Valve cover JEEP GRAND CHEROKEE 2002 WJ / 2.G Owner's Manual

INSPECTION
Inspect the pivot surface area of each rocker arm.
Replace any that are scuffed, pitted, cracked or
excessively worn.
Inspect the valve stem tip contact surface of each
rocker arm and replace any rocker arm that is deeply
pitted.
Inspect each push rod end for excessive wear and
replace as required. If any push rod is excessively
worn because of lack of oil, replace it and inspect the
corresponding hydraulic tappet for excessive wear.
Inspect the push rods for straightness by rolling
them on a flat surface or by shining a light between
the push rod and the flat surface.
A wear pattern along the length of the push rod is
not normal. Inspect the engine cylinder head for
obstruction if this condition exists.
INSTALLATION
NOTE: This procedure can be done with the engine
in or out of the vehicle.
(1) Lubricate the ball ends of the push rods with
MopartEngine Oil Supplement, or equivalent and
install push rods in their original locations. Ensurethat the bottom end of each push rod is centered in
the tappet plunger cap seat.
(2) Using MopartEngine Oil Supplement, or
equivalent, lubricate the area of the rocker arm that
the pivot contacts. Install rocker arms, pivots and
bridge above each cylinder in their originally position
(Fig. 23).
(3) Loosely install the capscrews through each
bridge.
(4) At each bridge, tighten the capscrews alter-
nately, one turn at a time, to avoid damaging the
bridge. Tighten the capscrews to 28 N´m (21 ft. lbs.)
torque.
(5) Install the engine cylinder head cover (Refer to
9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
VALVE STEM SEALS
DESCRIPTION
The valve stem seals (Fig. 24) are made of rubber
and incorporate a garter spring to maintain consis-
tent lubrication control.
Fig. 22 Rocker Arm
1 - CAPSCREWS
2 - BRIDGE
3 - PIVOT ASSEMBLY
4 - PUSH RODS
5 - ROCKER ARMS
Fig. 23 Rocker Arm
1 - CAPSCREWS
2 - BRIDGE
3 - PIVOT ASSEMBLY
4 - PUSH RODS
5 - ROCKER ARMS
WJENGINE - 4.0L 9 - 27
ROCKER ARM / ADJUSTER ASSEMBLY (Continued)

VALVE SPRINGS
DESCRIPTION
The valve springs (Fig. 25) are made of high
strength silicon chrome spring steel. The springs are
common for both intake and exhaust valves.
STANDARD PROCEDURE - VALVE SPRING
TENSION TEST
Clean all carbon deposits from the combustion
chambers, valve ports, valve stems, valve stem
guides and head.
Use a universal Valve Spring Tester and a torque
wrench to test each valve spring for the specified ten-
sion value (Fig. 26).
Replace valve springs that are not within specifica-
tions.
REMOVAL
NOTE: This procedure can be done with the engine
cylinder head installed on the block.
Inspect the valve stems, especially the grooves. An
Arkansas smooth stone should be used to remove
nicks and high spots.Each valve spring is held in place by a retainer
and a set of conical valve locks. The locks can be
removed only by compressing the valve spring.
(1) Remove the engine cylinder head cover (Refer
to 9 - ENGINE/CYLINDER HEAD/CYLINDER
HEAD COVER(S) - REMOVAL).
Fig. 24 Valve
1 - VALVE LOCKS (3±BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
Fig. 25 VALVE AND KEEPER CONFIGURATION 4.0L
1 - VALVE LOCKS (3±BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
Fig. 26 Valve Spring Tester
1 - TORQUE WRENCH
2 - VALVE SPRING TESTER
9 - 28 ENGINE - 4.0LWJ
VALVE STEM SEALS (Continued)

(2) Remove cap screws, bridge and pivot assem-
blies and rocker arms (Refer to 9 - ENGINE/CYLIN-
DER HEAD/ROCKER ARM / ADJUSTER ASSY -
REMOVAL) for access to each valve spring to be
removed.
(3) Remove push rods.Retain the push rods,
bridges, pivots and rocker arms in the same
order and position as removed.
