Cooling System — part 2 of 2 — 1998 Jeep Grand Cherokee ZJ Export Service Manual
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Pages 287–299 · 13 pages · 13 words repaired
certain drive line components. repair as necessary.
One or more of these shields
may be missing.
2. Is temperature gauge reading 2. Refer to the previous Temperature
above the normal range? Gauge Reads High in these Diagnosis
Charts. Repair as necessary.
3. Is cooling fan operating 3. Refer to Cooling System Fan in this
correctly? group for diagnosis. Repair as necessary.
4. Has undercoating been applied 4. Clean undercoating as necessary.
to any unnecessary component?
STEAM IS COMING FROM 1. During wet weather, moisture 1. Occasional steam emitting from this area
FRONT OF VEHICLE NEAR (snow, ice or rain condensation) is normal. No repair is necessary.
GRILL AREA WHEN on the radiator will evaporate
WEATHER IS WET, when the thermostat opens.
ENGINE IS WARMED UP This opening allows heated
AND RUNNING, AND water into the radiator. When
VEHICLE IS STATIONARY. the moisture contacts the hot
TEMPERATURE GAUGE IS radiator, steam may be emitted.
IN NORMAL RANGE This usually occurs in cold
weather with no fan or airflow to
blow it away.
COOLANT COLOR 1. Coolant color is not necessarily | 1. Refer to Coolant in this group for
an indication of adequate antifreeze tests. Adjust antifreeze-to-
corrosion or temperature water ratio as necessary.
protection. Do not rely on
coolant color for determining
condition of coolant.
COOLANT LEVEL 1. Level changes are to be 1. A normal condition. No repair is
CHANGES IN COOLANT expected as coolant volume necessary.
TANK. TEMPERATURE fluctuates with engine
GAUGE IS IN NORMAL temperature. If the level in the
RANGE tank was between the HOT and
COLD marks at normal engine
operating temperature, the level
should return to within that
range after operation at elevated
temperatures.
J9507-74
TESTING COOLING SYSTEM FOR LEAKS
ULTRAVIOLET LIGHT METHOD
All Jeepy models have a leak detection additive added to the cooling system before they leave the factory. The additive is highly visible under ultraviolet light (black light). If the factory original coolant has been drained, pour one ounce of additive into the cooling system. The additive is available through the parts department. Place the heater control unit in HEAT position. Start and operate the engine until the radiator upper hose is warm to the touch. Aim the commercially available black light tool at the components to be checked. If leaks are present, the black light will cause the additive to glow a bright green color.
The black light can be used along with a radiator pressure tester to determine if any external leaks exist (Fig. 8).
PRESSURE TESTER METHOD
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE SERIOUS INJURY BY SCALDING. NEVER REMOVE THE PRESSURE/VENT CAP OR PRES- SURE TESTER WHEN THE COOLING SYSTEM IS HOT OR UNDER PRESSURE!
Allow the engine to cool sufficiently so that the system is not under pressure and carefully remove the pressure/vent cap from the filler neck. Warm the engine with the pressure/vent cap off to normal operating temperature. With the engine turned off attach the cooling system pressure tester and test the system as described below.
Recheck the system cold if the cause of coolant loss is not located during warm engine examination.
Operate the tester pump to apply 103 kPa (15 psi) pressure to the system. If the hoses enlarge excessively or bulge while testing, replace as necessary. Observe the gauge pointer and determine the condition of the cooling system according to the following criteria:
• Holds Steady: If the pointer remains steady for two minutes, there are no serious coolant leaks in the system. However, there could be an internal leak that does not appear with normal system test pressure. Inspect for interior leakage or do the Internal Leakage Test. Do this if it is certain that coolant is being lost and no leaks can be detected.
• Drops Slowly: Shows a small leak or seepage is occurring. Examine all connections for seepage or slight leakage with a flashlight. Inspect the radiator, hoses, gasket edges and heater. Seal any small leak holes with a Sealer Lubricant or equivalent. Repair leak holes and reinspect the system with pressure applied.
