2003 JEEP GRAND CHEROKEE oil cooler

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

COOLING
TABLE OF CONTENTS
page page
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM 4.7L
ENGINE..............................1
DESCRIPTION - COOLING SYSTEM
ROUTING 4.7L ENGINE..................1
DESCRIPTIONÐCOOLING SYSTEM 4.0L
ENGINE..............................1
DESCRIPTIONÐCOOLING SYSTEM
ROUTING 4.0L ENGINE..................1
DESCRIPTIONÐHOSE CLAMPS...........1
OPERATION
OPERATIONÐCOOLING SYSTEM.........2
OPERATIONÐHOSE CLAMPS............2
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)...................3
DIAGNOSIS AND TESTINGÐPRELIMINARY
CHECKS.............................3
DIAGNOSIS AND TESTING - COOLING
SYSTEM DIAGNOSIS CHART.............5
DIAGNOSIS AND TESTING - COOLING
SYSTEM LEAKS......................10DIAGNOSIS AND TESTING - COOLING
SYSTEM DEAERATION.................12
STANDARD PROCEDURE
STANDARD PROCEDUREÐDRAINING
COOLING SYSTEM 4.7L ENGINE.........12
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 4.7L ENGINE.........12
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM - 4.0L ENGINE........13
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM - 4.0L ENGINE........13
STANDARD PROCEDURE - ADDING
ADDITIONAL COOLANT.................13
STANDARD PROCEDURE - COOLING
SYSTEM - REVERSE FLUSHING..........14
SPECIFICATIONS
TORQUE............................14
SPECIAL TOOLS
COOLING...........................15
ACCESSORY DRIVE......................16
ENGINE...............................24
TRANSMISSION.........................55
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM 4.7L
ENGINE
The cooling system consists of the following items:
²Hydraulic cooling fan and fan drive assembly
²Radiator
²Power steering oil cooler
²Radiator pressure cap
²Thermostat
²Coolant reserve/overflow system
²Transmission oil cooler (if equipped with an
automatic transmission)
²Coolant
²Water pump
²Hoses and hose clamps
DESCRIPTION - COOLING SYSTEM ROUTING
4.7L ENGINE
For cooling system routing refer to (Fig. 1).
DESCRIPTIONÐCOOLING SYSTEM 4.0L
ENGINE
The cooling system consists of:
²A radiator
²Mechanical Cooling Fan
²Thermal viscous fan drive-Low disengaged
²Fan shroud (Fig. 2)
²Radiator pressure cap
²Thermostat
²Coolant reserve/overflow system
²Transmission oil cooler (if equipped with an
automatic transmission)
²Coolant
²Water pump
²Hoses and hose clamps
²Accessory drive belt
DESCRIPTIONÐCOOLING SYSTEM ROUTING
4.0L ENGINE
For cooling system routing refer to (Fig. 3).
DESCRIPTIONÐHOSE CLAMPS
The cooling system utilizes both worm drive and
spring type hose clamps. If a spring type clamp
WJCOOLING 7 - 1

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)

