obs JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual

LUBRICATION & MAINTENANCE
TABLE OF CONTENTS
page page
LUBRICATION & MAINTENANCE
SPECIFICATIONS - FLUID CAPACITIES.......1
INTERNATIONAL SYMBOLS
DESCRIPTION..........................2
PARTS & LUBRICANT RECOMMENDATION
STANDARD PROCEDURE - PARTS &
LUBRICANT RECOMMENDATIONS.........2
FLUID TYPES
DESCRIPTION
DESCRIPTION - ENGINE COOLANT........2
DESCRIPTION - ENGINE COOLANT........3
ENGINE OIL..........................4
DESCRIPTION - ENGINE OIL.............4
DESCRIPTION........................5
DESCRIPTION - TRANSFER CASE - NV242 . . 5
DESCRIPTION - TRANSFER CASE - NV247 . . 5
DESCRIPTION - AUTOMATIC
TRANSMISSION FLUID..................5
DESCRIPTION - ENGINE OIL - DIESEL
ENGINES............................6OPERATION - AUTOMATIC TRANSMISSION
FLUID...............................6
FLUID FILL/CHECK LOCATIONS
INSPECTION - FLUID FILL/CHECK
LOCATIONS..........................6
MAINTENANCE SCHEDULES
DESCRIPTION..........................6
LIFT POINTS
STANDARD PROCEDURE - HOISTING AND
JACKING RECOMMENDATIONS...........6
JUMP STARTING
STANDARD PROCEDURE - JUMP STARTING . . 7
EMERGENCY TOW HOOKS
DESCRIPTION..........................8
TOWING
STANDARD PROCEDURE - TOWING
RECOMMENDATIONS...................8
LUBRICATION &
MAINTENANCE
SPECIFICATIONS - FLUID CAPACITIES
DESCRIPTION SPECIFICATION
FUEL TANK 20 U.S. Gallons (76
Liters)****
Engine Oil - with Filter -
2.7L Diesel6.5L (6.9 qts.)
Engine Oil - with Filter -
4.0L5.7 L (6.0 qts.)
Engine Oil - with Filter -
4.7L5.7 L (6.0 qts.)
Cooling System - 2.7L
Diesel14.2L (15 qts.)***
Cooling System - 4.0L 14.1 L (15 qts.)***
Cooling System - 4.7L 13.7 L (14.5 qts.)***
AUTOMATIC TRANSMISSION
Service Fill - 42RE 3.8 L (4.0 qts.)
Service Fill - 545RFE 2WD - 5.2 L (11 pts.)
4WD - 6.2 L (13 pts.)
O-haul Fill - 42RE 9.1-9.5 L (19-20 pts.)
DESCRIPTION SPECIFICATION
O-haul Fill - 545RFE 13.33 L (28.0 pts.)
Dry fill capacity Depending on type and size of internal
cooler, length and inside diameter of cooler lines, or use
of an auxiliary cooler, these figures may vary. (Refer to
appropriate 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC/FLUID - STANDARD PROCEDURE).
TRANSFER CASE
NV242 1.35L (2.85 pts.)
NV247 1.6L (3.4 pts.)
FRONT AXLE   0.3 L (1 oz.)
186 FBI (Model 30) 1.18 L (2.5 pts.)*
* With Vari-Lok add 0.07 L (2.5 oz.) of Friction Modifier.
REAR AXLE   0.3 L (1 oz.)
198 RBI (Model 35) 1.66 L (3.5 pts.)*
226 RBA (Model 44) 2.24 L (4.75 pts.)**
* With Trac-lok add 0.07 L (2.5 oz.) of Friction Modifier.
** With Trac-lok or Vari-Lok, add 0.07 L (2.5 oz.) of
Friction Modifier.
*** Includes 0.9L (1.0 qts.) for coolant reservoir.
****Nominal refill capacities are shown. A variation may
be observed from vehicle to vehicle due to
manufacturing tolerance and refill procedure.
WJLUBRICATION & MAINTENANCE 0 - 1

DISCONNECT CABLE CLAMPS AS FOLLOWS:
²Disconnect BLACK cable clamp from engine
ground on disabled vehicle.
²When using a Booster vehicle, disconnect
BLACK cable clamp from battery negative terminal.
Disconnect RED cable clamp from battery positive
terminal.