• Drops Quickly: Shows that a serious leakage is occurring. Examine the system for serious external leakage. If no leaks are visible, inspect for internal leakage. Large radiator leak holes should be repaired by a reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove the oil pan drain plug and drain a small amount of engine oil. Coolant, being heavier will drain first, or operate engine to churn oil, then examine dipstick for water globules. Operate the engine without the pressure/vent cap on the coolant tank until thermostat opens.
Attach a radiator pressure tester to the tank filler neck. If pressure builds up quickly, a leak exists as result of a faulty cylinder head gasket or crack in the engine. Repair as necessary.
WARNING: DO NOT ALLOW PRESSURE TO EXCEED 117 KPA (17 PSI). TURN THE ENGINE OFF. TO RELEASE THE PRESSURE, ROCK THE TESTER FROM SIDE TO SIDE. WHEN REMOVING THE TESTER, DO NOT TURN THE TESTER MORE THAN 1/2 TURN IF THE SYSTEM IS UNDER PRESSURE.
If there is no immediate pressure increase, pump the pressure tester until the indicated pressure is within the system range. Vibration of the gauge pointer indicates compression or combustion leakage into the cooling system.
LOW COOLANT LEVEL- AERATION
CAUTION: Engine damage could occur if the coolant level is allowed to get this low. Always ensure that the coolant level is not below the add coolant mark. The baffles in the pressurized coolant tank (degasser bottle) will not allow you to see the fluid level. Check the coolant level through the pressurized coolant tank. For better visibility of the coolant level use a shop lamp to light the pressurized coolant tank and look through the pressurized coolant tank.
If the coolant level in the radiator drops below the top of radiator core tubes, air will enter the cooling system.
Low coolant level can cause the thermostat pellet to be suspended in air instead of coolant. This will cause the thermostat to open later, which in turn causes higher coolant temperature. Air trapped in the cooling system also reduces the amount of coolant circulating in the heater core resulting in low heat output.
BELT DIAGNOSIS
When diagnosing serpentine accessory drive belts, small cracks that run across the ribbed surface of the belt from rib to rib (Fig. 10), are considered normal. These are not a reason to replace the belt. However, cracks running along a rib (not across) are not nor mal. Any belt with cracks running along a rib must be replaced (Fig. 10). Also replace the belt if it has excessive wear, frayed cords or severe glazing.
Refer to the Serpentine Drive Belt Diagnosis chart for further belt diagnosis.
SERVICE PROCEDURES
COOLANT LEVEL CHECK
The coolant level is checked and adjusted at the pressurized coolant tank. The tank is located at the right-rear side of the engine compartment and is mounted as the highest point of the cooling system. This will allow any air or vapor exceeding the pressure/vent cap rating to escape through the cap. The coolant tank is equipped with a cam type pressure/ vent cap. Refer to Pressure/Vent Cap for additional information. A coolant reserve/overflow system with a separate tank is not used with the 2.5L diesel engine.
(1) Add coolant into the coolant tank up to the COLD mark. If possible, only add coolant when the engine is cold. Coolant level in a warm engine will be higher in the tank due to thermal expansion.
(2) After the engine has been operated through a few heat-up and cool-down cycles, recheck the coolant level in the tank.
DRAINING COOLING SYSTEM
The cooling system is equipped with a pressurized coolant tank using a pressure/vent cap.
RIB CHUNKING (ONE 1. Foreign objects imbedded in 1. Remove foreign objects from pulley
OR MORE RIBS HAS pulley grooves. grooves. Replace belt.
SEPARATED FROM 2 A |
BELT Body . Installation damage. 2. Replace belt.
RIB OR BELT WEAR 1. Pulley(s) misaligned. 1. Align pulley(s).
