displaced through the overflow ifthe head gasket leaks compression gases to the coolantsystem.

Radiator Cap Pressure Test System Cap

A (Normal Duty) 104°C [220°F] 103 kPa [15 psi]

Water Pump (008-062) 24 Valve, 8.3 Liter EnginePage 26 Cooling System


The operating pressure of the cooling system and the lu-bricating system can result in the mixing of the fluids ifthere is a leak between the systems such as the headgasket or oil cooler. Refer to Section 10, Chapter14, Lubri-cating Oil System.

Transmission fluid can also leak into the coolant throughradiator bottom tank transmission oil coolers.


Be sure the correct radiator cap is being used. Refer toProcedure 008-047, General Information.

Inspect the rubber seal of the pressure cap for damage.

Inspect the radiator fill neck for cracks or other damage.

Refer to the equipment manufacturer's service manual forinstructions if the fill neck is damaged.

Pressure test the radiator cap.

The pressure cap must seal within 14 kPa [2 psi] of thevalue stated on the cap, or it must be replaced.

Refer to the vehicle service manual for radiator cap testprocedure.

Water Pump (008-062)

General Information

The water pump pulls coolant from the bottom of the radi-ator and pumps it through the engine back to the top of theradiator for cooling. Reduced or interrupted flow will resultin the engine running hot.

24 Valve, 8.3 Liter Engine Water Pump (008-062)Cooling System Page 27


The pump is belt driven from the crankshaft pulley. An au-tomatic belt tensioner is used to prevent the belt from slip-ping on the pump pulley. A malfunction of the tensionerwill cause the water pump impeller to rotate at a slowerspeed, reducing the amount of coolant flow.

The coolant flow can also be reduced if the inlet hose tothe water pump collapses. A hose will usually not collapsewhile the engine is running at low speed. Check the hosewhile the engine is running at rated speed.

NOTE: Be sure the engine is warm, a minimum of 90.6°C[195°F], so the thermostat is open.

A worn or malfunctioning water pump will not produce theflow required to prevent the engine from running hot. How-ever, be sure to check the other possibilities indicated inthe Coolant Temperature Above Normal symptom chart inSection TS, Troubleshooting Symptoms, before checkingthe flow or replacing the pump.

Preparatory (008-062-000)

Drain the coolant. Refer to Procedure 008-018.

Remove the drive belt. Refer to Procedure 008-002.



Remove (008-062-002)

13 mm

Remove the water pump capscrews and water pump.

Clean (008-062-002)

Clean the o-ring sealing surface on the water pump hous-ing.


Inspect the water pump housing and impeller for cracks ordamage.

Inspect the water pump weep hole for an indication of asteady leak.

NOTE: A streak or chemical buildup at the weep hole isnot justification for water pump replacement. If a steadyflow of coolant or oil is observed, replace the water pumpwith a new or rebuilt unit.

Install (008-062-026)

Install a new sealing ring into the pump groove.

24 Valve, 8.3 Liter Engine Water Pump (008-062)Cooling System Page 29


13 mm

Install the water pump.



Lift the tensioner and install the belt. Refer to Procedure008-002.

Service Tip: If difficulty is experienced installing the drivebelt (i.e., the belt seems too short), position the belt overthe grooved pulleys first and then, while holding the ten-sioner up, slide the belt over the water pump pulley.

Fill the cooling system. Refer to Procedure 008-018.

Close the drain valves. Install all hoses previously re-moved. Install the pressure cap. Operate the engine untilit reaches a temperature of 80°C [180°F], and check forcoolant leaks.



Documents

Section 10 Chapter 15 - dmcpubs.com · Section 10 Chapter 15 7-89440NH 24 Valve, 8.3 Liter Engine Cooling System Note: All coding used in the 8.3 Liter and 9 Liter engine manuals