²Fan control valve
²Two stage G-rotor hydraulic drive
The hydraulic fan and drive is not serviceable.
Therefore any failure of the fan blade, hydraulic fan
drive or fan shroud requires replacement of the fan
module because the fan blade and hydraulic fan drive
are matched and balanced as a system and servicing
either separately would disrupt this balance.
For hydraulic fluid routing information refer to
(Fig. 5).
CAUTION: Do not attempt to service the hydraulic
cooling fan or fan drive separately replace the cooling
module as an assembly. Failure to do so may cause
severe damage to the hydraulic cooling fan assembly.
OPERATION
The hydraulic radiator cooling fan used on the
Grand Cherokee with the 4.7L engine replaces both
the electric fan and the engine driven mechanical
fan. The use of this hydraulic fan provides the 4.7L
equipped Grand Cherokee with heavy trailer tow
capability while at the same time reducing unneces-
sary power drain on both the engine and the vehicles
electrical system.
HYDRAULIC FAN STRATEGY
The hydraulic radiator cooling fan is controlled by
the JTEC. A PWM (Pulse With Modulated) signal
from the JTEC controls the fan from 0 to 100% of the
available fan speed. There are four inputs to the
JTEC that determine what speed percentage of fan is
required by the vehicle. These inputs are:
²Engine Coolant Temperature
²Transmission Oil Temperature
²Battery Temperature
²A/C System Pressure
By monitoring these four parameters, the JTEC
can determine if cooling airflow is required. If airflow
is required, the JTEC will slowly ramp up (speed up)
the fan speed until the parameter(s) are under con-
trol. Once the temperature or pressure is reduced to
within operating parameters the fan will ramp up,
ramp down, or hold its speed to maintain the temper-
ature / pressure requirements.
NOTE: Even if the JTEC is not requesting fan on
operation the fan blade will usually spin between
100 and 500 RPM when the vehicle is at idle. This is
due to a controlled minimum oil flow requirement
through the fan drive motor.
ACTIVATING THE HYDRAULIC FAN WITH THE DRB
Under the Engine Systems test heading, there is a
subheading. ªHydraulic fan solenoid testº, that has
the selections, on /off. Activating the fan with the
DRB will run the fan at 100% duty cycle, which will
help troubleshoot any system problems, and also help
with the deaeration procedure.
NOTE: Engine must be running to activate the fan
with the DRB.
RADIATOR COOLING FAN HYDRAULIC FLUID PATH
Hydraulic fluid is pumped through the power
steering pump, from the pump the fluid travels
though a high pressure delivery line to the fan drive
motor. As fluid is diverted through the G-rotors, rota-
tional motion is created as fluid moves from the high-
pressure (inlet) side of the motor to the low-pressure
(outlet) side. Fluid exiting the drive motor is divided
into two paths. Path one continues through a high
pressure delivery line to the vehicles steering gear to
provide steering assist. and path two sends fluid
back to the power steering pump through a low pres-
sure line. Fluid exits the steering gear under low
pressure and travels through a low pressure line to
the power steering fluid cooler to be cooled before
being returned back the the power steering fluid res-
ervoir (Fig. 5).
Fig. 4 HYDRAULIC RADIATOR COOLING FAN AND
FAN DRIVE
1 - POWER STEERING FLUID COOLER
2 - RADIATOR
3 - HIGH PRESSURE LINE FROM STEERING GEAR PUMP TO
HYDRAULIC FAN MOTOR
4 - HYDRAULIC FAN MOTOR
5 - HIGH PRESSURE LINE FROM HYDRAULIC FAN MOTOR TO
STEERING GEAR
6 - FAN SHROUD
7 - 28 ENGINEWJ
RADIATOR FAN - 4.7L (Continued)

NOTE: There is a steering flow control valve located
in the fan drive motor. This valve operates like the
flow control valve found in the typical power steer-
ing pump. Because of the design of the valve steer-
ing assist can not be effected by the radiator
cooling fan even during fan drive failure.
REMOVAL
(1) Raise vehicle on hoist.
(2) Drain cooling system.(Refer to 7 - COOLING -
STANDARD PROCEDURE)
NOTE: The hydraulic fan drive is driven by the
power steering pump. When removing lines or
hoses from fan drive assembly use a drain pan to
catch any power steering fluid that may exit the fan
drive or the lines and hoses.NOTE: When ever the high pressure line fittings are
removed from the hydraulic fan drive the O-rings
must be replaced.
(3) Disconnect two high pressure lines at hydraulic
fan drive (Fig. 6). Remove and discard o-rings from
line fittings.
(4) Disconnect low pressure return hose at hydrau-
lic fan drive (Fig. 6).
NOTE: The lower mounting bolts can only be
accessed from under vehicle.
(5) Remove two lower mounting bolts from the
shroud (Fig. 8).
(6) Lower vehicle.
(7) Disconnect the electrical connector for the fan
control solenoid.
(8) Disconnect the radiator upper hose at the radi-
ator and position out of the way.
(9) Disconnect the power steering gear outlet hose
and fluid return hose at the cooler (Fig. 7).
Fig. 5 HYDRAULIC FAN FLUID FLOW CIRCUIT
1 - POWER STEERING RESERVOIR
2 - POWER STEERING PUMP
3 - HYDRAULIC FAN DRIVE ASSEMBLY
4 - FAN BLADE5 - HYDRAULIC FAN CONTROL SOLENOID
6 - POWER STEERING OIL COOLER
7 - STEERING GEAR
WJENGINE 7 - 29
RADIATOR FAN - 4.7L (Continued)