2. Abrasive environment. 2. Clean pulley(s). Replace belt if necessary.
3. Rusted pulley(s). 3. Clean rust from pulley(s).
4. Sharp or jagged pulley 4. Replace pulley.
groove tips.
5. Rubber deteriorated. 5. Replace belt.
LONGITUDINAL BELT 1. Belt has mistracked from 1. Replace belt.
CRACKING (CRACKS pulley groove.
BETWEEN TWO RIBS) | 2. Pulley groove tip has worn 2. Replace belt.
away rubber to tensile
member.
BELT SLIPS 1. Belt slipping because of 1. Replace automatic belt tensioner.
insufficient tension.
2. Incorrect belt. 2. Replace belt.
3. Belt or pulley subjected to 3. Replace belt and clean pulleys.
substance (belt dressing, oil,
ethylene glycol) that has
reduced friction.
4. Driven component bearing 4. Replace faulty component bearing.
failure.
5. Belt glazed and hardened 5. Replace belt.
from heat and excessive
slippage.
“GROOVE JUMPING” 1. Belt tension either too high or 1. Replace automatic belt tensioner.
(BELT DOES NOT too low.
ON 2. Incorrect belt. 2. Replace belt.
) 3. Pulley(s) not within design 3. Replace pulley(s).
tolerance.
4. Foreign object(s) in grooves. 4. Remove foreign objects from grooves.
4. Pulley misalignment. 4. Check and replace.
5. Belt cordline is broken. 5. Replace belt.
BELT BROKEN 1. Excessive tension. 1. Replace belt and automatic belt tensioner.
(NOTE: IDENTIFY AND 2. Incorrect belt. 2. Replace belt.
CORRECT PROBLEM 3. Tensil ber d d 3. Repl belt
BEFORE NEW BELT durin bolt i ‘all amage , MEeplace Delt.
IS INSTALLED) uring belt installation.
4. Severe misalignment. 4, Check and replace.
5. Bracket, pulley, or bearing 5. Replace defective component and belt.
failure.
NOISE (OBJECTIONAL 1. Belt slippage. 1. Replace belt or automatic belt tensioner.
SQUEAL, SQUEAK, OR 2. Bearing noise. 2. Locate and repair.
RUMBLE IS HEARD OR 3. Belt misali 3. Repl belt
FELT WHILE DRIVE . Belt misalignment. . Replace belt.
BELT IS INOPERATION)| Belt-to-pulley mismatch. 4. Install correct belt.
ee J9507-27
WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN-PLUG, THE COOLANT TANK CAP, THE RADIATOR FILL VENT VALVE, OR LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.
WARNING: IF VEHICLE HAS BEEN RUN RECENTLY, WAIT AT LEAST 15 MINUTES BEFORE REMOVING COOLANT TANK CAP. WITH A RAG, SQUEEZE THE UPPER RADIATOR HOSE TO CHECK IF SYSTEM IS UNDER PRESSURE. PLACE A RAG OVER THE CAP. VERY SLOWLY ROTATE THE CAP COUNTERCLOCKWISE ALLOWING PRESSURE TO SLOWLY RELEASE. AFTER ALL PRESSURE HAS BEEN RELEASED, REMOVE THE COOLANT TANK CAP COMPLETELY.
DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
(1) Observe the previous WARNINGS and remove the coolant tank pressure/vent cap.
(2) The plastic radiator draincock is located on the bottom of the left radiator tank. It can be accessed from the bottom of vehicle.
(a) Attach one end of a 24 inch long X 1/4 inch ID drain-hose to the nipple below the radiator draincock.
(b) Put the other end of drain-hose into a clean container.
(c) Open the draincock (counterclockwise as viewed from left side of vehicle) and drain coolant from radiator. (3)
If the complete cooling system must be drained,
(Fig. 11). This hex. headed plug is located on the right/rear side of the engine above the starter motor.