(4) Inspect the springs and retainer for cracks and
possible signs of weakening.
(5) Remove the spark plug(s) adjacent to the cylin-
der(s) below the valve springs to be removed.
(6) Connect an air hose to the adapter and apply
air pressure slowly. Maintain at least 621 kPa (90
psi) of air pressure in the cylinder to hold the valves
against their seats. For vehicles equipped with an air
conditioner, use a flexible air adaptor when servicing
the No.1 cylinder.
(7) Tap the retainer or tip with a rawhide hammer
to loosen the lock from the retainer. Use Valve Spring
Compressor Tool MD-998772A to compress the spring
and remove the locks (Fig. 27).
(8) Remove valve spring and retainer (Fig. 27).
(9) Remove valve stem oil seals (Fig. 27). Note the
valve seals are different for intake and exhaust
valves. The top of each seal is marked either INT
(intake/black in color) or EXH (exhaust/brown in
color). DO NOT mix the seals.
INSTALLATION
NOTE: This procedure can be done with the engine
cylinder head installed on the block.
CAUTION: Install oil seals carefully to prevent dam-
age from the sharp edges of the valve spring lock
grove.
(1) Lightly push the valve seal over the valve stem
and valve guide boss. Be sure the seal is completely
seated on the valve guide boss.
(2) Install valve spring and retainer (Fig. 28).
(3) Compress the valve spring with Valve Spring
Compressor Tool MD-998772A and insert the valve
locks. Release the spring tension and remove the
tool. Tap the spring from side-to-side to ensure that
the spring is seated properly on the engine cylinder
head.(4) Release air pressure and disconnect the air
hose. Remove the adaptor from the spark plug hole
and install the spark plug.
(5) Repeat the procedures for each remaining valve
spring to be removed.
(6) Install the push rods. Ensure the bottom end of
each rod is centered in the plunger cap seat of the
hydraulic valve tappet.
(7) Install the rocker arms, pivots and bridge
(Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - INSTALLATION) at their
original location.
(8) Install the engine cylinder head cover (Refer to
9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
Fig. 27 Valve and Valve Components
1 - VALVE LOCKS (3±BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
WJENGINE - 4.0L 9 - 29
VALVE SPRINGS (Continued)

REMOVAL
REMOVAL - CAMSHAFT BEARINGS
The camshaft rotates within four steel-shelled,
babbitt-lined bearings that are pressed into the cyl-
inder block and then line reamed. The camshaft
bearing bores and bearing diameters are not the
same size. They are stepped down in 0.254 mm
(0.010 inch) increments from the front bearing (larg-
est) to the rear bearing (smallest). This permits eas-
ier removal and installation of the camshaft. The
camshaft bearings are pressure lubricated. Camshaft
end play is maintained by the thrust plate.
(1) Remove the camshaft (Refer to 9 - ENGINE/
ENGINE BLOCK/CAMSHAFT & BEARINGS (IN
BLOCK) - REMOVAL).
NOTE: It is not advisable to attempt to replace cam-
shaft bearings unless special removal and installa-
tion tools are available, such as recommended tool
8544 Camshaft Bushing Remover Installer.
(2) Using Special tool 8544 Camshaft Bushing
Remover Installer, remove the camshaft bearings.
REMOVAL - CAMSHAFT
WARNING: THE COOLANT IN A RECENTLY OPER-
ATED ENGINE IS HOT AND PRESSURIZED.RELEASE THE PRESSURE BEFORE REMOVING
THE DRAIN COCK, CAP AND DRAIN PLUGS.
(1) Disconnect negative cable from battery.
(2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(3) Remove the radiator (Refer to 7 - COOLING/
ENGINE/RADIATOR - REMOVAL) and condenser
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/A/C CONDENSER - REMOVAL), if
equipped with A/C.
(4) Remove the engine cylinder head cover (Refer
to 9 - ENGINE/CYLINDER HEAD/CYLINDER
HEAD COVER(S) - REMOVAL).
(5) Remove the rocker arms, bridges and pivots
(Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - REMOVAL).
(6) Remove the push rods.
