pump - standard procedure JEEP GRAND CHEROKEE 2003 WJ / 2.G User Guide

the radiator to flush the radiator and/or A/C con-
denser of debris.
INSPECTION
The radiator cooling fins should be checked for
damage or deterioration. Inspect cooling fins to make
sure they are not bent or crushed, these areas result
in reduced heat exchange causing the cooling system
to operate at higher temperatures. Inspect the plastic
end tanks for cracks, damage or leaks.
Inspect the radiator neck for damage or distortion.
INSTALLATION
CAUTION: Before installing the radiator or A/C con-
denser, be sure the radiator-to-body and radiator-to-
A/C condenser rubber air seals (Fig. 39) are
properly fastened to their original positions. These
are used at the top, bottom and sides of the radia-
tor and A/C condenser. To prevent overheating,
these seals must be installed to their original posi-
tions.
(1) Equipped with air conditioning: Gently lower
the radiator and fan shroud into the vehicle. Guide
the two radiator alignment dowels through the holes
in the rubber air seals first and then through the A/C
support brackets (Fig. 40). Continue to guide thealignment dowels into the rubber grommets located
in lower radiator crossmember. The holes in the
L-shaped brackets (located on bottom of A/C con-
denser) must be positioned between bottom of rubber
air seals and top of rubber grommets.
(2) Connect the radiator upper and lower hoses
and hose clamps to radiator.
CAUTION: The tangs on the hose clamps must be
positioned straight down.
(3) Install coolant reserve/overflow tank hose at
radiator.
(4) Connect both transmission cooler lines at the
radiator.
(5) Install both radiator mounting bolts.
(6) Install air inlet duct at grill.
(7) Attach electric connector for hydraulic fan con-
trol solenoid.
(8) Install the grill (Refer to 23 - BODY/EXTERI-
OR/GRILLE - INSTALLATION).
(9) Connect the two high pressure lines to the
hydraulic fan drive. Tighten
1¤2in. pressure line fit-
ting to 49 N´m (36 ft. lbs.). and the 3/8 in. pressure
line fitting to 29 N´m (21.5 ft. lbs.).
(10) Connect the low pressure hose to the hydrau-
lic fan drive. Position the spring clamp.
(11) Connect the power steering filter hoses to the
filter. Install new hose clamps.
(12) Rotate the fan blades (by hand) and check for
interference at fan shroud.
(13) Refill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(14) Refill the power steering reservoir and bleed
air from system (Refer to 19 - STEERING/PUMP -
STANDARD PROCEDURE).
(15) Connect battery cable at battery.
(16) Start and warm engine. Check for leaks.
RADIATOR - 4.0L
DESCRIPTION
All vehicles are equipped with a cross flow type
radiator with plastic side tanks (Fig. 36).
Plastic tanks, while stronger than brass, are sub-
ject to damage by impact, such as from tools or
wrenches. Handle radiator with care.
REMOVAL
WARNING: DO 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 DRAIN-
ING.
Fig. 35 Radiator Alignment Dowels - Typical
1 - RADIATOR
2 - ALIGNMENT DOWEL
3 - RADIATOR LOWER ISOLATOR
4 - RADIATOR LOWER CROSSMEMBER
7 - 44 ENGINEWJ
RADIATOR - 4.7L (Continued)

INSPECTION
The radiator cooling fins should be checked for
damage or deterioration. Inspect cooling fins to make
sure they are not bent or crushed, these areas result
in reduced heat exchange causing the cooling system
to operate at higher temperatures. Inspect the plastic
end tanks for cracks, damage or leaks.
Inspect the radiator neck for damage or distortion.
INSTALLATION
CAUTION: Before installing the radiator or A/C con-
denser, be sure the radiator-to-body and radiator-to-
A/C condenser rubber air seals (Fig. 39) are
properly fastened to their original positions. These
are used at the top, bottom and sides of the radia-
tor and A/C condenser. To prevent overheating,
these seals must be installed to their original posi-
tions.
(1) Equipped with air conditioning: Gently lower
the radiator into the vehicle. Guide the two radiator
alignment dowels through the holes in the rubber air
seals first and then through the A/C support brackets
(Fig. 40). Continue to guide the alignment dowels
into the rubber grommets located in lower radiator
crossmember. The holes in the L-shaped brackets
(located on bottom of A/C condenser) must be posi-
tioned between bottom of rubber air seals and top of
rubber grommets.