REFILLING COOLING SYSTEM
The cooling system is equipped with a pressurized coolant tank using a pressure/vent cap. Refilling of the system is done through this tank.
NOTE: The radiator draincock is equipped with a rubber o-ring. Do not over tighten draincock.
(1) Tighten the radiator draincock and (if removed), the cylinder block drain-plug.
(2) Remove the plastic radiator fill vent valve (unscrews counter- clockwise) from the radiator. The fill vent valve is located on the top of the right radiator tank (Fig. 12).
(3)
With the fill vent valve removed, proceed to fill the system using a 50/50 mixture of water and antifreeze as described in the Coolant section of this group.
(4)
Continue to fill the cooling system until coolant is observed escaping from the fill vent opening. When this valve Js equipped with a rubber © ring. Do not over tighten the fill vent valve.
(5) Continue to fill the system until the coolant tank is full.
(6) Install and tighten the coolant tank pressure/ vent cap. Do not use any type of tool when tightening the cap. Hand tighten only.
(7) With the heater control unit in the HEAT position, operate engine with coolant tank cap tightened.
(8) After engine has reached normal operating temperature, shut engine off and allow it to cool.
(9) Remove coolant tank cap. (10) Add coolant into the coolant tank up to the COLD mark. If possible, only add coolant when the engine is cold. Coolant level in a warm engine will be higher in the tank due to thermal expansion.
(11) After the engine has been operated through a few heat-up and cool-down cycles, recheck the coolant level in the tank.
COOLANT REPLACEMENT
It is recommended that the cooling system be drained and flushed at 84,000 kilometers (52,500 miles), or 3 years, whichever occurs first. Then every two years, or 48,000 kilometers (30,000 miles), whichever occurs first.
REMOVAL AND INSTALLATION
RADIATOR
WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN-PLUG, THE COOLANT TANK CAP, THE RADIATOR FILL VENT VALVE, OR LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
WARNING: CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES. WHEN REMOVING OR INSTALLING, USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP (Fig. 13). ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the tongue of constant tension clamps (Fig. 14). If replacement is necessary, use only an original equipment clamp with matching number or letter.
REMOVAL
(1) Disconnect negative battery cable at battery. (2) Observe the previous WARNINGS. (3) Drain cooling system. Refer to Draining Cooling System in this group. (4) Remove the upper fan shroud-to-upper crossmember mounting bolts. One of the bolts is mounted vertically at the bottom of the fan shroud.
(5) Lift the fan shroud up until alignment tabs at the bottom are clear of slots in bracket at bottom of radiator. Slip the fan shroud rearward and position it over the fan blades.
(6) Remove radiator hose clamps and remove radiator hoses.
(7) Mark the position of the hood latch striker on the radiator crossmember and remove hood latch striker.
(8) Remove radiator upper crossmember. (9) If equipped with air conditioning, separate the radiator from the A/C condenser by removing the condenser-to-radiator mounting brackets.
(10) Lift radiator straight up and out of engine compartment taking care not to damage radiator or A/C condenser fins.
INSTALLATION
The radiator is equipped with two alignment dowels (Fig. 15). They are located on the bottom of the plastic side tanks and fit into rubber grommets located in the front lower crossmember.
(1) Carefully lower the radiator into engine compartment. Position the alignment dowels on the bottom of radiator into the rubber grommets in front lower crossmember (Fig. 15).
(2) If equipped with air conditioning, attach condenser to radiator with mounting brackets.
(3) Install radiator upper crossmember. (4) Install hood latch striker. (5) Connect radiator upper and lower hoses. (6) Insert alignment tabs at bottom of fan shroud into slots in bracket at bottom of radiator. Install and tighten fan shroud bolts to 3 N·m (31 in. lbs.) torque.
(7) Connect negative battery cable. (8) Fill cooling system with correct coolant. Refer to Refilling Cooling System in this group.
(9) Start and warm the engine. Check for coolant leaks.