²Disconnect RED cable clamp from battery posi-
tive terminal on disabled vehicle.
EMERGENCY TOW HOOKS
DESCRIPTION
WARNING: REMAIN AT A SAFE DISTANCE FROM A
VEHICLE THAT IS BEING TOWED VIA ITS TOW
HOOKS. THE TOW STRAPS/CHAINS COULD BREAK
AND CAUSE SERIOUS INJURY.
Some Jeep vehicles are equipped with front emer-
gency tow hooks (Fig. 9). The tow hooks should be
used forEMERGENCYpurposes only.
CAUTION: DO NOT use emergency tow hooks for
tow truck hook-up or highway towing.
TOWING
STANDARD PROCEDURE - TOWING
RECOMMENDATIONS
A vehicle equipped with SAE approved wheel lift-
type towing equipment can be used to tow WJ vehi-
cles. When towing a 4WD vehicle using a wheel-lift
towing device, use tow dollies under the opposite end
of the vehicle. A vehicle with flatbed device can also
be used to transport a disabled vehicle (Fig. 10).
SAFETY PRECAUTIONS
CAUTION: The following safety precautions must be
observed when towing a vehicle:
²Secure loose and protruding parts.
²Always use a safety chain system that is inde-
pendent of the lifting and towing equipment.
Fig. 8 Jumper Cable Clamp Connections
1 - ENGINE GROUND
2 - NEGATIVE JUMPER CABLE
3 - BATTERY NEGATIVE CABLE
4 - POSITIVE JUMPER CABLE
5 - BATTERY POSITIVE CABLE
6 - BATTERY
7 - TEST INDICATOR
Fig. 9 Emergency Tow Hooks
1 - TOW HOOK
Fig. 10 Tow Vehicles With Approved Equipment
0 - 8 LUBRICATION & MAINTENANCEWJ
JUMP STARTING (Continued)

²Do not allow towing equipment to contact the
disabled vehicle's fuel tank.
²Do not allow anyone under the disabled vehicle
while it is lifted by the towing device.
²Do not allow passengers to ride in a vehicle
being towed.
²Always observe state and local laws regarding
towing regulations.
²Do not tow a vehicle in a manner that could
jeopardize the safety of the operator, pedestrians or
other motorists.
²Do not attach tow chains, T-hooks, or J-hooks to
a bumper, steering linkage, drive shafts or a non-re-
inforced frame hole.
²Do not tow a heavily loaded vehicle. Use a flat-
bed device to transport a loaded vehicle.
TWO-WHEEL-DRIVE VEHICLE TOWING
DaimlerChrysler Corporation recommends that a
vehicle be towed with the rear end lifted, whenever
possible.
WARNING: WHEN TOWING A DISABLED VEHICLE
AND THE DRIVE WHEELS ARE SECURED IN A
WHEEL LIFT OR TOW DOLLIES, ENSURE THE
TRANSMISSION IS IN THE PARK POSITION (AUTO-
MATIC TRANSMISSION) OR A FORWARD DRIVE
GEAR (MANUAL TRANSMISSION).
WARNING: ENSURE VEHICLE IS ON A LEVEL SUR-
FACE OR THE WHEELS ARE BLOCKED TO PRE-
VENT VEHICLE FROM ROLLING.
TWO WHEEL DRIVE TOWING-REAR END LIFTED
CAUTION: Do not use steering column lock to
secure steering wheel during towing operation.
2WD vehicles can be towed with the front wheels
on the surface for extended distances at speeds not
exceeding 48 km/h (30 mph).
(1) Attach wheel lift device to rear wheels.
(2) Place the transmission in neutral.
(3) Raise vehicle to towing position.
(4) Attach safety chains. Route chains so not to
interfere with tail pipe when vehicle is lifted.
(5) Turn the ignition switch to the OFF position to
unlock the steering wheel.
CAUTION: Do not use steering column lock to
secure steering wheel during towing operation.
(6) Secure steering wheel in straight ahead posi-
tion with a clamp device designed for towing.
(7) Place transmission in park.
TWO WHEEL DRIVE TOWING-FRONT END LIFTED
CAUTION: Many vehicles are equipped with air
dams, spoilers, and/or ground effect panels. To
avoid component damage, a wheel-lift towing vehi-
cle or a flat-bed hauling vehicle is recommended.
(1) Attach wheel lift device to rear wheels.