(7) Remove the engine cylinder head and gasket
(Refer to 9 - ENGINE/CYLINDER HEAD - REMOV-
AL).
(8) Remove the hydraulic valve tappets from the
engine cylinder block (Refer to 9 - ENGINE/ENGINE
BLOCK/HYDRAULIC LIFTERS (CAM IN BLOCK) -
REMOVAL).
(9) Remove the vibration damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(10) Remove the timing case cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(11) Rotate the crankshaft until the crankshaft
sprocket timing mark is aligned on centerline with
the camshaft sprocket timing mark (Fig. 32).
(12) Remove the timing chain and sprockets (Refer
to 9 - ENGINE/VALVE TIMING/TIMING BELT/
CHAIN AND SPROCKETS - REMOVAL).
(13) Remove the front bumper and/or grille, as
required.
(14) Remove the two thrust plate retaining screws,
thrust plate and camshaft (Fig. 31).
INSPECTION
INSPECTION - CAMSHAFT BEARINGS
(1) Inspect the bearing journals for uneven wear
pattern or finish.
(2) Inspect the bearings for wear.
INSPECTION - CAMSHAFT
(1) Inspect the cam lobes for wear.
(2) Inspect the camshaft position sensor drive gear
for wear.
(3) If the camshaft appears to have been rubbing
against the thrust washer, examine the oil pressure
Fig. 30 CamshaftÐTypical
1 - CAMSHAFT
2 - LOBES
3 - BEARING JOURNAL
WJENGINE - 4.0L 9 - 31
CAMSHAFT & BEARINGS (Continued)

relief holes in the rear cam journal. The oil pressure
relief holes must be free of debris.
INSTALLATION
INSTALLATION - CAMSHAFT BEARINGS
CAUTION: Make sure outside diameter of number 1
bearing is clean. Make sure that the bearing is
properly installed in the engine block, align the oil
hole in the bearing with the oil gallery in the bear-
ing bore. Failure to do so will cause inadequate oil
supply for the sprockets and timing chain.
(1) Using recommended special tool 8544 Cam-
shaft Bearing Remover/Installer, install new cam-
shaft bearings.
INSTALLATION - CAMSHAFT
(1) Lubricate the camshaft with MopartEngine
Oil Supplement, or equivalent.
(2) Carefully install the camshaft to prevent dam-
age to the camshaft bearings.
(3) Position thrust plate and install retaining
screws. Tighten screws to 24 N´m (18 ft. lbs.).
(4) Lubricate the camshaft with Mopartengine oil
supplement, or equivalent.
(5) Install the camshaft sprocket, crankshaft
sprocket and timing chain (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION).
(6) Tighten the camshaft sprocket bolt and washer
to 68 N´m (50 ft. lbs.).
(7) To verify correct installation of the timing
chain, turn the crankshaft two full revolutions then
position the camshaft sprocket timing mark as shown
in (Fig. 33).
(8) Install the timing case cover with a replace-
ment oil seal (Fig. 34). (Refer to 9 - ENGINE/VALVE
TIMING/TIMING BELT / CHAIN COVER(S) -
INSTALLATION).
(9) Install the vibration damper (Fig. 34) (Refer to
9 - ENGINE/ENGINE BLOCK/VIBRATION
DAMPER - INSTALLATION).
(10) Install the hydraulic valve tappets (Refer to 9
- ENGINE/ENGINE BLOCK/HYDRAULIC LIFTERS
(CAM IN BLOCK) - INSTALLATION).
(11) Install the cylinder head gasket with the
numbers facing up.
(12) Install the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - INSTALLATION).
(13) Install the push rods.
(14) Install the rocker arms and pivot and bridge
assemblies (Refer to 9 - ENGINE/CYLINDER HEAD/
ROCKER ARM / ADJUSTER ASSY - INSTALLA-
TION).
(15) Install the engine cylinder head cover (Refer
to 9 - ENGINE/CYLINDER HEAD/CYLINDER
HEAD COVER(S) - INSTALLATION).
