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Engine Cooling System: Other Dodge Nitro I

Accessory Drive Belts 37 illustrations ~6367 words

COOLING SYSTEM COMPONENTS

The cooling system consists of

  1. Charge Air Cooler (Turbocharged vehicles only)
  2. 2 Speed Electric Cooling Fan
  3. Engine driven fan with viscous clutch (Diesel Engine)
  4. A aluminum-core radiator with plastic side tanks
  5. Combined Coolant Recover Container/Washer Reservoir (Gas Engine)
  6. Combined coolant pressure bottle/overflow system with pressure cap
  7. Radiator
  8. Water pump
  9. Combination A/C condenser/transmission oil cooler (automatic transmission)
  10. Thermostat
  11. Coolant
  12. Water pump
  13. Hoses and hose clamps

Scheme 29

Scheme 29: OPERATION
Scheme 29: OPERATION
1 - LH CYL. HEAD
2 - AIR BLEED
3 - THERMOSTAT LOCATION
4 - RH CYL. HEAD
5 - RH BANK CYL. BLOCK
6 - LH BANK CYL. BLOCK
7 - COOLANT TEMP. SENSOR

The cooling system regulates engine operating temperature. It allows the engine to reach normal operating temperature as quickly as possible. It also maintains normal operating temperature and prevents overheating.

The cooling system also provides a means of heating the passenger compartment. The cooling system is pressurized and uses a centrifugal water pump to circulate coolant throughout the system.

AERATION

Low coolant level in a cross flow radiator will equalize in both tanks with engine off. With engine running and at operating temperature, the high pressure inlet tank runs full and the low pressure outlet tank drops, resulting in cooling system aeration. Aeration will draw air into the water pump resulting in the following

  1. High reading shown on the temperature gauge.
  2. Loss of coolant flow through the heater core.
  3. Corrosion in the cooling system.
  4. Water pump seal may run dry, increasing the risk of premature seal failure.
  5. Combustion gas leaks into the coolant can also cause aeration.

DEAERATION

Air can only be removed from the system by gathering under the pressure cap. On the next heat up it will be pushed past the pressure cap into the coolant recovery bottle by thermal expansion of the coolant. It then escapes to the atmosphere in the coolant recovery bottle and is replaced with coolant on cool down.

To effectively deaerate the system, multiple thermal cycles of the system may be required.

Note. Deaeration does not occur at engine idle, higher engine speeds are required. Normal driving will deaerate cooling system.

FLOW CHECK-DIESEL

To determine whether coolant is flowing through the cooling system, use the following procedures

  1. If engine is cold, idle engine until normal operating temperature is reached. Then feel the upper radiator hose. If it is hot, coolant is circulating. WARNING: Do not remove the cooling system pressure cap with the system hot and under pressure because serious burns from coolant can occur.
  2. Remove pressure/vent cap when engine is cold, idle engine until thermostat opens, you should observe coolant flow while looking down in the coolant recovery pressure container. Once flow is detected install the pressure/vent cap.

Scheme 30

Scheme 30: ULTRAVIOLET LIGHT METHOD
Scheme 30: ULTRAVIOLET LIGHT METHOD
1 - TYPICAL BLACK LIGHT TOOL

A leak detection additive is available through the parts department that can be added to cooling system. The additive is highly visible under ultraviolet light (black light). Pour one ounce of additive into cooling system. Place heater control unit in HEAT position. Start and operate engine until radiator upper hose is warm to touch. Aim the commercially available black light tool at components to be checked. If leaks are present, black light will cause additive to glow a bright green color.

The black light (1) can be used in conjunction with a pressure tester to determine if any external leaks exist.

Scheme 31

Scheme 31: PRESSURE TESTER METHOD
Scheme 31: PRESSURE TESTER METHOD
1 - TYPICAL COOLING SYSTEM PRESSURE TESTER

The engine should be at normal operating temperature. Recheck the system cold if cause of coolant loss is not located during the warm engine examination.

WARNINGHot, pressurized coolant can cause injury by scalding.

Carefully remove radiator pressure cap from pressure bottle and check coolant level. Push down on cap to disengage it from stop tabs. Wipe inside of filler neck and examine lower inside sealing seat for nicks, cracks, paint, and dirt. Inspect radiator-to- reserve/overflow tank hose for internal obstructions. Insert a wire through the hose to be sure it is not obstructed.

Inspect cams on outside of filler neck. If cams are damaged, seating of pressure cap valve and tester seal will be affected.

Attach pressure tester (7700 or an equivalent) to radiator filler neck.

Operate tester pump (1) to apply 110 kPa (16 psi) pressure to system. If hoses enlarge excessively or bulges while testing, replace as necessary. Observe gauge pointer and determine condition of cooling system according to following criteria

Holds Steady: If pointer remains steady for two minutes, serious coolant leaks are not present in system. However, there could be an internal leak that does not appear with normal system test pressure. If it is certain that coolant is being lost and leaks cannot be detected, inspect for interior leakage or perform Internal Leakage Test.

Drops Slowly: Indicates a small leak or seepage is occurring. Examine all connections for seepage or slight leakage with a flashlight. Inspect radiator, hoses, gasket edges and heater. Seal small leak holes with a Sealer Lubricant (or equivalent). Repair leak holes and inspect system again with pressure applied.

Drops Quickly: Indicates that serious leakage is occurring. Examine system for external leakage. If leaks are not visible, inspect for internal leakage. Large radiator leak holes should be repaired by a reputable radiator repair shop.

RECENT SERVICE OR ACCIDENT REPAIR

  1. Engine adjustments (incorrect timing)
  2. Slipping accessory drive belt
  3. Brakes (possibly dragging)
  4. Changed parts (incorrect water pump)
  5. Reconditioned radiator or cooling system refilling (possibly under filled or air trapped in system). NOTE: If investigation reveals none of the previous items as a cause for an engine overheating complaint, refer to following Cooling System Diagnosis charts.

TRAILER TOWING

Consult Trailer Towing section of owners manual. Do not exceed limits.

These charts are to be used as a quick-reference only.