(2) Place the transmission in neutral.
(3) Raise the rear of the vehicle off the ground and
install tow dollies under rear wheels.
(4) Attach wheel lift device to front wheels and
raise vehicle to towing position.
(5) Attach the safety chains.
CAUTION: Do not use steering column lock to
secure steering wheel during towing operation.
(6) Turn the ignition switch to the OFF position to
unlock the steering wheel.
(7) Secure steering wheel in straight ahead posi-
tion with a clamp device designed for towing.
(8) Place transmission in park.
FOUR-WHEEL-DRIVE VEHICLE TOWING
DaimlerChrysler Corporation recommends that a
4WD vehicle be transported on a flat-bed device. A
Wheel-lift device can be used providedthe trailing
wheels are off the ground and positioned in
tow dollies.
WARNING: WHEN TOWING A DISABLED VEHICLE
AND THE DRIVE WHEELS ARE SECURED IN A
WHEEL LIFT OR TOW DOLLIES, ENSURE THE
TRANSMISSION IS IN THE PARK POSITION.
CAUTION: Many vehicles are equipped with air
dams, spoilers, and/or ground effect panels. To
avoid component damage, a wheel-lift towing vehi-
cle or a flat-bed hauling vehicle is recommended.
FOUR WHEEL DRIVE TOWINGÐREAR END LIFTED
WARNING: ENSURE VEHICLE IS ON A LEVEL SUR-
FACE OR THE WHEELS ARE BLOCKED TO PRE-
VENT VEHICLE FROM ROLLING.
(1) Attach wheel lift device to front wheels.
(2) Place the transmission in neutral.
(3) Raise the front of the vehicle off the ground
and install tow dollies under front wheels.
(4) Attach wheel lift device to rear wheels and
raise vehicle to towing position.
(5) Attach safety chains. Route chains so not to
interfere with tail pipe when vehicle is lifted.
WJLUBRICATION & MAINTENANCE 0 - 9
TOWING (Continued)

OPERATION
The master cylinder bore contains a primary and
secondary piston. The primary piston supplies
hydraulic pressure to the front brakes. The secondary
piston supplies hydraulic pressure to the rear brakes.
The master cylinder reservoir stores reserve brake
fluid for the hydraulic brake circuits.
DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER
NOTE: Inspect and repair any external fluid leaks
before performing test.
(1) Start engine and check booster vacuum hose
connections. A hissing noise indicates vacuum leak.
Correct any vacuum leak before proceeding.
(2)
Stop engine and shift transmission into Neutral.
(3) Pump brake pedal until all vacuum reserve in
booster is depleted.
(4) Press and hold brake pedal under light foot
pressure. The pedal should hold firm, if the pedal
falls away the master cylinder or HCU may be faulty
(internal leakage).
(5) Start engine and note pedal action. It should
fall away slightly under light foot pressure then hold
firm. If no pedal action is discernible, power booster,
vacuum supply, or vacuum check valve is faulty. Pro-
ceed to the POWER BOOSTER VACUUM TEST.
(6) If the POWER BOOSTER VACUUM TEST
passes, rebuild booster vacuum reserve as follows:
Release brake pedal. Increase engine speed to 1500
rpm, close the throttle and turn off the engine.
(7) Wait a minimum of 90 seconds and try brake
action again. Booster should provide two or more vac-
uum assisted pedal applications. If vacuum assist is
not provided, some component of the booster is faulty.
POWER BOOSTER VACUUM TEST
(1) Connect vacuum gauge to booster check valve
with short length of hose and T-fitting (Fig. 48).
(2) Start and run engine at curb idle speed for one
minute.
(3) Observe the vacuum supply. If vacuum supply
is not adequate, repair vacuum supply.
(4) Clamp hose shut between vacuum source and
check valve.
(5) Stop engine and observe vacuum gauge.
(6) If vacuum drops more than one inch HG (33
millibars) within 15 seconds, booster diaphragm,
check valve or check valve seal/grommet is faulty.
POWER BOOSTER CHECK VALVE TEST
(1) Disconnect vacuum hose from check valve.
(2)
Remove check valve and valve seal from booster.
(3) Use a hand operated vacuum pump for test.(4) Apply 51-67 kPa (15-20 in.) vacuum at large
end of check valve (Fig. 49).