Fig. 31 Camshaft Removal
1 - CAMSHAFT
2 - CRANKSHAFT
Fig. 32 Crankshaft / Camshaft Sprocket Timing Mark
Alignment
1 - CAMSHAFT SPROCKET
2 - TIMING MARKS
3 - CRANKSHAFT SPROCKET
9 - 32 ENGINE - 4.0LWJ
CAMSHAFT & BEARINGS (Continued)

(16) Install the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
NOTE: During installation, lubricate the hydraulic
valve tappets and all valve components with
MoparTEngine Oil Supplement, or equivalent. TheMoparTEngine Oil Supplement, or equivalent must
remain with the engine oil for at least 1609 km
(1,000 miles). The oil supplement need not be
drained until the next scheduled oil change.
(17) Install the radiator (Refer to 7 - COOLING/
ENGINE/RADIATOR - INSTALLATION).
(18) Check the ignition timing and adjust as nec-
essary.
(19) Install the grille and bumper, if removed.
(20) Connect negative cable to battery.
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - FITTING
CONNECTING ROD BEARINGS
Inspect the connecting rod bearings for scoring and
bent alignment tabs (Fig. 35) (Fig. 36). Check the
bearings for normal wear patterns, scoring, grooving,
fatigue and pitting (Fig. 37). Replace any bearing
that shows abnormal wear.
Inspect the connecting rod journals for signs of
scoring, nicks and burrs.
Misaligned or bent connecting rods can cause
abnormal wear on pistons, piston rings, cylinder
walls, connecting rod bearings and crankshaft con-
necting rod journals. If wear patterns or damage to
any of these components indicate the probability of a
misaligned connecting rod, inspect it for correct rod
alignment. Replace misaligned, bent or twisted con-
necting rods.
Fig. 33 Crankshaft / Camshaft Chain Drive
InstallationÐTypical
1 - CAMSHAFT SPROCKET
2 - TIMING MARKS
3 - CRANKSHAFT SPROCKET
Fig. 34 Timing Case Cover Components
1 - TIMING CASE COVER
2 - OIL SLINGER
3 - CRANKSHAFT OIL SEAL
4 - VIBRATION DAMPER PULLEY
Fig. 35 Connecting Rod Bearing Inspection
1 - UPPER BEARING HALF
2 - MATING EDGES
3 - GROOVES CAUSED BY ROD BOLTS SCRATCHING
JOURNAL DURING INSTALLATION
4 - WEAR PATTERN - ALWAYS GREATER ON UPPER BEARING
5 - LOWER BEARING HALF
WJENGINE - 4.0L 9 - 33
CAMSHAFT & BEARINGS (Continued)

It is not necessary to charge the tappets with
engine oil. They will charge themselves within a very
short period of engine operation.
(1) Dip each tappet in MopartEngine Oil Supple-
ment, or equivalent.
(2) Use Hydraulic Valve Tappet Removal/Installa-
tion Tool to install each tappet in the same bore from
where it was originally removed.
(3) Install the cylinder head (Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
(4) Install the push rods in their original locations.
(5) Install the rocker arms and bridge and pivot
assemblies at their original locations. Loosely install
the capscrews at each bridge.
(6) Tighten the capscrews alternately, one turn at
a time, to avoid damaging the bridges. Tighten the
capscrews to 28 N´m (21 ft. lbs.) torque.
(7)
Pour the remaining MopartEngine Oil Supple-
ment, or equivalent over the entire valve actuating
assembly. The MopartEngine Oil Supplement, or equiv-
alent must remain with the engine oil for at least 1 609
km (1,000 miles). The oil supplement need not be
drained until the next scheduled oil change.
(8) Install the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
PISTON & CONNECTING ROD
DESCRIPTION
The pistons (Fig. 55) are made of a high strength
aluminum alloy, the piston skirts are coated with a
solid lubricant (Molykote) to reduce friction and pro-
vide scuff resistance. The connecting rods are made
of cast iron.
STANDARD PROCEDURE - PISTON FITTING
(1) To correctly select the proper size piston, a cyl-
inder bore gauge, capable of reading in 0.003 mm
(.0001 in.) INCREMENTS is required. If a bore
gauge is not available, do not use an inside microme-
ter.