CONDITIONPOSSIBLE CAUSESCORRECTION
TEMPERATURE GAUGE READS LOW1. Has a Diagnostic Trouble Code (DTC) been set indicating a stuck open thermostat?1. Refer to OPERATION . Replace thermostat if necessary.
2. Is the temperature sending unit connected?2. Check the temperature sensor connector. See DESCRIPTION . Repair connector if necessary.
3. Is the temperature gauge operating OK?3. Check gauge operation. Repair as necessary.
4. Coolant level low in cold ambient temperatures accompanied with poor heater performance.4. Check coolant level in the coolant pressure bottle and the radiator. Inspect system for leaks. Repair leaks as necessary.
5. Improper operation of internal heater doors or heater controls.5. Inspect heater and repair as necessary. Refer to DIAGNOSIS AND TESTING . Refer to DIAGNOSIS AND TESTING .
6. Electric fan functioning when not required.6. Inspect electric fan for proper operation. Refer to Electric Cooling Fan in this section. Refer to group 8W for electric cooling fan and relay circuit schematic data.
TEMPERATURE GAUGE READS HIGH OR THE COOLANT WARNING LAMP ILLUMINATES. COOLANT MAY OR MAY NOT BE LOST OR LEAKING FROM THE COOLING SYSTEM.1. Trailer is being towed, a steep hill is being climbed, vehicle is operated in slow moving traffic, or engine is being idled with very high ambient (outside) temperatures and the air conditioning is on. Higher altitudes could aggravate these conditions.1. This may be a temporary condition and repair is not necessary. Turn off the air conditioning and attempt to drive the vehicle without any of the previous conditions. Observe the temperature gauge. The gauge should return to the normal range. If the gauge does not return to the normal range, determine the cause for overheating and repair.
2. Is the temperature gauge reading correctly?2. Check gauge. (Refer to Group 8J - INSTRUMENT CLUSTER). Repair as necessary.
3. Is the temperature warning illuminating unnecessarily?3. Check warning lamp operation. (Refer to Group 8J - INSTRUMENT CLUSTER). Repair as necessary.
4. Coolant low in coolant pressure bottle and radiator?4. Check for coolant leaks and repair as necessary.
5. Pressure cap not installed tightly. If cap is loose, boiling point of coolant will be lowered. Also refer to the following Step 6.5. Tighten cap.
6. Poor seals at the radiator cap.6. (a) Check condition of cap and cap seals. See DIAGNOSIS AND TESTING .
(b) Check condition of radiator filler neck. If neck is bent or damaged, replace radiator.
7. Coolant not flowing through system.7. (a) Check condition of pressure bottle cap and cap seals. See DIAGNOSIS AND TESTING .
(b) Check condition of the hose from the radiator to the coolant tank. It should fit tight at both ends without any kinks or tears. Replace hose if necessary.
(c) Check pressure bottle/overflow tank and tank's hoses for blockage. Repair as necessary.
8. Incorrect coolant concentration8. Check coolant. See COOLANT-DESCRIPTION for correct coolant/water mixture ratio.
9. Radiator or A/C condenser fins are dirty or clogged.9. Remove insects and debris.
10. Radiator core is corroded or plugged.10. Replace radiator.
11. Fuel or ignition system problems.11. Refer to FUEL or IGNITION CONTROL for diagnosis.
12. Dragging brakes.12. Check and correct as necessary. Refer to DIAGNOSIS AND TESTING . Refer to DIAGNOSIS AND TESTING . Refer to DIAGNOSIS AND TESTING . for correct procedures.
13. Bug screen or cardboard is being used, reducing airflow.13. Remove bug screen or cardboard.
14. Thermostat partially or completely shut.14. Check thermostat operation and replace as necessary. See REMOVAL .
15. Viscous fan drive not operating properly.15. Check fan drive operation and replace as necessary. See DIAGNOSIS AND TESTING .
16. Cylinder head gasket leaking.16. Check for cylinder head gasket leaks. See DIAGNOSIS AND TESTING . For repair, . Refer to REMOVAL . Refer to REMOVAL .
17. Heater core leaking.17. Check heater core for leaks. Refer to REMOVAL . Repair as necessary.
18. Electric fan not functioning.18. Inspect electric fan for proper operation. See DIAGNOSIS AND TESTING .
TEMPERATURE GAUGE READING IS INCONSISTENT (FLUCTUATES, CYCLES OR IS ERRATIC)1. During cold weather operation, with the heater blower in the high position, the gauge reading may drop slightly.1. A normal condition. No correction is necessary.
2. Temperature gauge or engine mounted gauge sensor defective or shorted. Also, corroded or loose wiring in this circuit.2. Check operation of gauge and repair if necessary. Refer to DIAGNOSIS AND TESTING . Refer to DIAGNOSIS AND TESTING .
3. Gauge reading rises when vehicle is brought to a stop after heavy use (engine still running).3. A normal condition. No correction is necessary. Gauge should return to normal range after vehicle is driven.
4. Gauge reading high after re-starting a warmed up (hot) engine.4. A normal condition. No correction is necessary. The gauge should return to normal range after a few minutes of engine operation.
5. Coolant level low in cooling system (air build up in the cooling system causing the thermostat to open late).5. Check and correct coolant leaks. See DIAGNOSIS AND TESTING .
6. Cylinder head gasket leaking allowing exhaust gas to enter cooling system causing a thermostat to open late.6. (a) Check for cylinder head gasket leaks. Refer to engine sections.
(b) Check for coolant in the engine oil. Inspect for white steam emitting from the exhaust system. Repair as necessary.
7. Water pump impeller loose on shaft.7. Check water pump and replace as necessary.
8. Loose accessory drive belt.8. See DIAGNOSIS AND TESTING . Check and correct as necessary.
9. Air leak on the suction side of the water pump allows air to build up in cooling system causing thermostat to open late.9. Locate leak and repair as necessary.
PRESSURE CAP IS BLOWING OFF STEAM OR COOLANT TO COOLANT RECOVERY CONTAINER. TEMPERATURE GAUGE READING MAY BE ABOVE NORMAL BUT NOT HIGH. COOLANT LEVEL MAY BE HIGH IN COOLANT RECOVERY CONTAINER.1. Pressure relief valve in radiator pressure cap is defective.1. Check condition of radiator cap and cap seals. See DIAGNOSIS AND TESTING . Replace cap as necessary.
2. Overfilled cooling system or extremely low coolant level.2. Wait for engine to cool and adjust coolant level.
COOLANT LOSS TO THE GROUND WITHOUT PRESSURE CAP BLOWOFF. GAUGE READING HIGH OR HOT1. Coolant leaks in radiator, cooling system hoses, water pump or engine.1. Pressure test and repair as necessary. See DIAGNOSIS AND TESTING .
DETONATION OR PRE-IGNITION (NOT CAUSED BY IGNITION SYSTEM). GAUGE MAY OR MAY NOT BE READING HIGH1. Engine overheating.1. Check reason for overheating and repair as necessary.
2. Freeze point of coolant not correct. Mixture is too rich or too lean.2. Check coolant concentration. See COOLANT-DESCRIPTION and adjust ratio as required.
HOSE OR HOSES COLLAPSE WHILE ENGINE IS RUNNING1. Vacuum created in cooling system on engine cool-down is not being relieved through coolant reserve/overflow system.1. (a) Radiator cap relief valve stuck. See DIAGNOSIS AND TESTING . Replace if necessary.
(b) Hose between coolant reserve/overflow tank and radiator is kinked. Repair as necessary.
(c) Vent at coolant reserve/overflow tank is plugged. Clean vent and repair as necessary.
(d) Reserve/overflow tank is internally blocked or plugged. Check for blockage and repair as necessary.
INADEQUATE HEATER PERFORMANCE.1. Has a Diagnostic Trouble Code (DTC) been set?1. Refer to Section 25 - EMISSIONS CONTROL
2. Coolant level low.2. See DIAGNOSIS AND TESTING .
3. Obstructions in heater hose/fittings.3. Remove heater hoses at both ends and check for obstructions.
4. Heater hose kinked.4. Locate kinked area and repair as necessary.
5. Water pump is not pumping water to/through the heater core. When the engine is fully warmed up, both heater hoses should be hot to the touch. If only one of the hoses is hot, the water pump may not be operating correctly or the heater core may be plugged. Accessory drive belt may be slipping causing poor water pump operation.5. If a slipping belt is detected, see REMOVAL . If heater core obstruction is detected, . See STANDARD PROCEDURE for cooling system reverse flushing.
STEAM IS COMING FROM THE FRONT OF VEHICLE NEAR THE GRILLE AREA WHEN WEATHER IS WET, ENGINE IS WARMED UP AND RUNNING, AND VEHICLE IS STATIONARY. TEMPERATURE GAUGE IS IN NORMAL RANGE1. During wet weather, moisture (snow, ice or rain condensation) on the radiator or condenser will evaporate when the thermostat opens. This opening allows heated water into the radiator. When the moisture contacts the hot radiator or condenser, steam may be emitted. This usually occurs in cold weather with no fan or airflow to blow it away.1. Occasional steam emitting from this area is normal. No repair is necessary.
COOLANT COLOR1. Coolant color is not necessarily an indication of adequate corrosion or temperature protection. Do not rely on coolant color for determining condition of coolant.1. See COOLANT-DESCRIPTION for coolant concentration information. Adjust coolant mixture as necessary.
COOLANT LEVEL CHANGES IN COOLANT RESERVE/OVERFLOW TANK. TEMPERATURE GAUGE IS IN NORMAL RANGE1. Level changes are to be expected as coolant volume fluctuates with engine temperature. If the level in the tank was between the FULL and ADD marks at normal operating temperature, the level should return to within that range after operation at elevated temperatures.1. A normal condition. No repair is necessary.
FAN RUNS ALL THE TIME1. Fan control sensors inoperative.1. Check for DTCs. Verify sensor readings.
2. Transmission temperature too high.2. Check for transmission over temp DTC.
3. Engine coolant temperature too high.3. (a) Check coolant level. Correct level as required.
(b) Thermostat stuck. Replace thermostat.
(c) Water pump failed. Replace water pump.
(d) Coolant flow restricted. Clean radiator.
(e) Air flow over radiator obstructed. Remove obstruction.
4. ECM or TIPM defective.4. Replace ECM or TIPM