(2) Connect the radiator upper and lower hoses
and hose clamps to radiator (Fig. 41).
CAUTION: The tangs on the hose clamps must be
positioned straight down.
(3) Install coolant reserve/overflow tank hose at
radiator (Fig. 41).
(4) Connect both transmission cooler lines at the
radiator (Fig. 41).
(5) Install both radiator mounting bolts (Fig. 41).
(6) Install air inlet duct at grill.
(7) Attach electric fan harness to shroud, then con-
nect harness to connector (Fig. 41).
(8) Install the grill (Refer to 23 - BODY/EXTERI-
OR/GRILLE - INSTALLATION).
(9) Install the fan/viscous fan drive assembly to
the water pump.
(10) Rotate the fan blades (by hand) and check for
interference at fan shroud.
(11) Be sure of at least 25 mm (1.0 inch) between
tips of fan blades and fan shroud.
(12) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(13) Connect battery cable at battery.
(14) Start and warm engine. Check for leaks.
RADIATOR FAN MOTOR
DIAGNOSIS AND TESTINGÐELECTRIC
COOLING FAN
The powertrain control module (PCM) will enter a
diagnostic trouble code (DTC) in memory if it detects
a problem in the auxiliary cooling fan relay or circuit.
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
If the electric cooling fan is inoperative, check the
15A fuse in the junction block and the 40A fuse in
the Power Distribution Center (PDC) with a 12 volt
test lamp or DVOM. Refer to the inside of the PDC
cover for the exact location of the fuse. If fuses are
okay, refer to ELECTRICAL for cooling fan and relay
circuit schematic.
WATER PUMP - 4.7L
DESCRIPTION
DESCRIPTIONÐWATER PUMP
A centrifugal water pump 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 lubri-
cated 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 a non serviceable integral pulley (Fig.
42).
DESCRIPTIONÐWATER PUMP BYPASS
The 4.7L engine uses an internal water/coolant
bypass system. The design uses galleries in the tim-
ing 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 (Fig. 43)
to control flow through the bypass gallery.
OPERATION
OPERATIONÐWATER PUMP
A centrifugal water pump circulates coolant
through the water jackets, passages, intake manifold,
WJENGINE 7 - 47
RADIATOR - 4.0L (Continued)

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.
OPERATIONÐWATER PUMP BYPASS
When the thermostat is in the closed position the
bypass gallery is not obstructed allowing 100% flow.
When the thermostat is in the open position the stub
shaft enters the bypass gallery obstructing bypass
coolant flow by 50%. This design allows the coolant
to reach operating temperature quickly when cold,
while adding extra cooling during normal tempera-
ture operation.
DIAGNOSIS AND TESTINGÐWATER PUMP
LOOSE IMPELLER - 4.0L and 4.7L
NOTE: Due to the design of the 4.0L and 4.7L
engine water pumps, testing the pump for a loose
impeller must be done by verifying coolant flow in
the radiator. To accomplish this refer to the follow-
ing procedure.
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.(1) Drain coolant until the first row of cores is vis-
ible in the radiator (Refer to 7 - COOLING - STAN-
DARD PROCEDURE) 4.7L Engine or (Refer to 7 -
COOLING - STANDARD PROCEDURE) 4.0L
Engine.
(2) Leaving the radiator cap off, start the engine.
Run engine until thermostat opens.
(3) While looking into the radiator through the
radiator fill neck, raise engine rpm to 2000 RPM.
Observe the flow of coolant from the first row of
cores.
(4) If there is no flow or very little flow visable,
replace the water pump.
INSPECTING FOR INLET RESTRICTIONS
Inadequate heater performance may be caused by
a metal casting restriction in the heater hose inlet.
DO NOT WASTE reusable coolant. If solution is
clean, drain the coolant into a clean container for
reuse.
Fig. 42 Water Pump and Timing Chain Cover
1 - INTEGRAL WATER PUMP PULLEY
2 - TIMING CHAIN COVER
3 - THERMOSTAT HOUSING
4 - HEATER HOSE FITTINGS
5 - WATER PUMP
Fig. 43 Water/Coolant Bypass Flow and Thermostat
1 - FROM HEATER
2 - FROM RADIATOR
3 - TO WATER PUMP
4 - ENGINE BYPASS
5 - THERMOSTAT
7 - 48 ENGINEWJ
WATER PUMP - 4.7L (Continued)

WARNING: DO NOT LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM THE COOL-
ANT CAN OCCUR.