(2) Measure the inside diameter of the cylinder
bore at a point 49.5 mm (1-15/16 inches) below top of
bore. Start perpendicular (across or at 90 degrees) to
the axis of the crankshaft at point A and then take
an additional bore reading 90 degrees to that at point
B (Fig. 57).
(3) The coated pistons will be serviced with the
piston pin and connecting rod pre-assembled.The
coated piston connecting rod assembly can be
used to service previous built engines and
MUST be replaced as complete sets.Tin coated
pistons should not be used as replacements for coated
pistons.
(4) The coating material is applied to the piston
after the final piston machining process. Measuring
the outside diameter of a coated piston will not pro-
vide accurate results (Fig. 56). Therefore measuring
the inside diameter of the cylinder bore with a dial
Bore Gauge isMANDATORY. To correctly select the
proper size piston, a cylinder bore gauge capable of
reading in 0.003 mm (.0001 in.) increments is
required.
(5) Piston installation into the cylinder bore
requires slightly more pressure than that required
for non-coated pistons. The bonded coating on the
piston will give the appearance of a line-to-line fit
with the cylinder bore.
Fig. 55 Piston and Connecting Rod Assembly
Fig. 56 Moly Coated Piston
1 - MOLY COATED
2 - MOLY COATED
9 - 44 ENGINE - 4.0LWJ
HYDRAULIC LIFTERS (Continued)

crankshaft is drilled internally to pass oil from the
main bearing journals (except number 4 main bear-
ing journal) to the connecting rod journals. Each con-
necting rod bearing cap has a small squirt hole, oil
passes through the squirt hole and is thrown off as
the rod rotates. This oil throwoff lubricates the cam-
shaft lobes, distributor drive gear, cylinder walls, and
piston pins.
The hydraulic valve tappets receive oil directly
from the main oil gallery. Oil is provided to the cam-
shaft bearing through galleries. The front camshaft
bearing journal passes oil through the camshaft
sprocket to the timing chain. Oil drains back to the
oil pan under the number one main bearing cap.
The oil supply for the rocker arms and bridged
pivot assemblies is provided by the hydraulic valve
tappets which pass oil through hollow push rods to a
hole in the corresponding rocker arm. Oil from the
rocker arm lubricates the valve train components,
then passes down through the push rod guide holes
in the cylinder head past the valve tappet area, and
returns to the oil pan (Fig. 73).
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE OIL
PRESSURE
(1) Disconnect connector and remove oil pressure
sending unit.
(2) Install Oil Pressure Line and Gauge Tool
C-3292 or equivalent. Start engine and record pres-
sure. (Refer to 9 - ENGINE - SPECIFICATIONS) for
the correct pressures.
DIAGNOSIS AND TESTING - ENGINE OIL LEAK
Begin with a thorough visual inspection of the
engine, particularly at the area of the suspected leak.
If an oil leak source is not readily identifiable, the
following steps should be followed:
(1) Do not clean or degrease the engine at this
time because some solvents may cause rubber to
swell, temporarily stopping the leak.
(2) Add an oil soluble dye (use as recommended by
manufacturer). Start the engine and let idle for
approximately 15 minutes. Check the oil dipstick to
make sure the dye is thoroughly mixed as indicated
with a bright yellow color under a black light.
(3) Using a black light, inspect the entire engine
for fluorescent dye, particularly at the suspected area
of oil leak. If the oil leak is found and identified,
repair per service manual instructions.
(4) If dye is not observed, drive the vehicle at var-
ious speeds for approximately 24km (15 miles), and
repeat inspection.If the oil leak source is not pos-itively identified at this time, proceed with the air
leak detection test method.
Air Leak Detection Test Method
(1) Disconnect the breather cap to air cleaner hose
at the breather cap end. Cap or plug breather cap
nipple.
(2) Remove the CCV valve from the cylinder head
cover. Cap or plug the CCV valve grommet.
(3) Attach an air hose with pressure gauge and
regulator to the dipstick tube.