CHEMICAL CLEANING

If visual inspection indicates the formation of sludge or scaly deposits, use a radiator cleaner (Mopar® Radiator Kleen or equivalent) before flushing. This will soften scale and other deposits and aid the flushing operation.

CAUTIONBe sure instructions on the container are followed.

FILLING-DIESEL

  1. Tighten the radiator draincock and the cylinder block drain plug(s) (if removed). CAUTION: Failure to purge air from the cooling system can result in an overheating condition and severe engine damage.
  2. Fill cooling system with the antifreeze mixture. Refer to «DESCRIPTION»(ref-306134-S06534103112008120900000) . Fill pressure bottle to service line and install cap. NOTE: The engine cooling system will push any remaining air into the coolant bottle within about an hour of normal driving. As a result, a drop in coolant level in the pressure bottle may occur. If the engine cooling system overheats and pushes coolant into the overflow side of the coolant bottle, this coolant will be sucked back into the cooling system ONLY IF THE PRESSURE CAP IS LEFT ON THE BOTTLE. Removing the pressure cap breaks the vacuum path between the two bottle sections and the coolant will not return to cooling system.
  3. With heater control unit in the HEAT position, operate engine with pressure bottle cap in place.
  4. Add coolant to pressure bottle as necessary. Only add coolant to the pressure bottle when the engine is cold. Coolant level in a warm engine will be higher due to thermal expansion.

Note. The coolant bottle has two chambers. Coolant will normally only be in the outboard (larger) of the two. The inboard chamber is only to recover coolant in the event of an overheat or after a recent service fill. The inboard chamber should normally be empty. If there is coolant in the overflow side of the coolant bottle (after several warm/cold cycles of the engine) and coolant level is above cold full when cold, disconnect the end of the overflow hose at the fill neck and lower it into a clean container. Allow coolant to drain into the container until emptied. Reconnect overflow hose to fill neck.

FILLING-GAS

Remove radiator pressure cap and fill system, using 50/50 mixture of the appropriate fluid and distilled water. Refer to DESCRIPTION .

Continue filling system until full. Do not spill coolant on drive belts or the generator. For cooling system capacity, refer to SPECIFICATIONS .

Fill coolant recovery/reserve container to at least the MAX mark. It may be necessary to add coolant to the recovery/reserve container after three or four warm up/cool down cycles to maintain coolant level between the MAX and MIN mark. This will allow trapped air to be removed from the system.

FILL VOLUMES

DESCRIPTIONSPECIFICATION
MetricUS
2.8L Diesel12.5 L11.8 qts
3.7L13.2L14.0 qts.
4.0L13.2 L14.0 qts.

CLEANING

Clean all foreign debris from belt pulley grooves. The belt pulleys must be free of oil, grease, and coolants before installing the drive belt.

2.8L DIESEL

1 - WITH A/C
2 - WITHOUT A/C

Scheme 32

Scheme 32
Scheme 32
  1. Check condition of all pulleys. CAUTION: When installing the accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction.
  2. Install accessory drive belt. Route the belt around all pulleys (1 or 2) except the idler pulley.
  3. Rotate the tensioner arm until it contacts its stop position. Route the belt around the idler and slowly let the tensioner rotate into the belt. Make sure the belt is seated onto all pulleys.
  4. Remove the drift from the belt tensioner.

Scheme 33

Scheme 33: 3.7L
Scheme 33: 3.7L
1 - AUTOMATIC TENSIONER ASSEMBLY
  1. Check condition of all pulleys. CAUTION: When installing the accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction.
  2. Install new belt. Route the belt around all pulleys except the idler pulley. Rotate the tensioner arm (1) until it contacts its stop position. Route the belt around the idler and slowly let the tensioner rotate into the belt. Make sure the belt is seated onto all pulleys.
  3. With the drive belt installed, inspect the belt wear indicator. On 3.7L Engines the gap between the tang and the housing stop (measurement A) must not exceed 24 mm (0.94 inches).
  4. Install combination washer reservoir/coolant recovery container. See «INSTALLATION»(ref-306154-S03099954612008120900000) .

4.0L

1 - GENERATOR
2 - IDLER PULLEY
3 - WATER PUMP PULLEY
4 - CRANKSHAFT PULLEY
5 - ACCESSORY DRIVE BELT TENSIONER
6 - A/C COMPRESSOR
7 - ACCESSORY DRIVE BELT

Note. When installing accessory drive belt onto pulleys, make sure that belt is properly routed and all V-grooves make proper contact with pulleys.

  1. Rotate tensioner clockwise and position accessory drive belt over all pulleys.
  2. Gently release tensioner.
  3. Install combination coolant recovery/washer reservoir. See «INSTALLATION»(ref-306154-S03099954612008120900000) .

Scheme 34

Scheme 34: REMOVAL
Scheme 34: REMOVAL
1 - POWER STEERING BELT
2 - POWER STEERING PULLEY
3 - ACCESS HOLE
4 - CRANKSHAFT PULLEY
  1. Remove accessory drive belt. See «REMOVAL»(ref-306154-S30160988302008120900000) .
  2. Position suitable tool between power steering belt (1) and power steering pulley (2) at the top of the pulley.
  3. Use a socket and ratchet to rotate the crankshaft clockwise.
  4. While rotating the crankshaft clockwise, walk the power steering belt (1) off of the power steering pulley (2).
  1. Disconnect negative battery cable.
  2. Remove accessory drive belt (9). see scheme 25 See «REMOVAL»(ref-306154-S30160988302008120900000).
  3. Remove belt tensioner retaining bolt and remove tensioner (1).

Scheme 35

Scheme 35: 3.7L
Scheme 35: 3.7L
1 - TIMING CHAIN COVER
2 - BOLT TORQUE TO 41 N.m (30 FT LBS)
3 - AUTOMATIC BELT TENSIONER
  1. Remove accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL).
  2. Remove tensioner assembly (3) from engine front cover. WARNING: Because of high spring tension, do not attempt to disassemble automatic tensioner. Unit is serviced as an assembly (except for pulley on tensioner).
  3. Remove pulley bolt. Remove pulley from tensioner.

Scheme 36

Scheme 36: 4.0L
Scheme 36: 4.0L
1 - IDLER PULLEY
2 - ACCESSORY DRIVE BELT TENSIONER
3 - MOUNTING BOLT
  1. Remove accessory drive belt. See «REMOVAL»(ref-306154-S30160988302008120900000) .
  2. Remove accessory drive belt tensioner.