FAN BLADE REMOVAL
FAN BLADE REMOVAL
Accessory drive belt removal is not necessary for fan blade or viscous fan drive removal.
(1) Disconnect negative battery cable from battery. (2)
The thermal viscous fan drive/fan blade assembly is attached (threaded) to the fan pulley shaft (Fig. 16). Remove fan blade/viscous fan drive assembly from fan pulley by turning mounting nut counter-clockwise as viewed from front. Threads on viscous fan drive are
Snap-Ont 36 MM Fan Wrenches (number SP346) can be used to turn the mounting nut and to hold the fan pulley from rotating.
RIGHT HAND.
(3) Do not attempt to remove fan/viscous fan drive assembly from vehicle at this time.
(4) Do not unbolt fan blade assembly from viscous fan drive at this time.
Assembly
(5) Remove the fan shroud mounting bolts. One of the bolts is mounted vertically at the bottom of shroud.
(6) Remove fan shroud and fan blade/viscous fan drive assembly as a complete unit from vehicle.
(7) 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.
CAUTION: Do not attempt to remove the fan pulley bolts. The fan pulley is under tension from the drive belt.
(8) Remove four bolts securing fan blade assembly to viscous fan drive (Fig. 16).
FAN BLADE INSTALLATION
(1) Install fan blade assembly to viscous fan drive. Tighten bolts (Fig. 16) to 23 N·m (200 in. lbs.) torque.
(2) Position fan shroud and fan blade/viscous fan drive assembly to vehicle as a complete unit.
(3) Install and tighten fan shroud bolts to 3 N·m (31 in. lbs.) torque.
(4) Install fan blade/viscous fan drive assembly to fan pulley shaft (Fig. 16).
(5) Connect negative battery cable.
VISCOUS FAN DRIVE
The thermal viscous fan drive (Fig. 17) is a silicone-fluid-filled coupling. It connects the fan blade assembly to the fan pulley. The coupling allows the fan to be driven in a normal manner. This is done at low engine speeds while limiting the top speed of the fan to a predetermined maximum level at higher engine speeds. A bimetallic spring coil is located on the front face. This spring coil reacts to the temperature of the radiator discharge air. It engages the viscous fan drive for higher fan speed if the air temperature from the radiator rises above a certain point. Until additional engine cooling is necessary, the fan will remain at a reduced rpm regardless of engine speed.
The viscous fan drive will only engage when sufficient heat is present. This is when the air flowing through the radiator core causes a reaction from the bimetallic coil. It then increases fan speed to provide the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge temperature will drop. The bimetallic coil again reacts and the fan speed is reduced to the previous disengaged speed.
CAUTION: Some engines equipped with serpentine drive belts have reverse rotating fans and viscous fan drives. They are marked with the word REVERSE to designate their usage. Installation of the wrong fan or viscous fan drive can result in engine overheating.
NOISE
NOTE: It is normal for fan noise to be louder (roaring) when:
• The underhood temperature is above the engagement point for the viscous drive coupling. This may occur when ambient (outside air temperature) is very high.
• Engine loads and temperatures are high such as when towing a trailer.
• Cool silicone fluid within the fan drive unit is being redistributed back to its normal disengaged (warm) position. This can occur during the first 15 seconds to one minute after engine start-up on a cold engine.
LEAKS
Viscous fan drive operation is not affected by small oil stains near the drive bearing. If leakage appears excessive, replace the fan drive unit.
THERMOSTAT
REMOVAL
WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN-PLUG, THE COOLANT TANK CAP, THE RADIATOR FILL VENT VALVE, OR LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.
DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
(1) Drain the coolant from the radiator until the level is below the thermostat housing. Refer to Draining Cooling System for procedures.
WARNING: CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES. WHEN REMOVING OR INSTALLING, USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP (Fig. 13). ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the tongue of constant tension clamps (Fig. 14). If replacement is necessary, use only an original equipment clamp with matching number or letter.