(1) Drain sufficient coolant from the radiator to
decrease the level below the heater hose inlet. On
4.7L engines this requires complete draining.
(2) Remove the heater hose.
(3) Inspect the inlet for metal casting flash or
other restrictions.
NOTE: On 4.0L engines remove the pump from the
engine before removing restriction to prevent con-
tamination of the coolant with debris. . On 4.7L
engine remove the fitting from the timing chain
cover, If the restriction is in the timing chain cover,
remove the timing chain cover.
REMOVAL
The water pump on 4.7L engines is bolted directly
to the engine timing chain case/cover.
A gasket is used as a seal between the water pump
and timing chain case/cover.
The water pump can be removed without discharg-
ing the air conditioning system (if equipped).
(1) Disconnect negative battery cable from battery.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE). 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, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094). SNAP-ON CLAMP TOOL (NUMBER HPC-20)
MAY BE USED FOR LARGER CLAMPS. ALWAYS
WEAR SAFETY GLASSES WHEN SERVICING CON-
STANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with matching number or letter.
(3) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Remove lower radiator hose clamp and remove
lower hose at water pump.
(5) 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 dam-
aged resulting in leaks.
(6) Remove water pump and gasket. Discard gas-
ket.
CLEANING
Clean the gasket mating surface. Use caution not
to damage the gasket sealing surface.
INSPECTION
Inspect the water pump assembly for cracks in the
housing, Water leaks from shaft seal, Loose or rough
turning bearing or Impeller rubbing either the pump
body or timing chain case/cover.
INSTALLATION
(1) Clean gasket mating surfaces.
(2) Using a new gasket, position water pump and
install mounting bolts as shown. (Fig. 44). Tighten
water pump mounting bolts to 54 N´m (40 ft. lbs.)
torque.
(3) Spin water pump to be sure that pump impel-
ler does not rub against timing chain case/cover.
(4) Connect radiator lower hose to water pump.
(5) Install accessory drive belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
Fig. 44 Water Pump Installation
1 - WATER PUMP
2 - TIMING CHAIN COVER
WJENGINE 7 - 49
WATER PUMP - 4.7L (Continued)

CAUTION: When installing the serpentine accessory
drive belt, belt must be routed correctly. If not,
engine may overheat due to water pump rotating in
wrong direction.
(6) Refill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(7) Connect negative battery cable.
(8) Start and warm the engine. Check for leaks.
WATER PUMP - 4.0L
DESCRIPTION
CAUTION: All 4.0L 6-cylinder engines are equipped
with a reverse (counterclockwise) rotating water
pump and thermal viscous fan drive assembly.
REVERSE is stamped or imprinted on the cover of
the viscous fan drive and inner side of the fan. The
letter R is stamped into the back of the water pump
impeller. Engines from previous model years,
depending upon application, may have been
equipped with a forward (clockwise) rotating water
pump. Installation of the wrong water pump or vis-
cous fan drive will cause engine over heating.
A centrifugal water pump 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 lubri-
cated by the antifreeze in the coolant mixture. No
additional lubrication is necessary (Fig. 45).
DIAGNOSIS AND TESTINGÐWATER PUMP
LOOSE IMPELLER - 4.0L and 4.7L
NOTE: Due to the design of the 4.0L and 4.7L
engine water pumps, testing the pump for a loose
impeller must be done by verifying coolant flow in
the radiator. To accomplish this refer to the follow-
ing procedure.
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
(1) Drain coolant until the first row of cores is vis-
ible in the radiator (Refer to 7 - COOLING - STAN-
DARD PROCEDURE) 4.7L Engine or (Refer to 7 -
COOLING - STANDARD PROCEDURE) 4.0L
Engine.(2) Leaving the radiator cap off, start the engine.
Run engine until thermostat opens.
(3) While looking into the radiator through the
radiator fill neck, raise engine rpm to 2000 RPM.
Observe the flow of coolant from the first row of
cores.
(4) If there is no flow or very little flow visable,
replace the water pump.
INSPECTING FOR INLET RESTRICTIONS
Inadequate heater performance may be caused by
a metal casting restriction in the heater hose inlet.
DO NOT WASTE reusable coolant. If solution is
clean, drain the coolant into a clean container for
reuse.
WARNING: DO NOT LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM THE COOL-
ANT CAN OCCUR.