(5) Vacuum should hold steady. If gauge on pump
indicates vacuum loss the check valve and seal
should be replaced.
Fig. 48 Typical Booster Vacuum Test Connections
1 - TEE FITTING
2 - SHORT CONNECTING HOSE
3 - CHECK VALVE
4 - CHECK VALVE HOSE
5 - CLAMP TOOL
6 - INTAKE MANIFOLD
7 - VACUUM GAUGE
Fig. 49 Vacuum Check Valve And Seal
1 - BOOSTER CHECK VALVE
2 - APPLY TEST VACUUM HERE
3 - VALVE SEAL
5 - 24 BRAKES - BASEWJ
MASTER CYLINDER (Continued)

DIAGNOSIS AND TESTING - COOLING SYSTEM DIAGNOSIS CHART
COOLING SYSTEM DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE GAUGE
READS LOW1. Has a Diagnostic Trouble Code
(DTC) been set indicating a stuck
open thermostat?1. Refer to (Refer to 25 - EMISSIONS
CONTROL - DESCRIPTION) for On-Board
Diagnostics and DTC information. Replace
thermostat if necessary.
2. Is the temperature sending unit
connected?2. Check the temperature sensor connector.
(Refer to 7 - COOLING/ENGINE/ENGINE
COOLANT TEMP SENSOR -
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
reserve/overflow tank 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 24 - HEATING & AIR
CONDITIONING - DIAGNOSIS AND
TESTING)
TEMPERATURE GAUGE
READS HIGH OR THE
COOLANT LAMP
ILLUMINATES.
COOLANT MAY OR MAY
NOT BE LOST OR
LEAKING FROM THE
COOLING SYSTEM1. 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 reserve/
overflow tank and radiator?4. Check for coolant leaks and repair as
necessary. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
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
WJCOOLING 7 - 5
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
6. Poor seals at the radiator cap. 6. (a) Check condition of cap and cap seals.
(Refer to 7 - COOLING/ENGINE/RADIATOR
PRESSURE CAP - DIAGNOSIS AND
TESTING).
(b) Check condition of radiator filler
neck. If neck is bent or damaged,
replace radiator.
7. Coolant level low in radiator but
not in coolant reserve/overflow tank.
This means the radiator is not
drawing coolant from the coolant
reserve/overflow tank as the engine
cools7. (a) Check condition of radiator cap and
cap seals. (Refer to 7 - COOLING/ENGINE/
RADIATOR PRESSURE CAP - DIAGNOSIS
AND TESTING).
(b) Check condition of radiator filler neck. If
neck is bent or damaged, replace radiator.
(c) 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.
(d) Check coolant reserve/overflow tank and
tanks hoses for blockage. Repair as
necessary.
8. Incorrect coolant concentration 8. Check coolant. (Refer to 7 - COOLING/
ENGINE/COOLANT - DESCRIPTION) for
correct coolant/water mixture ratio.
9. Coolant not flowing through
system9. Check for coolant flow at radiator filler
neck with some coolant removed, engine
warm and thermostat open. Coolant should
be observed flowing through radiator. If flow
is not observed, determine area of
obstruction and repair as necessary.
10. Radiator or A/C condenser fins
are dirty or clogged.10. Remove insects and debris. (Refer to 7 -
COOLING/ENGINE/RADIATOR -
CLEANING).
11. Radiator core is corroded or
plugged.11. Have radiator re-cored or replaced.
12. Aftermarket A/C installed without
proper radiator.12. Install proper radiator.
13. Fuel or ignition system
problems.13. Refer to FUEL and /or IGNITION
CONTROL for diagnosis.
14. Dragging brakes. 14. Check and correct as necessary. (Refer
to 5 - BRAKES - DIAGNOSIS AND
TESTING) for correct procedures.
15. Bug screen or cardboard is
being used, reducing airflow.15. Remove bug screen or cardboard.
16. Thermostat partially or
completely shut.16. Check thermostat operation and replaces
necessary. (Refer to 7 - COOLING/ENGINE/
ENGINE COOLANT THERMOSTAT -
DIAGNOSIS AND TESTING).
7 - 6 COOLINGWJ
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
NOISY VISCOUS
FAN/DRIVE1. Fan blades loose - 4.0L. 1. Replace fan blade assembly. (Refer to 7 -
COOLING/ENGINE/RADIATOR FAN -
REMOVAL)
2. Fan blades striking a surrounding
object.2. Locate point of fan blade contact and
repair as necessary.