(2) Remove the upper radiator hose at the thermostat housing.
Remove the four thermostat housing bolts (Fig. 18)
(3)
(4) Remove the thermostat housing from the water manifold.
(5) Remove the thermostat and rubber seal from the water manifold.
(6)
Thoroughly clean the rubber seal mating surfaces.
INSTALLATION
(1) Install a new rubber seal around the outer lip of the thermostat (a notch is provided in the rubber seal). Do not apply any adhesive to this seal.
(2) Install the replacement thermostat and rubber seal as one assembly into the water manifold adapter (the pointed end of the thermostat should be facing towards the front of engine (Fig. 18). Observe the recess groove in the water manifold adapter. Be sure the thermostat vent is in the 12 o'clock position (Fig. 18).
(3) Position the thermostat housing and four bolts to the water manifold.
CAUTION: Tightening the thermostat housing unevenly or with the thermostat out of its recess groove, may result in a cracked housing.
(4) Tighten the four housing bolts to 11 N·m (98 in. lbs.) torque. (5) Install radiator hose to thermostat housing.
(6) Be sure that the radiator drain is tightly closed. Fill the cooling system to the correct level with the required coolant mixture. Refer to Refilling Cooling System in this group for procedures.
(7) Start and warm the engine. Check thermostat and hose for leaks.
DRIVE BELT
CAUTION: The drive belt on the 2.5L diesel engine is equipped with a spring loaded automatic belt tensioner. After belt installation, do not attempt to check belt tension with a belt tension gauge.
AUTOMATIC BELT TENSIONER
WATER PUMP
REMOVAL
The water pump can be removed without discharging the air conditioning system (if equipped).
The water pump is serviced by replacing the pump and its impeller only. The water pump adapter (Fig. 20) does not have to be removed. The pump impeller is pressed on the rear of the pump shaft and bearing assembly. The pump is serviced only as a complete assembly with the impeller, housing, hub and bearing.
A rubber o-ring seal (instead of a gasket) is used as a seal between the water pump and the water pump adapter.
TYPICAL
WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN-PLUG, THE COOLANT TANK CAP, THE RADIATOR FILL VENT VALVE, OR LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.
DO NOT WASTE reusable coolant. If the solution is clean, drain coolant into a clean container for reuse.
(1) Disconnect negative battery cable at battery. (2) Drain the cooling system. Refer to Draining Cooling System in this group.
(3) The thermal viscous fan drive and the fan blade assembly are attached (threaded) to the fan pulley shaft (Fig. 21). Remove the fan/fan drive assembly from the fan pulley by turning the mounting nut counterclockwise (as viewed from front). Threads on the fan drive are RIGHT HAND. Snap- Ont 36 MM Fan Wrenches (number SP346) can be used to turn the mounting nut and to hold the fan pulley from rotating.
(4) If the water pump is being replaced, do not unbolt the fan blade assembly (Fig. 21) from the thermal viscous fan drive.
Assembly
(5) Remove the upper fan shroud-to-upper crossmember mounting bolts. One of the bolts is mounted vertically at the bottom of the fan shroud.
(6) Slip the fan shroud rearward. Remove the fan shroud and viscous drive/fan blade together as one assembly from the engine compartment.
(7) Loosen but do not remove the 3 water pump pulley bolts (Fig. 20).
(8) Remove the drive belt by removing the automatic belt tensioner. For procedures, refer to Belt Removal/Installation in the Engine Accessory Drive Belts section of this group.
WARNING: CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES. WHEN REMOVING OR INSTALLING, USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP (Fig. 22). ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the tongue of constant tension clamps (Fig. 23). If replacement is necessary, use only an original equipment clamp with matching number or letter.