(1) Drain sufficient coolant from the radiator to
decrease the level below the heater hose inlet. On
4.7L engines this requires complete draining.
(2) Remove the heater hose.
(3) Inspect the inlet for metal casting flash or
other restrictions.
Fig. 45 Water Pump
1 - HEATER HOSE FITTING BORE
2 - WATER PUMP
3 - WATER PUMP HUB
7 - 50 ENGINEWJ
WATER PUMP - 4.7L (Continued)

NOTE: On 4.0L engines remove the pump from the
engine before removing restriction to prevent con-
tamination of the coolant with debris. . On 4.7L
engine remove the fitting from the timing chain
cover, If the restriction is in the timing chain cover,
remove the timing chain cover.
REMOVAL
CAUTION: If the water pump is replaced because of
mechanical damage, the fan blades and viscous fan
drive should also be inspected. These components
could have been damaged due to excessive vibra-
tion.
The water pump impeller is pressed on the rear of
the pump shaft and bearing assembly. The water
pump is serviced only as a complete assembly.
NOTE: The water pump can be replaced without
discharging the A/C system.
WARNING: DO NOT REMOVE THE BLOCK DRAIN
PLUG(S) OR LOOSEN RADIATOR DRAINCOCK
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM 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 7 - COOL-
ING - STANDARD PROCEDURE).
(3) The thermal viscous fan drive is attached
(threaded) to the water pump hub shaft. Remove fan/
viscous fan drive assembly from water pump by turn-
ing mounting nut counterclockwise as viewed from
front. Threads on viscous fan drive areRIGHT
HANDDo not attempt to remove fan/viscous fan
drive assembly from vehicle at this time.
(4) If water pump is being replaced, do not unbolt
fan blade assembly from thermal viscous fan drive.
(5) Remove fan shroud-to-radiator nuts (Fig. 46).
Do not attempt to remove fan shroud at this time.
(6) Remove fan shroud and fan blade/viscous fan
drive assembly from vehicle as a complete unit.
(7) After removing fan blade/viscous fan drive
assembly,do notplace 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.
Loosen but do not remove the water pump pulley
mounting bolts.Remove accessory drive belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - REMOV-
AL).
Remove the water pump pulley.
(8) Remove the idler pulley (located over the water
pump).
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, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094) (Fig. 47) SNAP-ON CLAMP TOOL (NUMBER
HPC-20) MAY BE USED FOR LARGER CLAMPS.
ALWAYS WEAR SAFETY GLASSES WHEN SERVIC-
ING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps (Fig. 48). If
replacement is necessary, use only an original
equipment clamp with matching number or letter.
(9) Remove lower radiator hose from water pump.
Remove heater hose from water pump fitting.
(10) Remove the five pump mounting bolts (Fig.
49) and remove pump from vehicle. Discard old gas-
ket. Note that one of the five bolts is longer than the
other bolts.
(11) If pump is to be replaced, the heater hose fit-
ting must be removed. Note position of fitting before
removal.
Fig. 46 Fan Shroud Mounting
1 - SHROUD FASTENERS
2 - DRAIN COCK
3 - RADIATOR FAN SHROUD
4 - SHROUD FASTENERS
WJENGINE 7 - 51
WATER PUMP - 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

²Front Check Valve- The front washer system
check valve is integral to the wye fitting located in
the washer plumbing between the cowl plenum
washer hose and the front washer nozzles, and is
concealed beneath the cowl plenum cover/grille panel
at the base of the windshield.
²Front Washer Nozzle- Two fluidic front
washer nozzles are secured with integral snap fea-
tures to dedicated openings in the cowl plenum cover/
grille panel located near the base of the windshield.
²Front Washer Plumbing- The plumbing for
the front washer system consists of rubber hoses and
molded plastic fittings. The plumbing is routed along
the left side of the engine compartment from the
washer reservoir, and through the dash panel into
the cowl plenum to the front washer nozzle fittings
beneath the cowl plenum cover/grille panel.
²Front Washer Pump/Motor- The front washer
pump/motor unit is located in a dedicated hole on the
lower outboard side of the washer reservoir, behind
the inner fender liner ahead of the left front wheel.
The front washer pump is located ahead of and below
the rear washer pump.
²Front Wiper Arm- The two front wiper arms
are secured with nuts to the threaded studs on the
ends of the two wiper pivot shafts, which extend
through the cowl plenum cover/grille panel located
near the base of the windshield.