3. Air obstructions at radiator or air
conditioning condenser.3. Remove obstructions and/or clean debris
or insects from radiator or A/C condenser.
4. Thermal viscous fan drive has
defective bearing - 4.0L4. Replace fan drive. Bearing is not
serviceable. (Refer to 7 - COOLING/ENGINE/
RADIATOR FAN - REMOVAL).
INADEQUATE HEATER
PERFORMANCE.1.Thermostat failed in open position
2. Has a Diagnostic trouble Code
(DTC) been set?2. (Refer to 25 - EMISSIONS CONTROL -
DESCRIPTION) for correct procedures and
replace thermostat if necessary
3. Coolant level low 3. (Refer to 7 - COOLING - DIAGNOSIS
AND TESTING).
4. Obstructions in heater hose/
fittings4. Remove heater hoses at both ends and
check for obstructions
5. Heater hose kinked 5. Locate kinked area and repair as
necessary
6. 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.6. (Refer to 7 - COOLING/ENGINE/WATER
PUMP - DIAGNOSIS AND TESTING). If a
slipping belt is detected, (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE
BELTS - REMOVAL). If heater core
obstruction is detected, (Refer to 7 -
COOLING - STANDARD PROCEDURE) for
cooling system reverse flushing.
STEAM IS COMING
FROM THE FRONT OF
VEHICLE NEAR THE
GRILL 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 will evaporate when the
thermostat opens. This opening
allows heated water into the radiator.
When the moisture contacts the hot
radiator, 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 COLOR 1. 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. (Refer to 7 - COOLING/ENGINE/
COOLANT - DESCRIPTION) for coolant
concentration information. Adjust coolant
mixture as necessary.
WJCOOLING 7 - 9
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
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 DTC's. Verify sensor readings.
2. Fan control solenoid stuck9on9. 2. Check fan operation speeds. Refer to fan
speed operation table.
3. Fan control solenoid harness
damaged.3. Check for DTC 1499. Repair as required.
4. Transmission temperature too
high.4. Check for transmission over temp. DTC.
5. Engine coolant temperature too
high.5. (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.
DIAGNOSIS AND TESTING - COOLING SYSTEM
LEAKS
ULTRAVIOLET LIGHT METHOD
A leak detection additive is available through the
parts department that can be added to cooling sys-
tem. 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 can be used in conjunction with a
pressure tester to determine if any external leaks
exist (Fig. 5).
PRESSURE TESTER METHOD
The engine should be at normal operating temper-
ature. Recheck the system cold if cause of coolant
loss is not located during the warm engine examina-
tion.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING.
Fig. 5 Leak Detection Using Black LightÐTypical
1 - TYPICAL BLACK LIGHT TOOL
7 - 10 COOLINGWJ
COOLING (Continued)

Carefully remove radiator pressure cap from filler
neck 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, dirt and solder residue. Inspect radia-
tor-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 (Fig. 6).
Operate tester pump to apply 103.4 kPa (15 psi)
pressure to system. If hoses enlarge excessively or
bulges while testing, replace as necessary. Observe
gauge pointer and determine condition of cooling sys-
tem according to following criteria:
Holds Steady:If pointer remains steady for two
minutes, serious coolant leaks are not present in sys-
tem. 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 can-
not be detected, inspect for interior leakage or per-
form 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.INTERNAL LEAKAGE INSPECTION
Remove engine oil pan drain plug and drain a
small amount of engine oil. If coolant is present in
the pan, it will drain first because it is heavier than
oil. An alternative method is to operate engine for a
short period to churn the oil. After this is done,
remove engine dipstick and inspect for water glob-
ules. Also inspect transmission dipstick for water
globules and transmission fluid cooler for leakage.
WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 110 KPA (20 PSI). PRES-
SURE WILL BUILD UP QUICKLY IF A COMBUSTION
LEAK IS PRESENT. TO RELEASE PRESSURE,
ROCK TESTER FROM SIDE TO SIDE. WHEN
REMOVING TESTER, DO NOT TURN TESTER MORE
THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate engine without pressure cap on radiator
until thermostat opens. Attach a Pressure Tester to
filler neck. If pressure builds up quickly it indicates a
combustion leak exists. This is usually the result of a
cylinder head gasket leak or crack in engine. Repair
as necessary.