(9) A metal coolant tube (used to connect rubber coolant hoses), and its mounting bracket are attached to the front of the water pump (Fig. 24). A rubber hose connects this tube to the engine. Disconnect the hose clamp and rubber hose at the back of the thermostat. Position the hose to the side.
(10) Remove the 3 water pump pulley bolts (Fig. 20).
(11) Remove the water pump pulley from the water pump.
(12) Disconnect the drain hose from the vent tube at the bottom of water pump (Fig. 20).
(13) Remove the 4 water pump mounting bolts (Fig. 20).
(14) Remove water pump from engine.
INSTALLATION
(1) Clean the o-ring mating surfaces. If the original pump is to be reinstalled, remove any deposits or other foreign material. Inspect the water pump, water pump adapter and water pump mating surfaces for erosion or damage from cavitation.
(2) Position a new rubber o-ring seal (Fig. 20) between the pump and pump adapter. Hold the seal with petroleum jelly.
(3) Position the pump to the engine. (4) Position the metal coolant tube and its mounting bracket to the pump. (5) Install the four water pump mounting bolts. Tighten bolts to 24 N·m (18 ft. lbs.) torque.
(6) Install drain hose to vent tube at bottom of pump.
(7) Position the water pump pulley to the water pump.
(8)
Install the water pump pulley bolts finger tight.
(9) Install the rubber coolant hose near the thermostat.
(10) Install the drive belt and belt tensioner. For procedures, refer to Belt Removal/Installation in the Engine Accessory Drive Belts section of this group.
(11) Tighten the water pump pulley bolts to 24 N·m (18 ft. lbs.) torque.
(12) Position the viscous drive/fan blade and fan shroud to the engine compartment as one assembly.
(13) Install the thermal viscous fan drive and fan blade to fan pulley. Tighten to 56 N·m (41 ft. lbs.) torque.
(14) Install and tighten fan shroud mounting bolts to 3 N·m (31 in. lbs.) torque.
(15)
Fill cooling system with coolant and check for leaks. Refer to Refilling Cooling System in this group.
(16) Connect battery cable to battery. (17) Start and warm the engine. Check for leaks.
CLEANING AND INSPECTION
WATER PUMP
INSPECTION
Replace the water pump assembly if it has any of the following conditions:
• The body is cracked or damaged • Water leaks from the shaft seal. This is evident by traces of coolant below the vent tube drain hose
• Loose or rough turning bearing. • Impeller rubs either the water pump body or water pump adapter.
RADIATOR CLEANING
The radiator and air conditioning fins should be cleaned when an accumulation of bugs, leaves etc. has occurred. Clean radiator fins are necessary for good heat transfer. 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.
FAN BLADE
INSPECTION
The fan cannot be repaired. If fan is damaged, it must be replaced. Inspect fan as follows:
(1) Remove fan blade and viscous fan drive as an assembly from the engine.
(2) Remove fan blade assembly from viscous fan drive unit (four bolts) (Fig. 25).
(3) Lay fan on a flat surface with leading edge facing down. With tip of blade touching flat surface, replace fan if clearance between opposite blade and surface is greater than 2.0 mm (.090 inch). Rocking motion of opposite blades should not exceed 2.0 mm (.090 inch). Test all blades in this manner.
WARNING: DO NOT ATTEMPT TO BEND OR STRAIGHTEN FAN BLADES IF NOT WITHIN SPECI- FICATIONS.
(4) Inspect fan assembly for cracks, bends, loose rivets or broken welds. Replace fan if any damage is found.
CAUTION: If fan blade assembly is replaced because of mechanical damage, the fan pulley bearing and viscous fan drive should also be inspected. These components could have been damaged due to excessive vibration.
CAUTION: Some engines equipped with serpentine drive belts have reverse rotating fans and viscous fan drives. They are marked with the word REVERSE to designate their usage. Installation of the wrong fan or viscous fan drive can result in engine overheating.