Scheme 37

Scheme 37: 2.8L DIESEL
Scheme 37: 2.8L DIESEL
1 - ACCESSORY BELT TENSIONER RETAINING BOLT
2 - POWER STEERING PUMP PULLEY
3 - BELT TENSIONER
4 - BRACKET
5 - POWER STEERING PUMP
6 - POWER STEERING PUMP RETAINING BOLTS
7 - POWER STEERING PUMP PULLEY RETAINING BOLTS

Scheme 38

Scheme 38
Scheme 38
  1. Install belt tensioner on bracket. Tighten retaining bolt to 47 N.m (35 ft. lbs.). 1 - IDLER PULLEY 2 - GENERATOR 3 - IDLER PULLEY 4 - A/C COMPRESSOR 5 - COOLING FAN SUPPORT 6 - VIBRATION DAMPER 7 - BELT TENSIONER 8 - POWER STEERING PUMP 9 - ACCESSORY DRIVE BELT 10 - VISCOUS HEATER
  2. Install accessory drive belt. See «INSTALLATION»(ref-306154-S38527570572008120900000) .
  3. Connect negative battery cable.

3.7L

1 - TIMING CHAIN COVER
2 - BOLT TORQUE TO 41 N.m (30 FT LBS)
3 - AUTOMATIC BELT TENSIONER
  1. Install pulley and pulley bolt to tensioner. Tighten bolt to 61 N.m (45 ft. lbs.) torque.
  2. An indexing slot is located on back of tensioner. Align this slot to the head of the bolt on the front cover. Install the mounting bolt. Tighten bolt to 41 N.m (30 ft. lbs.).
  3. Install drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).
  4. Check belt indexing marks (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).
1 - IDLER PULLEY
2 - ACCESSORY DRIVE BELT TENSIONER
3 - MOUNTING BOLT
  1. Position accessory drive belt tensioner (2).
  2. Install mounting bolt (3). Tighten bolt to Tighten bolt to 61 N.m (45 ft. lbs.).
  3. Install accessory drive belt. See «INSTALLATION»(ref-306154-S38527570572008120900000) .

Scheme 39

Scheme 39: 2.8L DIESEL
Scheme 39: 2.8L DIESEL
CAUTIONThe retaining bolts on the idler pulleys are left hand thread.
  1. Disconnect negative battery cable.
  2. Remove accessory drive belt. See «REMOVAL»(ref-306154-S30160988302008120900000) .
  3. Remove idler pulley retaining bolts and pulley.
1 - IDLER PULLEY
2 - ACCESSORY DRIVE BELT TENSIONER
3 - MOUNTING BOLT
  1. Remove accessory drive belt. See «REMOVAL»(ref-306154-S30160988302008120900000) .
  2. Remove cover.
  3. Remove bolt and pulley (1).
  1. Install idler pulley and retaining bolt. Tighten bolts to 53 N.m (39 ft. lbs.)
  2. Install accessory drive belt. See «INSTALLATION»(ref-306154-S38527570572008120900000) .
  3. Connect negative battery cable.
1 - IDLER PULLEY
2 - ACCESSORY DRIVE BELT TENSIONER
3 - MOUNTING BOLT
  1. Position idler pulley (1).
  2. Tighten bolt to (3) 28 N.m (250 in. lbs.).
  3. Install cover.
  4. Install accessory drive belt. See «INSTALLATION»(ref-306154-S38527570572008120900000) .

ETHYLENE-GLYCOL MIXTURES

CAUTIONRicher antifreeze mixtures cannot be measured with normal field equipment and can cause problems associated with 100 percent ethylene-glycol.

The required ethylene-glycol (antifreeze) and water mixture depends upon the climate and vehicle operating conditions. The recommended mixture of 50/50 ethylene-glycol and water will provide protection against freezing to -37°C (-35°F). The antifreeze concentration must always be a minimum of 44 percent, year-round in all climates. If percentage is lower than 44 percent, engine parts may be eroded by cavitation, and cooling system components may be severely damaged by corrosion. Maximum protection against freezing is provided with a 68 percent antifreeze concentration, which prevents freezing down to -67.7°C (-90°F). A higher percentage will freeze at a warmer temperature. Also, a higher percentage of antifreeze can cause the engine to overheat because the specific heat of antifreeze is lower than that of water.

Use of 100 percent ethylene-glycol will cause formation of additive deposits in the system, as the corrosion inhibitive additives in ethylene-glycol require the presence of water to dissolve. The deposits act as insulation, causing temperatures to rise to as high as 149°C (300°F). This temperature is hot enough to melt plastic and soften solder. The increased temperature can result in engine detonation. In addition, 100 percent ethylene-glycol freezes at 22°C (-8°F).

PROPYLENE-GLYCOL MIXTURES

It's overall effective temperature range is smaller than that of ethylene-glycol. The freeze point of 50/50 propylene-glycol and water is -32°C (-26°F). 5°C higher than ethylene-glycol's freeze point. The boiling point (protection against summer boil-over) of propylene-glycol is 125°C (257°F ) at 96.5 kPa (14 psi), compared to 128°C (263°F) for ethylene-glycol. Use of propylene-glycol can result in boil-over or freeze-up on a cooling system designed for ethylene-glycol. Propylene glycol also has poorer heat transfer characteristics than ethylene glycol. This can increase cylinder head temperatures under certain conditions.

Propylene-glycol/ethylene-glycol mixtures can cause the destabilization of various corrosion inhibitors, causing damage to the various cooling system components. Also, once ethylene-glycol and propylene-glycol based coolants are mixed in the vehicle, conventional methods of determining freeze point will not be accurate. Both the refractive index and specific gravity differ between ethylene glycol and propylene glycol.

GAS ENGINES

WARNINGAntifreeze is an ethylene glycol based coolant and is harmful if swallowed or inhaled. If swallowed, drink two glasses of water and induce vomiting. If inhaled, move to fresh air area. Seek medical attention immediately. Do not store in open or unmarked containers. Wash skin and clothing thoroughly after coming in contact with ethylene glycol. Keep out of reach of children. Dispose of glycol based coolant properly, contact your government agency for location of collection center in your area. Do not open a cooling system when the engine is at operating temperature or hot under pressure, personal injury can result. Avoid radiator cooling fan when engine compartment related service is performed, personal injury can result.
CAUTIONUse of Propylene Glycol based coolants is not recommended, as they provide less freeze protection and less boiling protection.

The cooling system is designed around the coolant. The coolant must accept heat from engine metal, in the cylinder head area near the exhaust valves and engine block. Then coolant carries the heat to the radiator where the tube/fin radiator can transfer the heat to the air.

The use of aluminum cylinder blocks, cylinder heads, and water pumps requires special corrosion protection. Mopar® Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769), or the equivalent ethylene glycol based coolant with hybrid organic corrosion inhibitors (called HOAT, for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% Ethylene Glycol and 50% distilled water to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.

The green coolant MUST NOT BE MIXED with the orange or magenta coolants. When replacing coolant the complete system flush must be performed before using the replacement coolant.

CAUTIONMopar® Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769) may not be mixed with any other type of antifreeze. Doing so will reduce the corrosion protection and may result in premature water pump seal failure. If non-HOAT coolant is introduced into the cooling system in an emergency, it should be replaced with the specified coolant as soon as possible.

DIESEL ENGINE

CAUTIONUse of Propylene Glycol based coolants is not recommended, as they provide less freeze protection and less boiling protection.