CAUTION: Do not subject the engine assembly to
more than 20.6 kpa (3 PSI) of test pressure.
(4) Gradually apply air pressure from 1 psi to 2.5
psi maximum while applying soapy water at the sus-
pected source. Adjust the regulator to the suitable
test pressure that provide the best bubbles which
will pinpoint the leak source. If the oil leak is
detected and identified, repair per service informa-
tion procedures.
(5) If the leakage occurs at the rear oil seal area,
INSPECTION FOR REAR SEAL AREA LEAKS .
(6) If no leaks are detected, turn off the air supply
and remove the air hose and all plugs and caps.
Install the CCV valve and breather cap hose.
(7) Clean the oil off the suspect oil leak area using
a suitable solvent. Drive the vehicle at various
speeds approximately 24 km (15 miles). Inspect the
engine for signs of an oil leak by using a black light.
INSPECTION FOR REAR SEAL AREA LEAKS
Since it is sometimes difficult to determine the
source of an oil leak in the rear seal area of the
engine, a more involved inspection is necessary. The
following steps should be followed to help pinpoint
the source of the leak.
If the leakage occurs at the crankshaft rear oil seal
area:
(1) Disconnect the battery.
(2) Raise the vehicle.
(3) Remove torque converter or clutch housing
cover and inspect rear of block for evidence of oil.
Use a black light to check for the oil leak:
(a) Circular spray pattern generally indicates
seal leakage or crankshaft damage.
(b) Where leakage tends to run straight down,
possible causes are a porous block, distributor seal,
camshaft bore cup plugs oil galley pipe plugs, oil
filter runoff, and main bearing cap to cylinder
block mating surfaces.
(4) If no leaks are detected, pressurize the crank-
case as outlined in the, Inspection (Engine oil Leaks
in general)
CAUTION: Do not exceed 20.6 kPa (3 psi).
WJENGINE - 4.0L 9 - 51
LUBRICATION (Continued)

(3) Install intake manifold on the cylinder head
dowels.
(4) Install washer and fastener Numbers 1, 2, 4, 5,
8, 9, 10 and 11 (Fig. 84).
(5) Install washer and fastener Numbers 6 and 7
(Fig. 84).
(6) Tighten the fasteners in sequence and to the
specified torque (Fig. 84).
²Fastener Numbers 1 through 5ÐTighten to 33
N´m (24 ft. lbs.) torque.
²Fastener Numbers 6 and 7ÐTighten to 31 N´m
(23 ft. lbs.) torque.
²Fastener Numbers 8 through 11ÐTighten to 33
N´m (24 ft. lbs.) torque.
(7) Install the power steering pump to the intake
manifold.
(8) Install the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(9) Install the fuel system supply line to the fuel
rail assembly.
(10) Connect all electrical connections on the
intake manifold.
(11) Connect the vacuum hoses previously
removed.
(12) Install throttle cable, vehicle speed control
cable (if equipped).
(13) Install the transmission line pressure cable (if
equipped) (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - AW4/THROTTLE VALVE
CABLE - INSTALLATION).
(14) Install air cleaner assembly.
(15) Connect air inlet hose to the resonator assem-
bly.
(16) Raise the vehicle.
(17) Connect the exhaust pipes to the engine
exhaust manifolds. Tighten the bolts to 31 N´m (23
ft. lbs.)
(18) Lower the vehicle.(19) Connect the battery negative cable.
(20) Start the engine and check for leaks.
EXHAUST MANIFOLD
DESCRIPTION
The two exhaust manifolds (Fig. 85) are log style
and are made of high silicon molybdenum cast iron.
The exhaust manifolds share a common gasket with
the intake manifold. The exhaust manifolds also
incorporate ball flange outlets for improved sealing
and strain free connections.
REMOVAL
The intake and engine exhaust manifolds on the
4.0L engine must be removed together. The manifolds
use a common gasket at the cylinder head.
(Refer to 9 - ENGINE/MANIFOLDS/INTAKE
MANIFOLD - REMOVAL).