If there is not an immediate pressure increase,
pump the Pressure Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of gauge pointer indicates compression or
combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notremove spark plug cables or short
out cylinders to isolate compression leak.
If the needle on dial of pressure tester does not
fluctuate, race engine a few times to check for an
abnormal amount of coolant or steam. This would be
emitting from exhaust pipe. Coolant or steam from
exhaust pipe may indicate a faulty cylinder head gas-
ket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage into
cooling system is provided by a commercially avail-
able Block Leak Check tool. Follow manufacturers
instructions when using this product.
COMBUSTION LEAKAGE TEST - WITHOUT
PRESSURE TESTER
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat
removal. (Refer to 7 - COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT - REMOVAL). Remove
Fig. 6 Pressure Testing Cooling SystemÐTypical
1 - TYPICAL COOLING SYSTEM PRESSURE TESTER
WJCOOLING 7 - 11
COOLING (Continued)

accessory drive belt (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - REMOVAL).
Add coolant to radiator to bring level to within 6.3
mm (1/4 in) of top of thermostat housing.
CAUTION: Avoid overheating. Do not operate
engine for an excessive period of time. Open drain-
cock immediately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to
approximately 3000 rpm while observing coolant. If
internal engine combustion gases are leaking into
cooling system, bubbles will appear in coolant. If bub-
bles do not appear, internal combustion gas leakage
is not present.
DIAGNOSIS AND TESTING - COOLING SYSTEM
DEAERATION
As the engine operates, any air trapped in cooling
system gathers under the radiator cap. The next time
the engine is operated, thermal expansion of coolant
will push any trapped air past radiator cap into the
coolant reserve/overflow tank. Here it escapes to the
atmosphere into the tank. When the engine cools
down the coolant, it will be drawn from the reserve/
overflow tank into the radiator to replace any
removed air.
STANDARD PROCEDURE
STANDARD PROCEDUREÐDRAINING COOLING
SYSTEM 4.7L ENGINE
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS (Fig. 7) OR LOOSEN THE
RADIATOR DRAINCOCK WITH SYSTEM HOT AND
UNDER PRESSURE. SERIOUS BURNS FROM
COOLANT CAN OCCUR.
(1) DO NOT remove radiator cap first. With engine
cold, raise vehicle on a hoist and locate radiator
draincock.
NOTE: Radiator draincock is located on the left/
lower side of radiator facing to rear of vehicle.
(2) Attach one end of a hose to the draincock. Put
the other end into a clean container. Open draincock
and drain coolant from radiator. This will empty the
coolant reserve/overflow tank. The coolant does not
have to be removed from the tank unless the system
is being refilled with a fresh mixture. When tank is
empty, remove radiator cap and continue draining
cooling system.
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 4.7L ENGINE
(1) Tighten the radiator draincock and the cylinder
block drain plug(s) (if removed).
CAUTION: Failure to purge air from the cooling sys-
tem can result in an overheating condition and
severe engine damage.
(2) Remove the cooling system bleed plug from the
radiator upper hose inlet housing. (Fig. 8)Fill system
using a 50/50 mixture of ethylene-glycol antifreeze
and low mineral content water, until coolant begains
coming out of the cooling system bleed hole. Install
the cooling system bleed plug. Fill radiator to top and
install radiator cap. Add sufficient coolant to the
reserve/overflow tank to raise level to FULL mark.
(3) With heater control unit in the HEAT position,
operate engine with radiator cap in place.
(4) After engine has reached normal operating
temperature, shut engine off and allow it to cool.
When engine is cooling down, coolant will be drawn
into the radiator from the reserve/overflow tank.
(5) Add coolant to reserve/overflow tank as neces-
sary.Only add coolant to the reserve/overflow
tank when the engine is cold. Coolant level in a
warm engine will be higher due to thermal
expansion.To purge the cooling system of all air,
this heat up/cool down cycle (adding coolant to cold
engine) must be performed three times. Add neces-
sary coolant to raise tank level to the FULL mark
after each cool down period.
Fig. 7 Drain PlugÐ4.7L Engine
1 - CYLINDER BLOCK DRAIN PLUG
2 - EXHAUST MANIFOLD AND HEAT SHIELD
7 - 12 COOLINGWJ
COOLING (Continued)