The cooling system is designed around the coolant. The coolant must accept heat from engine metal, in the cylinder head area near the exhaust valves and engine block. Then coolant carries the heat to the radiator where the tube/fin radiator can transfer the heat to the air.

The use of aluminum cylinder blocks, cylinder heads, and water pumps requires special corrosion protection. Glysantin G 30-91 Antifreeze/Coolant, 5 Year/150,000 Mile Formula (ASTM D3306), or the equivalent ethylene glycol based coolant. This coolant offers the best engine cooling without corrosion when mixed with 50% coolant and 50% distilled water to obtain a freeze point of -36°C (-34°F). It is dyed purple to distinguish it's unique chemistry from traditional green and yellow silicate coolants. If it loses color or becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.

The purple coolant MUST NOT BE MIXED with the orange, green or magenta coolants. When replacing coolant the complete system flush must be performed before using the replacement coolant.

CAUTIONGlysantin G 30-91 Antifreeze/Coolant, 5 Year/150,00 Mile Formula (ASTM D3306) may not be mixed with any other type of antifreeze. Doing so will reduce the corrosion protection and may result in premature water pump seal failure.

NON-PRESSURE SYSTEM

This system works on the principal of a closed and completely deaerated system using thermally generated pressure. The bottle acts as a reserve coolant source to keep air out of the system but must have a specified minimum amount of coolant in the bottle at all times. The expansion and contraction of the coolant in the pressurized closed coolant loop allows the reserve bottle to accept and give up excess fluid via a hose from the radiator neck. It provides

  1. A non-pressurized reserve coolant tank volume for expansion and contraction of coolant.
  2. A pressurized cap on the radiator. This keeps the main loop of the cooling system at an elevated operating pressure and prevents coolant boiling at lower temperatures.
  3. Reserve coolant is included in the non-pressurized tank in enough quantity to account for minor leaks and evaporation or boiling losses, and to keep the return line back to the radiator full at all times. Failure to do so could allow air to be sucked back into the radiator as the engine and engine coolant cool down and the coolant volume contracts.

PRESSURE SYSTEM

This system works on the principal of a closed and deaerated system using thermally generated pressure. The expansion and contraction of the coolant in the pressurized closed system keeps it free of trapped air. It provides

  1. A pressurized surge tank volume for expansion and contraction.
  2. A non-pressurized overflow volume to capture excess coolant expansion and allow for it's return to the pressurized system.
  3. A pressurized cap on the pressure bottle rather than the radiator. This facilitates deaeration of the system.
  4. Reserve coolant is included in the pressurized volume to account for minor leaks and evaporation or boiling losses.
  5. Provides a warning light for low coolant level.

The coolant reserve/overflow system works in conjunction with the radiator pressure cap. It utilizes thermal expansion and contraction of coolant to keep coolant free of trapped air. It provides a volume for expansion and contraction of coolant. It also provides a convenient and safe method for checking coolant level and adjusting level at atmospheric pressure. This is done without removing the radiator pressure cap. The system also provides some reserve coolant to the radiator to cover minor leaks and evaporation or boiling losses.

As the engine cools, a vacuum is formed in the cooling system of both the radiator and engine. Coolant will then be drawn from the coolant tank and returned to a proper level in the radiator.

As the engine warms, the coolant in the closed system expands. The pressurized bottle accepts the expanding fluid. Then, when the thermostat opens and a high demand for coolant is placed on the system, the pressurized surge tank side of the bottle can supply the temporary additional volume of coolant demanded by the system. Once the water pump catches up with the flow demand, the tank returns to equilibrium. A separate compartment in the bottle accepts the overflow coolant which is then drawn back into the primary side of the bottle when the engine and coolant cool down

The advantage of the pressurized system is that any excess air in the cooling system is routed to the top of the bottle via a vent hose at the thermostat housing to the bottle. This air accumulates at the top of the pressurized volume in the bottle (the highest point in the system) and is forced out of the system through the pressure cap. This keeps the system properly deaerated and maintains pressure in the cooling system to prevent water pump cavitation

The diesel bottle has an additional vent line back to the radiator that is immersed in the coolant bath at the bottle. This also ensures air at the radiator is routed back to bottle for expulsion and that a constant head of liquid is present at the radiator.

Scheme 40

Scheme 40: NON PRESSURE SYSTEM
Scheme 40: NON PRESSURE SYSTEM
1 - RADIATOR PRESSURE CAP
2 - HOSE
3 - COOLANT RECOVERY BOTTLE
  1. Remove hose (2) from radiator.
  2. Remove recovery container mounting bolts.
  3. Remove recovery container (3).

Scheme 41

Scheme 41: PRESSURE SYSTEM
Scheme 41: PRESSURE SYSTEM
1 - PRESSURE CAP
2 - COOLANT BOTTLE
3 - MOUNTING NUTS
4 - COOLANT BOTTLE TO RADIATOR HOSE
5 - CLAMP
6 - RADIATOR
7 - LOWER HOSE
8 - MOUNTING BRACKET
  1. Remove pressure cap from bottle.
  2. Siphon coolant from pressure bottle (2) into a contaminant free container.
  3. Disconnect coolant bottle to radiator hose at coolant bottle.
  4. Disconnect lower hose at coolant bottle.
  5. Remove mounting nuts.
  6. Remove coolant bottle from bracket.
1 - RADIATOR PRESSURE CAP
2 - HOSE
3 - COOLANT RECOVERY BOTTLE
  1. Position coolant recovery container (3).
  2. Install coolant recovery container mounting bolts.
  3. Install hose (2).
1 - PRESSURE CAP
2 - COOLANT BOTTLE
3 - MOUNTING NUTS
4 - COOLANT BOTTLE TO RADIATOR HOSE
5 - CLAMP
6 - RADIATOR
7 - LOWER HOSE
8 - MOUNTING BRACKET
  1. Position pressure bottle on mounting bracket.
  2. Install mounting nuts. Tighten nuts to 8.5 N.m (75 in. lbs.).
  3. Install lower hose at coolant bottle.
  4. Install radiator to coolant bottle hose at coolant bottle.
  5. Fill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .

Scheme 42

Scheme 42: HEATER CORE COOLANT HOSES
Scheme 42: HEATER CORE COOLANT HOSES
  1. Drain cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  2. Remove engine cover from engine. Refer to «REMOVAL»(ref-306142-S07058402912008120900000) . Refer to «REMOVAL»(ref-306143-S20513227792008120900000) .
  3. Disconnect heater core supply line at heater core and viscous heater. Remove hose from vehicle.
  4. Disconnect heater core return line (5) from heater core and EGR cooler. Remove hose from vehicle.

Scheme 43

Scheme 43: UPPER HOSE
Scheme 43: UPPER HOSE
1 - FAN SHROUD
2 - HOSE CLAMP
3 - UPPER RADIATOR HOSE
4 - THERMOSTAT HOUSING
  1. Drain cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  2. Disconnect upper radiator hose (3) from thermostat housing.
  3. Disconnect upper radiator hose from radiator and remove from vehicle.

HEATER CORE COOLANT HOSES

  1. Connect heater core supply hose to heater core and viscous heater. Position hose clamps into proper position.
  2. Connect heater core return hose to heater core and EGR cooler. Position hose clamps into proper position.
  3. Install engine cover to engine. Refer to «INSTALLATION»(ref-306142-S13879575462008120900000) . Refer to «INSTALLATION»(ref-306143-S05654550102008120900000) .
  4. Refill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .

UPPER HOSE

1 - FAN SHROUD
2 - HOSE CLAMP
3 - UPPER RADIATOR HOSE
4 - THERMOSTAT HOUSING
  1. Install upper radiator hose on radiator and thermostat housing.
  2. Reposition hose clamps in proper position.
  3. Refill cooling system to proper level. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
1 - POWER CORD
2 - BLOCK HEATER
3 - CORE HOLE
  1. Thoroughly clean core hole and heater seat.
  2. Insert heater assembly (2) with element loop positioned upward .
  3. With heater seated, tighten center screw securely to assure a positive seal. CAUTION: To prevent damage, the power cord must be secured in its retaining clips, and not positioned so it could contact linkages or exhaust manifold.
  4. Connect power cord to heater.
  5. Lower vehicle.
  6. Fill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
1 - CYLINDER HEAD BOLT
2 - GLOW PLUG
3 - COOLANT FITTING
4 - CYLINDER HEAD ALIGNMENT DOWEL
5 - GLOW PLUG HARNESS
6 - CYLINDER LINER
7 - CYLINDER BLOCK
8 - CYLINDER HEAD GASKET
9 - CYLINDER HEAD
10 - ROCKER ARM ASSEMBLIES
  1. Install coolant temperature sensor in thermostat housing.
  2. Connect coolant temperature sensor electrical connector.
  3. Refill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  4. Connect negative battery cable.
1 - MOUNTING SCREWS
2 - MAP SENSOR
3 - ECT SENSOR
4 - FRONT OF INTAKE MANIFOLD
  1. Apply thread sealant to sensor threads.
  2. Install sensor to engine.
  3. Tighten coolant temperature sensor to 11 N.m (8 ft. lbs.) torque.
  4. Replace any lost engine coolant.

Scheme 44

Scheme 44: DESCRIPTION
Scheme 44: DESCRIPTION
1 - RADIATOR
2 - ELECTRIC COOLING FAN CONNECTOR
3 - FAN SHROUD
4 - 2 SPEED ELECTRIC COOLING FAN

The fan (4) is electrically controlled by the Powertrain Control Module (PCM) through the fan control relays. The relays are located in the PDC in the engine compartment.

VISCOUS RADIATOR FAN

If the fan assembly free-wheels without drag (the fan blades will revolve more than five turns when spun by hand), replace the fan drive. This spin test must be performed when the engine is cool.

For the following test, the cooling system must be in good condition. It also will ensure against excessively high coolant temperature.

WARNINGBe sure that there is adequate fan blade clearance before drilling.
  1. Drill a 3.18-mm (1/8-in) diameter hole in the top center of the fan shroud.
  2. Obtain a dial thermometer with an 8 inch stem (or equivalent). It should have a range of -18° to 105°C (0° to 220°F). Insert thermometer through the hole in the shroud. Be sure that there is adequate clearance from the fan blades.
  3. Connect a tachometer and an engine ignition timing light (timing light is to be used as a strobe light).
  4. Block the air flow through the radiator. Secure a sheet of plastic in front of the radiator (or air conditioner condenser). Use tape at the top to secure the plastic and be sure that the air flow is blocked.
  5. Be sure that the air conditioner (if equipped) is turned off. WARNING: Use extreme caution when the engine is operating. Do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.
  6. Start the engine and operate at 2400 RPM. Within ten minutes the air temperature (indicated on the dial thermometer) should be up to 93°C (200°F). Fan drive engagement should have started to occur at between 91° to 96°C (195° to 205°F). Engagement is distinguishable by a definite increase in fan flow noise (roaring). The timing light also will indicate an increase in the speed of the fan.
  7. When the air temperature reaches 93°C (200°F), remove the plastic sheet. Fan drive disengagement should have started to occur at between 62° to 85°C (145° to 185°F). A definite decrease of fan flow noise (roaring) should be noticed. If not, replace the defective viscous fan drive unit.

Scheme 45

Scheme 45: 2.8L DIESEL
Scheme 45: 2.8L DIESEL
1 - SPECIAL TOOL 6958 SPANNER WRENCH
2 - FAN

Scheme 46

Scheme 46
Scheme 46

Scheme 47

Scheme 47
Scheme 47
  1. Disconnect negative battery cable. NOTE: The thermal viscous fan drive/fan blade assembly is attached (threaded) to fan support.
  2. Remove fan blade/viscous fan drive assembly from water pump using special tool 6958 spanner wrench, by turning mounting nut counterclockwise as viewed from front. Threads on viscous fan drive are RIGHT HAND. 1 - COOLING FAN AND FAN DRIVE VISCOUS CLUTCH ASSEMBLY 2 - FAN SUPPORT
  3. Do not attempt to remove fan/fan drive viscous clutch assembly (1) from vehicle at this time.
  4. Do not unbolt fan blade assembly from fan drive viscous clutch at this time. 1 - IDLER PULLEY 2 - COOLING FAN SUPPORT 3 - RETAINING BOLTS 4 - ENGINE LIFT HOOK
  5. Remove fan shroud to radiator bolts.
  6. Remove fan shroud and fan blade/fan drive viscous clutch assembly as a complete unit from vehicle.
  7. After removing fan blade/fan drive viscous clutch assembly, do not place viscous clutch in horizontal position. If stored horizontally, silicone fluid in the fan drive viscous clutch could drain into its bearing assembly and contaminate lubricant.
  8. Remove four bolts securing fan blade assembly to fan drive viscous clutch.
  9. Remove cooling fan support (2) from engine block.

Scheme 48

Scheme 48: 3.7L/4.0L
Scheme 48: 3.7L/4.0L
  1. Partially drain the cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  2. Remove the upper radiator hose.
  3. Remove the air filter housing assembly. Refer to «REMOVAL»(ref-306142-S04118526142008120900000) . Refer to «REMOVAL»(ref-306143-S30235127132008120900000) .
  4. Using Tool 6958 and adapter pins 8346 (1), remove fan/viscous fan drive assembly from water pump. Do not attempt to remove fan/viscous fan drive assembly from vehicle at this time.
  5. Position the fan/fan drive assembly in the radiator shroud.
  6. Remove the two shroud mounting screws.
  7. Remove the radiator shroud and fan drive assembly.
  8. After removing fan blade/viscous fan drive assembly, do not place viscous fan drive in horizontal position. If stored horizontally, silicone fluid in the viscous fan drive could drain into its bearing assembly and contaminate lubricant.
  9. Remove four bolts securing fan blade assembly to viscous fan drive.

Clean the fan blades using a mild soap and water. Do not use an abrasive to clean the blades.

1 - COOLING FAN AND FAN DRIVE VISCOUS CLUTCH ASSEMBLY
2 - FAN SUPPORT
  1. Assemble fan blade to viscous fan drive. Tighten mounting bolts to 23.7 N.m (210 in. lbs.) torque. NOTE: The viscous fan and fan shroud must be installed as an assembly.
  2. Gently lay fan and viscous drive into fan shroud. 1 - SPECIAL TOOL 6958 SPANNER WRENCH 2 - FAN
  3. Install the fan shroud to radiator mounting bolt. Tighten bolts to 9 N.m (80 in. lbs.) torque.
  4. Thread the fan and viscous drive onto the fan support and tighten nut using special tool 6958 spanner wrench.
  5. Install cooling fan support to engine block. Torque bolts to 149 N.m.(110 ft. lbs.).
  6. Connect negative battery cable.