²Front Wiper Blade- The two front wiper
blades are secured to the two front wiper arms with
an integral latch, and are parked on the glass near
the bottom of the windshield when the front wiper
system is not in operation.
²Front Wiper Module- The front wiper pivot
shafts are the only visible components of the front
wiper module. The remainder of the module is con-
cealed within the cowl plenum beneath the cowl ple-
num cover/grille panel. The front wiper module
includes the module bracket, four rubber-isolated
wiper module mounts, the front wiper motor, the
wiper motor crank arm, the two wiper drive links,
and the two front wiper pivots.
²Rain Sensor Module- Models equipped with
the optional automatic wiper feature have a Rain
Sensor Module (RSM) located behind a trim cover on
a bracket bonded to the inside surface of the wind-
shield glass, just above the inside rear view mirror
mounting button.
²Right Multi-Function Switch- The right
(wiper) multi-function switch is secured to the right
side of the multi-function switch mounting housing
near the top of the steering column, just below the
steering wheel. Only the control stalk for the right
multi-function switch is visible, while the remainder
of the switch is concealed beneath the steering col-
umn shrouds. The right multi-function switch con-tains all of the switches and control circuitry for both
the front and rear wiper and washer systems.
²Washer Fluid Level Switch- The washer fluid
level switch is located in a dedicated hole near the
center of the forward surface of the washer reservoir,
behind the left front wheel house splash shield.
²Washer Reservoir- The washer reservoir is
concealed between the left inner fender shield and
the left outer fender panel, behind the inner fender
liner and ahead of the left front wheel. The washer
reservoir filler neck is the only visible portion of the
reservoir, and it is accessed from the left front corner
of the engine compartment.
²Wiper High-Low Relay- The wiper high-low
relay is an International Standards Organization
(ISO) micro relay located in the Power Distribution
Center (PDC) in the engine compartment near the
battery.
²Wiper On-Off Relay- The wiper on-off relay is
an International Standards Organization (ISO) micro
relay located in the Power Distribution Center (PDC)
in the engine compartment near the battery.
Hard wired circuitry connects the front wiper and
washer system components to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the front wiper and
washer system components through the use of a com-
bination of soldered splices, splice block connectors,
and many different types of wire harness terminal
connectors and insulators. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.
OPERATING MODES
The components of the front wiper and washer sys-
tem are designed to work in concert to provide the
following operating modes:
²Automatic Wiper- In models equipped with
the optional automatic wiper feature, the internal
circuitry of both the right (wiper) multi-function
switch, the rain sensor module, and the BCM work
in concert to provide an automatic wiper mode with
five sensitivity selections. The BCM tells the Rain
Sensor Module (RSM) when the automatic wiper
mode is selected and the manually selected sensitiv-
ity level, then the rain sensor module tells the BCM
each time enough water droplets have accumulated
within the wipe pattern on the windshield to require
front wiper operation. The BCM then automatically
WJFRONT WIPERS/WASHERS 8R - 3
FRONT WIPERS/WASHERS (Continued)

REMOVAL
REMOVAL - CAMSHAFT BEARINGS.......31
REMOVAL - CAMSHAFT................31
INSPECTION
INSPECTION - CAMSHAFT BEARINGS.....31
INSPECTION - CAMSHAFT..............31
INSTALLATION
INSTALLATION - CAMSHAFT BEARINGS . . . 32
INSTALLATION - CAMSHAFT............32
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - FITTING
CONNECTING ROD BEARINGS..........33
CRANKSHAFT
DESCRIPTION.........................35
CRANKSHAFT MAIN BEARINGS
STANDARD PROCEDURE - FITTING
CRANKSHAFT MAIN BEARINGS..........36
REMOVAL.............................39
INSPECTION..........................40
INSTALLATION.........................40
CRANKSHAFT OIL SEAL - FRONT
REMOVAL.............................41
INSTALLATION.........................41
CRANKSHAFT OIL SEAL - REAR
REMOVAL.............................42
INSTALLATION.........................42
HYDRAULIC LIFTERS
DESCRIPTION.........................43
REMOVAL.............................43
CLEANING............................43
INSPECTION..........................43
INSTALLATION.........................43