(9) Disconnect the overflow hose from radiator
(Fig. 41).
(10) Remove the air inlet duct at the grill.
(11) The lower part of radiator is equipped with
two alignment dowel pins (Fig. 40). 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 REFRIG-
ERANT WARNINGS IN GROUP 24, HEATING AND
AIR CONDITIONING BEFORE HANDLING ANY AIR
CONDITIONING COMPONENT.
(12) If equipped with an auxiliary automatic trans-
mission oil cooler, use caution when removing radia-
tor. The oil cooler lines are routed through a rubber
air seal on the right side of radiator. Do not cut or
tear this seal.
(13) Gently lift up and remove radiator from vehi-
cle. Be careful not to scrape the radiator fins against
any other component. Also be careful not to disturb
the air conditioning condenser (if equipped).
CLEANING
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 con-
denser of debris.
Fig. 39 Air Seals - Typical
1 - AIR DAM
2 - RADIATOR
3 - AIR DAM
4 - A/C CONDENSER
5 - AIR SEAL
Fig. 40 Radiator Alignment Dowels
1 - RADIATOR
2 - ALIGNMENT DOWEL
3 - RADIATOR LOWER ISOLATOR
4 - RADIATOR LOWER CROSSMEMBER
Fig. 41 Radiator, Shroud and Electric Fan
1 - RADIATOR/SHROUD/FAN ASSEMBLY
2 - OVER FLOW HOSE
3 - ELECTRIC FAN CONNECTOR
4 - RADIATOR MOUNTING BOLT(S)
5 - CLAMP
7 - 46 ENGINEWJ
RADIATOR - 4.0L (Continued)

TRANSMISSION
TABLE OF CONTENTS
page page
TRANS COOLER
DESCRIPTION.........................55STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES.................55
TRANS COOLER
DESCRIPTION
An internal high capacity/high efficiency cooler is
used on all vehicles these coolers are an oil-to-coolant
type which consists of plates mounted in the radiator
outlet tank (Fig. 36). Because the internal oil cooler
is so efficient, no auxiliary oil cooler is offered The
cooler is not servicable seperatly from the radiator.
STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES
When a transmission failure has contaminated the
fluid, the oil cooler(s) must be flushed. The torque
converter must also be replaced. This will insure that
metal particles or sludged oil are not later trans-
ferred back into the reconditioned (or replaced) trans-
mission.
The only recommended procedure for flushing cool-
ers and lines is to use Tool 6906-B Cooler Flusher.
WARNING: WEAR PROTECTIVE EYEWEAR THAT
MEETS THE REQUIREMENTS OF OSHA AND ANSI
Z87.1±1968. WEAR STANDARD INDUSTRIAL RUB-
BER GLOVES.
KEEP LIGHTED CIGARETTES, SPARKS, FLAMES,
AND OTHER IGNITION SOURCES AWAY FROM THE
AREA TO PREVENT THE IGNITION OF COMBUSTI-
BLE LIQUIDS AND GASES. KEEP A CLASS (B) FIRE
EXTINGUISHER IN THE AREA WHERE THE
FLUSHER WILL BE USED.
KEEP THE AREA WELL VENTILATED.
DO NOT LET FLUSHING SOLVENT COME IN CON-
TACT WITH YOUR EYES OR SKIN: IF EYE CONTAM-
INATION OCCURS, FLUSH EYES WITH WATER FOR
15 TO 20 SECONDS. REMOVE CONTAMINATED
CLOTHING AND WASH AFFECTED SKIN WITH
SOAP AND WATER. SEEK MEDICAL ATTENTION.
(1) Remove cover plate filler plug on Tool 6906-B.
Fill reservoir 1/2 to 3/4 full of fresh flushing solution.
Flushing solvents are petroleum based solutions gen-
erally used to clean automatic transmission compo-
nents.DO NOTuse solvents containing acids, water,
gasoline, or any other corrosive liquids.(2) Reinstall filler plug on Tool 6906-B.
(3) Verify pump power switch is turned OFF. Con-
nect red alligator clip to positive (+) battery post.
Connect black (-) alligator clip to a good ground.
(4) Disconnect the cooler lines at the transmission.
NOTE: When flushing transmission cooler and
lines, ALWAYS reverse flush.
NOTE: The converter drainback valve must be
removed and an appropriate replacement hose
installed to bridge the space between the transmis-
sion cooler line and the cooler fitting. Failure to
remove the drainback valve will prevent reverse
flushing the system. A suitable replacement hose
can be found in the adapter kit supplied with the
flushing tool.
(5) Connect the BLUE pressure line to the OUT-
LET (From) cooler line.
(6) Connect the CLEAR return line to the INLET
(To) cooler line
(7) Turn pump ON for two to three minutes to
flush cooler(s) and lines.
(8) Turn pump OFF.
(9) Disconnect CLEAR suction line from reservoir
at cover plate. Disconnect CLEAR return line at
cover plate, and place it in a drain pan.
(10) Turn pump ON for 30 seconds to purge flush-
ing solution from cooler and lines. Turn pump OFF.
(11) Place CLEAR suction line into a one quart
container of MopartATF +4, type 9602, Automatic
Transmission Fluid.
(12) Turn pump ON until all transmission fluid is
removed from the one quart container and lines. This
purges any residual cleaning solvent from the trans-
mission cooler and lines. Turn pump OFF.
(13) Disconnect alligator clips from battery. Recon-
nect flusher lines to cover plate, and remove flushing
adapters from cooler lines.
WJTRANSMISSION 7 - 55

SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
31). The increase in electrode gap will be consider-
ably in excess of 0.001 inch per 2000 miles of opera-
tion. This suggests that a plug with a cooler heat
range rating should be used. Over advanced ignition
timing, detonation and cooling system malfunctions
can also cause spark plug overheating.
CAUTION: If the engine is equipped with copper
core ground electrode, or platinum tipped spark
plugs, they must be replaced with the same type/
number spark plug as the original. If another spark
plug is substituted, pre-ignition will result.
REMOVAL
CAUTION: If equipped with a 4.7L H.O. (High-Out-
put) engine, never substitute the original platinum
tipped spark plug with a different part number. Seri-
ous engine damage may result.
On the 4.0L 6±cylinder engine, the spark plugs are
located below the coil rail assembly. On the 4.7L V±8
engine, each individual spark plug is located under
each ignition coil.
(1) 4.0L 6±Cylinder Engine: Prior to removing
spark plug, spray compressed air around spark plug
hole and area around spark plug. This will help pre-
vent foreign material from entering combustion
chamber.
(2) 4.7L V±8 Engine: Prior to removing spark plug,
spray compressed air around base of ignition coil at
cylinder head. This will help prevent foreign material
from entering combustion chamber.
(3) On the 4.0L engine the coil rail assembly must
be removed to gain access to any/all spark plug.
Refer to Ignition Coil Removal/Installation. On the4.7L V-8 engine each individual ignition coil must be
removed to gain access to each spark plug. Refer to
Ignition Coil Removal/Installation.
(4) Remove spark plug from cylinder head using a
quality socket with a rubber or foam insert. If
equipped with a 4.7L V-8 engine, also check condition
of coil o-ring and replace as necessary.
(5) Inspect spark plug condition. Refer to Spark
Plug Conditions.
CLEANING
Except 4.7L H.O. Engine:The plugs may be
cleaned using commercially available spark plug
cleaning equipment. After cleaning, file center elec-
trode flat with a small point file or jewelers file
before adjusting gap.
CAUTION: Never use a motorized wire wheel brush
to clean spark plugs. Metallic deposits will remain
on spark plug insulator and will cause plug misfire.
4.7L H.O. Engine:Never clean spark plugs on the
4.7L H.O. engine. Damage to the platinum rivet on
the center electrode will result.
INSTALLATION
CAUTION: The standard 4.7L V-8 engine is
equipped with copper core ground electrode spark
plugs. They must be replaced with the same type/
number spark plug as the original. If another spark
plug is substituted, pre-ignition will result.
CAUTION: If equipped with a 4.7L H.O. (High-Out-
put) engine, never substitute the original platinum
tipped spark plug with a different type/part number.
Serious engine damage may result.
Special care should be taken when installing spark
plugs into cylinder head spark plug wells. Be sure
plugs do not drop into plug wells as ground straps
may be bent resulting in a change in plug gap, or
electrodes can be damaged.
Always tighten spark plugs to specified torque. Over
tightening can cause distortion resulting in a change
in spark plug gap or a cracked porcelain insulator.
(1) Start spark plug into cylinder head by hand to
avoid cross threading.
(2) 4.0L 6±Cylinder Engine: Tighten spark plugs to
35-41 N´m (26-30 ft. lbs.) torque.
(3) 4.7L V±8 Engine: Tighten spark plugs to 27
N´m (20 ft. lbs.) torque.
(4)
4.7L V±8 Engine: Before installing coil(s), check
condition of coil o-ring and replace as necessary. To aid
in coil installation, apply silicone to coil o-ring.
(5) Install ignition coil(s). Refer to Ignition Coil
Removal/Installation.
Fig. 31 SPARK PLUG OVERHEATING
1 - BLISTERED WHITE OR GRAY COLORED INSULATOR
8I - 18 IGNITION CONTROLWJ
SPARK PLUG (Continued)