Scheme 49

Scheme 49: 3.7L/4.0L
Scheme 49: 3.7L/4.0L
  1. Install fan blade assembly to viscous fan drive. Tighten bolts to 23 N.m (17 ft. lbs.) torque.
  2. Position fan blade/viscous fan drive assembly into the radiator shroud.
  3. Install the radiator shroud and fan drive assembly into the vehicle.
  4. Install fan shroud retaining screws. Tighten screws to 6 N.m (50 lbs. in.)
  5. Using Tool 6958, install the fan blade/viscous fan drive assembly to the water pump shaft. Tighten mounting nut to 50 N.m (37 ft. lbs.).
  6. Install the upper radiator hose.
  7. Fill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  8. Connect battery negative cable.

Scheme 50

Scheme 50: 2.8L DIESEL
Scheme 50: 2.8L DIESEL
1 - GASKET
2 - THERMOSTAT HOUSING
3 - BOLT(S)
4 - BRACKET

A pellet-type thermostat controls the operating temperature of the engine by controlling the amount of coolant flow to the radiator.

Scheme 51

Scheme 51: 3.7L/4.0L
Scheme 51: 3.7L/4.0L
1 - FROM HEATER
2 - FROM RADIATOR
3 - TO WATER PUMP
4 - ENGINE BYPASS
5 - THERMOSTAT
CAUTIONDo not operate an engine without a thermostat, except for servicing or testing.

A pellet-type thermostat (5) controls the operating temperature of the engine by controlling the amount of coolant flow to the radiator. On all engines the thermostat is closed below 195°F (90°C). Above this temperature, coolant is allowed to flow to the radiator. This provides quick engine warm up and overall temperature control. On the 3.7L engine the thermostat is designed to block the flow of the coolant bypass journal by 50% instead of completely blocking the flow. This design controls coolant temperature more accurately.

The same thermostat is used for winter and summer seasons. An engine should not be operated without a thermostat, except for servicing or testing. Operating without a thermostat causes other problems. These are: longer engine warm-up time, unreliable warm-up performance, increased exhaust emissions and crankcase condensation. This condensation can result in sludge formation.

  1. Clean old gasket material from cylinder head and thermostat housing.
  2. Install thermostat housing with gasket and support bracket to cylinder head. Torque bolts to 28 N.m (250 in. lbs.).
  3. Connect coolant bypass hose and upper radiator hose to thermostat housing.
  4. Refill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  5. Install engine cover. Refer to «INSTALLATION»(ref-306142-S13879575462008120900000) . Refer to «INSTALLATION»(ref-306143-S05654550102008120900000) .
  6. Connect negative battery cable.
1 - THERMOSTAT HOUSING
2 - THERMOSTAT LOCATION
3 - THERMOSTAT AND GASKET
4 - TIMING CHAIN COVER
  1. Clean mating areas of timing chain cover and thermostat housing.
  2. Install thermostat (spring side down) into recessed machined groove on housing assembly. Make sure rubber seal locating tab is positioned in the corresponding notch in the housing.
  3. Position thermostat housing on timing chain cover.
  4. Install two housing-to-timing chain cover bolts. Tighten bolts to 12 N.m (105 in. lbs.) torque.
  5. Install lower radiator hose on thermostat housing.
  6. Install splash shield.
  7. Lower vehicle.
  8. Fill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  9. Connect negative battery cable to battery.
  10. Start and warm the engine. Check for leaks.
1 - UPPER RADIATOR HOSE
2 - HOSE CLAMP
3 - THERMOSTAT HOUSING MOUNTING BOLT
4 - THERMOSTAT HOUSING
5 - UPPER RADIATOR HOSE TUBE
6 - UPPER RADIATOR HOSE TUBE MOUNTING NUTS
  1. Make sure jiggle pin is at the 12 O'clock position. Position thermostat and thermostat housing lower intake manifold.
  2. Install thermostat housing bolts. Tighten bolts to 35 N.m (25 ft. lbs.).
  3. Install upper radiator hose onto thermostat housing
  4. Position upper radiator hose tube and install mounting nuts. Tighten nuts to 9 N.m, (85 in. lbs.).
  5. Install upper intake manifold. Refer to «INSTALLATION»(ref-306142-S30306992222008120900000) . Refer to «INSTALLATION»(ref-306143-S05495232132008120900000) .
  6. Install air cleaner housing. Refer to «INSTALLATION»(ref-306143-S22322981022008120900000) .
  7. Fill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .

Scheme 52

Scheme 52: DESCRIPTION
Scheme 52: DESCRIPTION
1 - RADIATOR

All vehicles are equipped with a cross flow type radiator (1) with plastic side tanks.

Plastic tanks, while stronger than brass, are subject to damage by impact, such as from tools or wrenches. Handle radiator with care.

Scheme 53

Scheme 53: REMOVAL
Scheme 53: REMOVAL
1 - AIR DAM
2 - RADIATOR
3 - AIR DAM
4 - A/C CONDENSER
5 - AIR SEAL
WARNINGDo not remove the cylinder block drain plugs or loosen the radiator draincock with the system hot and under pressure. Serious burns from coolant can occur. Refer to cooling system draining.

Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

CAUTIONWhen removing the radiator or A/C condenser for any reason, note the location of all radiator-to-body and radiator-to-A/C condenser rubber air seals. These are used at the top, bottom and sides of the radiator and A/C condenser. To prevent overheating, these seals must be installed to their original positions.

Scheme 54

Scheme 54
Scheme 54
  1. Disconnect the negative battery cable at battery.
  2. Drain coolant from radiator. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  3. Remove the front grille. Refer to «REMOVAL»(ref-306147-S37207605592008120900000) .
  4. Remove the cooling fan from the engine, if equipped.
  5. Remove the two radiator mounting bolts.
  6. Disconnect the connector for the electric fan.
  7. Disconnect the power steering cooler line from cooler.
  8. Disconnect the radiator upper and lower hoses.
  9. Disconnect the overflow hose from radiator (2). 1 - RADIATOR 2 - ALIGNMENT DOWEL 3 - RADIATOR LOWER ISOLATOR 4 - RADIATOR LOWER CROSSMEMBER
  10. The lower part of radiator is equipped with two alignment dowel pins (2). They are located on the bottom of radiator tank and fit into rubber grommets. These rubber grommets are pressed into the radiator lower crossmember. WARNING: The air conditioning system (if equipped) is under a constant pressure even with the engine off. Refer to refrigerant warnings in, heating and air conditioning before handling any air conditioning component. NOTE: The radiator and radiator cooling fan can be removed as an assembly. It is not necessary to remove the cooling fan before removing or installing the radiator.
  11. Gently lift up and remove radiator from vehicle. Be careful not to scrape the radiator fins against any other component. Also be careful not to disturb the air conditioning condenser (if equipped).

Clean radiator fins With the engine cold, apply cold water and compressed air to the back (engine side) of the radiator to flush the radiator and/or A/C condenser of debris.

Clean the radiator pressure cap using a mild soap and water only.

1 - FROM HEATER
2 - FROM RADIATOR
3 - TO WATER PUMP
4 - ENGINE BYPASS
5 - THERMOSTAT

The 3.7L engine uses an internal water/coolant bypass system. The design uses galleries in the timing chain cover to circulate coolant during engine warm-up preventing the coolant from flowing through the radiator. The thermostat uses a stub shaft located at the rear of the thermostat to control flow through the bypass gallery.

Scheme 55

Scheme 55: 4.0L
Scheme 55: 4.0L
1 - INTEGRAL WATER PUMP PULLEY
2 - TIMING CHAIN COVER
3 - THERMOSTAT HOUSING
4 - HEATER HOSE FITTINGS
5 - WATER PUMP

A centrifugal water pump (5) circulates coolant through the water jackets, passages, intake manifold, radiator core, cooling system hoses and heater core. The pump is driven from the engine crankshaft by a single serpentine drive belt.