PISTON & CONNECTING ROD
DESCRIPTION.........................44
STANDARD PROCEDURE - PISTON FITTING . 44
REMOVAL.............................45
INSTALLATION.........................46
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING.............................47
VIBRATION DAMPER
REMOVAL.............................49
INSTALLATION.........................49STRUCTURAL SUPPORT
REMOVAL.............................49
INSTALLATION.........................50
LUBRICATION
DESCRIPTION.........................50
OPERATION...........................50
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE OIL
PRESSURE..........................51
DIAGNOSIS AND TESTING - ENGINE OIL
LEAK...............................51
OIL
STANDARD PROCEDURE - ENGINE OIL
SERVICE............................53
OIL FILTER
REMOVAL.............................53
INSTALLATION.........................54
OIL PAN
DESCRIPTION.........................54
REMOVAL.............................54
INSTALLATION.........................55
ENGINE OIL PRESSURE SENSOR
DESCRIPTION.........................56
OPERATION...........................56
OIL PUMP
REMOVAL.............................56
INSTALLATION.........................57
INTAKE MANIFOLD
DESCRIPTION.........................57
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKAGE..................57
REMOVAL.............................57
INSTALLATION.........................57
EXHAUST MANIFOLD
DESCRIPTION.........................58
REMOVAL.............................58
INSTALLATION.........................58
TIMING BELT / CHAIN COVER(S)
REMOVAL.............................58
INSTALLATION.........................58
TIMING BELT/CHAIN AND SPROCKETS
REMOVAL.............................60
INSTALLATION.........................60
ENGINE - 4.0L
DESCRIPTION
The 4.0 Liter (242 CID) six-cylinder engine is an
In-line, lightweight, overhead valve engine. This
engine is designed for unleaded fuel.
The engine cylinder head has dual quench-type
combustion chambers that create turbulence and fast
burning of the air/fuel mixture. This results in better
fuel economy.
The cylinders are numbered 1 through 6 from front
to rear. The firing order is 1-5-3-6-2-4 (Fig. 1).The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within seven main bearings. The camshaft rotates
within four bearings.
The engine Build Date Code is located on a
machined surface on the right side of the cylinder
block between the No.2 and No.3 cylinders (Fig. 2).
The digits of the code identify:
²1st DigitÐThe year (8 = 1998).
²2nd & 3rd DigitsÐThe month (01 - 12).
²4th & 5th DigitsÐThe engine type/fuel system/
compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1
compression ratio engine with a multi-point fuel
injection system).
9 - 2 ENGINE - 4.0LWJ

DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
ENGINE PERFORMANCE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL NOT CRANK 1. Weak or dead battery 1. Charge/Replace Battery. (Refer to
8 - ELECTRICAL/BATTERY
SYSTEM/BATTERY - STANDARD
PROCEDURE), for correct
procedures. Check charging system.
(Refer to 8 - ELECTRICAL/
CHARGING - DIAGNOSIS AND
TESTING), for correct procedures.
2. Corroded or loose battery
connections2. Clean/tighten suspect battery/
starter connections
3. Faulty starter or related circuit(s) 3. Check starting system. (Refer to 8
- ELECTRICAL/STARTING -
DIAGNOSIS AND TESTING), for
correct diagnostics/procedures
4. Siezed accessory drive
component4. Remove accessory drive belt and
attempt to start engine. If engine
starts, repair/replace siezed
component.
5. Engine internal mechanical failure
or hydro-static lock5. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING), for
correct diagnostics/procedures
ENGINE CRANKS BUT WILL
NOT START1. No spark 1. Check for spark. (Refer to 8 -
ELECTRICAL/IGNITION CONTROL -
SPECIFICATIONS), for correct
procedures.
2. No fuel 2. Perform fuel pressure test (Refer
to 14 - FUEL SYSTEM/FUEL
DELIVERY/FUEL PUMP -
DIAGNOSIS AND TESTING), and if
necessary, inspect fuel injector(s) and
driver circuits. (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/FUEL
INJECTOR - DIAGNOSIS AND
TESTING), for correct procedures.
3. Low or no engine compression 3. Perform cylinder compression
pressure test. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
ENGINE LOSS OF POWER 1. Worn or burned distributor rotor 1. Install new distributor rotor
2. Worn camshaft position sensor
shaft2. Remove and repair camshaft
position sensor.(Refer to 8 -
ELECTRICAL/IGNITION CONTROL/
CAMSHAFT POSITION SENSOR -
REMOVAL).
9 - 4 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)