INSTALLATION
(1) The exhaust manifold and the intake manifold
must be installed together using a common gasket.
(2) (Refer to 9 - ENGINE/MANIFOLDS/INTAKE
MANIFOLD - INSTALLATION).
TIMING BELT / CHAIN
COVER(S)
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the vibration damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(3) Remove the fan, hub assembly and fan shroud
(Refer to 7 - COOLING/ENGINE/RADIATOR FAN -
REMOVAL).
(4) Remove the accessory drive brackets that are
attached to the timing case cover.
(5) Remove the A/C compressor (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/A/C
COMPRESSOR - REMOVAL) (if equipped) and gen-
erator bracket assembly from the engine cylinder
head and move to one side.
(6) Remove the oil pan-to-timing case cover bolts
and timing case cover-to-cylinder block bolts.
(7) Remove the timing case cover and gasket from
the engine.
(8) Pry the crankshaft oil seal from the front of the
timing case cover (Fig. 86).
INSTALLATION
Clean the timing case cover, oil pan and cylinder
block gasket surfaces.
Fig. 84 Intake and Exhaust Manifolds Installation
9 - 58 ENGINE - 4.0LWJ
INTAKE MANIFOLD (Continued)

TIMING BELT/CHAIN AND
SPROCKETS
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the fan and shroud (Refer to 7 -
COOLING/ENGINE/RADIATOR FAN - REMOVAL).
(3) Remove the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Remove the crankshaft vibration damper (Refer
to 9 - ENGINE/ENGINE BLOCK/VIBRATION
DAMPER - REMOVAL).
(5) Remove the timing case cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(6) Rotate crankshaft until the ª0º timing mark is
closest to and on the center line with camshaft
sprocket timing mark (Fig. 88).
(7) Remove the oil slinger from the crankshaft.
(8) Remove the camshaft sprocket bolt and washer
(Fig. 89).
(9) Remove the crankshaft sprocket, camshaft
sprocket and timing chain as an assembly.
(10) Installation of the timing chain with the tim-
ing marks on the crankshaft and camshaft sprockets
properly aligned ensures correct valve timing. A worn
or stretched timing chain will adversely affect valvetiming. If the timing chain deflects more than 12.7
mm (1/2 inch) replace it.
INSTALLATION
Assemble the timing chain, crankshaft sprocket
and camshaft sprocket with the timing marks
aligned (Fig. 88).
(1) Apply MopartSilicone Rubber Adhesive Seal-
ant to the keyway in the crankshaft and insert the
key. With the key in the keyway on the crankshaft,
install the assembly on the crankshaft and camshaft.
(2)
Install the camshaft sprocket bolt and washer
(Fig. 89). Tighten the bolt to 68 N´m (50 ft. lbs.) torque.
(3) To verify correct installation of the timing
chain, rotate the crankshaft 2 revolutions. The cam-
shaft and crankshaft sprocket timing mark should
align (Fig. 88).
(4) Install the crankshaft oil slinger.
(5) Replace the oil seal in the timing case cover
(Refer to 9 - ENGINE/ENGINE BLOCK/CRANK-
SHAFT OIL SEAL - FRONT - REMOVAL).
(6) Install the timing case cover and gasket (Refer
to 9 - ENGINE/VALVE TIMING/TIMING BELT /
CHAIN COVER(S) - INSTALLATION).
(7) With the key installed in the crankshaft key-
way, install the vibration damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
INSTALLATION).
(8) Install the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(9) Install the fan, hub assembly and shroud
(Refer to 7 - COOLING/ENGINE/RADIATOR FAN -
INSTALLATION).
(10) Connect negative cable to battery.
Fig. 88 CrankshaftÐCamshaft Alignment
1 - CAMSHAFT SPROCKET
2 - TIMING MARKS
3 - CRANKSHAFT SPROCKET
Fig. 89 Camshaft Sprocket and Thrust Plate
1 - CAMSHAFT
2 - CAMSHAFT SPROCKET W/INTEGRAL KEY
3 - BOLT AND WASHER
4 - THRUST PLATE
9 - 60 ENGINE - 4.0LWJ