The water pump impeller is pressed onto the rear of a shaft that rotates in bearings pressed into the housing. The housing has two small holes to allow seepage to escape. The water pump seals are lubricated by the antifreeze in the coolant mixture. No additional lubrication is necessary.

Both heater hoses are connected to fittings on the timing chain front cover. The water pump is also mounted directly to the timing chain cover and is equipped with an integral pulley.

The water pump is used to circulate coolant through the cooling system. The coolant is pumped through the engine block, cylinder head, heater core, EGR cooler, viscous heater, and radiator.

A centrifugal water pump circulates coolant through the water jackets, passages, intake manifold, radiator core, cooling system hoses and heater core, this coolant absorbs the heat generated when the engine is running. The pump is driven by the engine crankshaft via a drive belt.

Scheme 56

Scheme 56: 2.8L DIESEL
Scheme 56: 2.8L DIESEL

Scheme 57

Scheme 57
Scheme 57

Scheme 58

Scheme 58
Scheme 58

Scheme 59

Scheme 59
Scheme 59

Scheme 60

Scheme 60
Scheme 60
  1. Remove the radiator fan. See «REMOVAL»(ref-306154-S21887878352008120900000) .
  2. Disconnect negative battery cable.
  3. Drain cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  4. Remove the upper front cover.
  5. Remove the crankshaft damper and lower front cover.
  6. Remove the timing belt.
  7. Remove the inner front cover.
  8. Remove water pump retaining bolts and pump.
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER PINS 8346
2 - FAN

Scheme 61

Scheme 61
Scheme 61
  1. Disconnect negative battery cable.
  2. Drain cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  3. If water pump is being replaced, do not unbolt fan blade assembly from thermal viscous fan drive.
  4. Remove two fan shroud-to-radiator screws. Disconnect the coolant overflow hose.
  5. Remove upper fan shroud and fan blade/viscous fan drive assembly from vehicle.
  6. After removing fan blade/viscous fan drive assembly, do not place thermal viscous fan drive in horizontal position. If stored horizontally, silicone fluid in viscous fan drive could drain into its bearing assembly and contaminate lubricant. 1 - AUTOMATIC TENSIONER 2 - WATER PUMP PULLEY
  7. Remove accessory drive belt (1). See «REMOVAL»(ref-306154-S30160988302008120900000) .
  8. Remove lower radiator hose clamp and remove lower hose at water pump.
  9. Remove seven water pump mounting bolts and one stud bolt. CAUTION: Do not pry water pump at timing chain case/cover. The machined surfaces may be damaged resulting in leaks.
  10. Remove water pump and gasket. Discard gasket.

Scheme 62

Scheme 62: 4.0L
Scheme 62: 4.0L

Scheme 63

Scheme 63
Scheme 63
  1. Disconnect negative battery cable.
  2. Remove air filter housing. Refer to «REMOVAL»(ref-306143-S23132016952008120900000) .
  3. Drain cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  4. Remove coolant recover container. See «REMOVAL»(ref-306154-S39360093762008120900000) .
  5. Remove viscous radiator fan. See «REMOVAL»(ref-306154-S21887878352008120900000) .
  6. Remove RH engine mount through bolt.
  7. Raise engine assembly.
  8. Remove front A/C compressor front mounting nuts and studs
  9. Remove accessory drive belt bracket.
  10. Remove engine timing belt. Refer to «REMOVAL»(ref-306142-S28673550012008120900000) . Refer to «REMOVAL»(ref-306143-S05505308212008120900000) . 1 - M8 FASTENERS (APPLY THREAD SEALANT) 2 - M10 FASTENERS 3 - M6 FASTENERS 4 - M10 FASTENERS (STUD/NUT)
  11. Remove water pump mounting bolts (3).
  12. Remove water pump.
  13. Clean mounting surface.

Clean the gasket mating surface. Use caution not to damage the gasket sealing surface.

1 - M8 FASTENERS (APPLY THREAD SEALANT)
2 - M10 FASTENERS
3 - M6 FASTENERS
4 - M10 FASTENERS (STUD/NUT)
  1. Position water pump and new gasket.
  2. Install water pump mounting bolts. Tighten to 54 N.m (40 ft. lbs.).
  3. Install engine timing belt. Refer to «INSTALLATION»(ref-306142-S24119590672008120900000) . Refer to «INSTALLATION»(ref-306143-S40647239562008120900000) .
  4. Install accessory drive bracket. Tighten bolts to Tighten to 54 N.m (40 ft. lbs.). 1 - Item_1 2 - Item _2
  5. Install front A/C compressor mounting studs. and nuts. Tighten studs to
  6. Install A/C compressor mounting nuts. Tighten nuts to 28 N.m (21 ft. lbs.).
  7. Lower engine and install RH engine mount through bolt. Tighten bolt to 54 N.m (40 lbs. ft.).
  8. Install accessory drive belt. See «INSTALLATION»(ref-306154-S38527570572008120900000) .
  9. Install viscous radiator fan. See «INSTALLATION»(ref-306154-S41209272742008120900000) .
  10. Install coolant recover container. See «INSTALLATION»(ref-306154-S03099954612008120900000) .
  11. Install air filter assembly. Refer to «INSTALLATION»(ref-306143-S22322981022008120900000) .
  12. Connect negative battery cable.
  13. Fill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  1. Clean mating surfaces of water pump housing and engine block as necessary.
  2. Place new O-ring in groove in water pump housing. Install water pump and retaining bolts. Torque bolts to 24 N.m (212 in. lbs.).
  3. Install the water pump torque the water pump bolts to 32 Nm (23 ft. lbs.) Install the inner front cover. Install the timing belt. Install the outer front cover (2).
  4. Install the crankshaft damper (1).
  5. Install the upper front cover.
  6. Install the lifting bracket.
  7. Install the fan. See «INSTALLATION»(ref-306154-S41209272742008120900000) .
  8. Refill cooling system. See «STANDARD PROCEDURE»(ref-306154-S25259837052008120900000) .
  9. Connect negative battery cable.

Scheme 64

Scheme 64: DISCONNECT
Scheme 64: DISCONNECT
1 - QUICK CONNECT FITTING
2 - DUST CAP
3 - OIL COOLER LINE
4 - SPECIAL TOOL 8875A
  1. Remove dust cap by pulling it straight back off of quick connect fitting (1).
  2. Place properly sized Release Tool (4) onto transmission cooler line with the fingers of the tool facing the quick connect fitting.
  3. Slide Release Tool down the transmission line and engage the fingers of the tool into the retaining clip. When properly engaged in the clip, the tool will fit flush against the quick connect fitting.
  4. Rotate the release tool 60° to expand the retaining clip.
  5. While holding the release tool against the quick connect fitting, pull back on the transmission cooler line to remove.
  6. If quick connect fitting is damaged or leaking at transmission oil cooler or transmission, remove fitting.

Scheme 65

Scheme 65: CONNECT
Scheme 65: CONNECT
1 - QUICK CONNECT FITTING
2 - CLIP
3 - OIL COOLER LINE
4 - DUST CAP
  1. If removed, install quick connect fitting into transmission oil cooler or transmission. Tighten fitting to 15 N.m (132 in. lbs.).
  2. Align transmission cooler line (3) with quick connect fitting while pushing straight into the fitting.
  3. Push in on transmission cooler line until a "click" is heard or felt.
  4. Slide dust cap (4) down the transmission cooler line and snap it over the quick connect fitting until it is fully seated and rotates freely. Dust cap will only snap over quick connect fitting when the transmission cooler line is properly installed.

Note. If dust cap will not snap into place, repeat assembly step #2.

More articles — Engine Cooling System