COOLING SYSTEM CLEANING/REVERSE FLUSHING
CAUTION: The cooling system normally operates at 90-to-117 kPa (13- to-17 psi) pressure. Exceeding this pressure may damage the radiator or hoses.
CLEANING
Drain cooling system and refill with water. Run engine with coolant tank pressure/vent cap installed until upper radiator hose is hot. Stop engine and drain water from system. If water is dirty, fill system with water, run engine and drain system. Repeat until water drains clean.
REVERSE FLUSHING
Reverse flushing of the cooling system is the forcing of water through the cooling system. This is done using air pressure in the opposite direction of normal coolant flow. It is usually only necessary with very dirty systems with evidence of partial plugging.
REVERSE FLUSHING RADIATOR
Disconnect the radiator hoses from the radiator fittings. Attach a section of radiator hose to the radiator bottom outlet fitting and insert the flushing gun.
Connect a water supply hose and air supply hose to the flushing gun.
CAUTION: The cooling system normally operates at 90-to-117 kPa (13- to-17 psi) pressure. Exceeding this pressure may damage the radiator or hoses.
Allow the coolant tank and radiator to fill with water. When radiator is filled, apply air in short blasts allowing radiator to refill between blasts. Continue this reverse flushing until clean water flows out through rear of radiator cooling tube passages. For more information, refer to operating instructions supplied with flushing equipment. Have radiator cleaned more extensively by a radiator repair shop.
REVERSE FLUSHING ENGINE
Drain the cooling system. Remove the thermostat housing and thermostat. Install the thermostat housing. Disconnect the radiator upper hose from the radiator and attach the flushing gun to the hose. Disconnect the radiator lower hose from the water pump. Attach a lead away hose to the water pump inlet fitting.
CAUTION: Be sure that the heater water control valve is closed (heat off). This is done to prevent coolant flow with scale and other deposits from entering the heater core.
Connect the water supply hose and air supply hose to the flushing gun. Allow the engine to fill with water. When the engine is filled, apply air in short blasts, allowing the system to fill between air blasts. Continue until clean water flows through the lead away hose. For more information, refer to operating instructions supplied with flushing equipment. Remove the lead away hose, flushing gun, water supply hose and air supply hose. Remove the thermostat housing and install thermostat. Install the thermostat housing with a new replacement rubber seal. Refer to Thermostat Installation. Connect the radiator hoses. Refill the cooling system with the correct antifreeze/water mixture.
CHEMICAL CLEANING
In some instances, use a radiator cleaner (Mopar Radiator Kleen or equivalent) before flushing. This will soften scale and other deposits and aid the flushing operation.
CAUTION: Be sure instructions on the container are followed.
ADJUSTMENTS
DRIVE BELT TENSION
Initial belt adjustment is done with a adjustable tensioner pulley. After the initial adjustment is performed, an automatic belt tensioner is used to maintain correct belt tension at all times. For other tensioner information and removal/installation procedures, refer to Automatic Belt Tensioner in this group. Due to use of this belt tensioner, DO NOT attempt to use a belt tension gauge on the 2.5L diesel engine.
SPECIFICATIONS
COOLING SYSTEM CAPACITY
2.5L Diesel Engine: 9.8 Liters (10.4 qts.)
THERMOSTAT
Starts to open at 80°C (176°F).
TORQUE SPECIFICATIONS
DESCRIPTION TORQUE Automatic Belt Tensioner-to-Mounting Bracket Bolt (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 N·m Automatic Belt Tensioner to Block Bolts (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 N·m Coolant Tank Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 N·m Fan Shroud-to-Radiator Mounting Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 N·m Fan Blade-to-Thermal Viscous Fan Drive Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 N·m Hose Clamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 N·m Radiator-to-A/C Condenser Isolator Nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 N·m Thermal Viscous Fan Drive-to-Fan Hub Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 N·m Thermostat Housing Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 N·m Water Pump Mounting Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 N·m Water Pump Pulley Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 N·m