2002 JEEP GRAND CHEROKEE Lubrication

INSTALLATION
CAUTION: When installing the engine into a vehicle
equipped with an automatic transmission, be care-
ful not to damage the trigger wheel on the engine
flywheel.
(1) Attach a lifting device to the engine and lower
the engine into the engine compartment. For easier
installation, it may be necessary to remove the
engine mount bracket as an aid in alignment of the
engine to the transmission.
(2) Align the transmission torque converter hous-
ing with the engine.
(3) Loosely install the converter housing lower
bolts and install the next higher bolt and nut on each
side.
(4) Tighten all 4 bolts finger tight.
(5) Install the engine mount brackets (if removed).
(6) Lower the engine and engine mount brackets
onto the engine compartment cushions. Install the
bolts and finger tighten the nuts.
(7) Remove the engine lifting device.
(8) Raise and support the vehicle.
(9) Install the remaining engine flywheel/converter
housing bolts. Tighten all bolts to 38 N´m (28 ft. lbs.)
torque.
(10) Install the converter-to-drive plate bolts.
(11) Ensure the installation reference marks are
aligned.
(12) Install the engine flywheel/converter housing
access cover.
(13) Install the exhaust pipe support and tighten
the screw.
(14) Install the engine bending brace (Refer to 9 -
ENGINE/ENGINE BLOCK/STRUCT SUPPORT -
INSTALLATION).
(15) Tighten the engine mount-to-bracket bolts.
(16) Connect the vehicle speed sensor wire connec-
tions and tighten the screws.
(17) Connect the exhaust pipe to the manifold.
(18) Install the engine starter motor (Refer to 8 -
ELECTRICAL/STARTING/STARTER MOTOR -
INSTALLATION).
(19) Connect the wires to the engine starter motor
solenoid.
(20) Lower the vehicle.
(21) Connect all the vacuum hoses and wire con-
nectors identified during engine removal.
(22) Remove protective caps from the power steer-
ing hoses.
(23) Connect the hoses to the fittings at the steer-
ing gear. Tighten the nut to 52 N´m (38 ft. lbs.)
torque.
(24) Fill the pump reservoir with fluid.(25) Inspect the fuel supply line o-ring(s) and
replace if necessary. Connect fuel supply line to injec-
tior rail and verify connection by pulling outward on
the line.
(26) Install the fuel line bracket to the intake
manifold.
(27) Connect the coil rail electrical connectors and
oil pressure switch connector.
(28) Connect the following electrical connectors:
²Power steering pressure switch
²Coolant temperature sensor
²Six (6) fuel injector connectors
²Intake air temperature sensor
²Throttle position sensor
²Map sensor
²Crankshaft position sensor
²Oxygen sensor
²Camshaft position sensor
²Generator connector and B+ terminal wire
(29) Connect all previously removed vacuum hoses.
(30) Connect the body ground strap.
(31) Install the throttle, transmission line pres-
sure, and speed control cables to their mounting
bracket and connect them to the throttle body.
(32) Connect the heater hoses at the engine ther-
mostat housing and water pump.
(33) Install the fan assembly (Refer to 7 - COOL-
ING/ENGINE/RADIATOR FAN - INSTALLATION).
(34) Place the fan shroud in position over the fan.
(35) Install the radiator (Refer to 7 - COOLING/
ENGINE/RADIATOR - INSTALLATION).
(36) Connect the service valves to the A/C com-
pressor ports, if equipped with A/C.
(37) Charge the air conditioner system (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(38) Connect the radiator hoses and automatic
transmission fluid cooler pipes, if equipped.
(39) Install the fan shroud to the radiator or radi-
ator/condenser (if equipped with A/C).
(40) Install upper radiator support.
(41) Connect the upper radiator hose and tighten
the clamp.
(42) Connect the lower radiator hose and tighten
the clamp.
(43) Fill crankcase with engine oil. (Refer to
LUBRICATION & MAINTENANCE/FLUID CAPACI-
TIES - SPECIFICATIONS) for correct capacities.
(44) Fill the cooling system with reusable coolant
or new coolant (Refer to 7 - COOLING - STANDARD
PROCEDURE).
(45) Align the hood to the scribe marks. Install the
hood.
(46) Install the air cleaner assembly.
(47) Install the battery and connect the battery
cable.
WJENGINE - 4.0L 9 - 13
ENGINE - 4.0L (Continued)

WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(48) Start the engine, inspect for leaks and correct
the fluid levels, as necessary.
SPECIFICATIONS
ENGINE - 4.0L
DESCRIPTION SPECIFICATION
Engine Type In-line 6 Cylinder
Bore and Stroke 98.4 x 86.69 mm
(3.88 x 3.413 in.)
Displacement 4.0L (242 cu. in.)
Compression Ratio 8.8:1
Firing Order 1±5±3±6±2±4
Lubrication Pressure Feed±Full Flow
Filtration
Cooling System Liquid Cooled±Forced
Circulation
Cylinder Block Cast Iron
Crankshaft Cast Nodular Iron
Cylinder Head Cast Iron
Camshaft Cast Iron
Pistons Aluminum Alloy
Combustion Chamber Dual-Quench
Connecting Rods Cast Malleable Iron
CAMSHAFT
Hydraulic Tappet
ClearanceZero Lash
Bearing Clearance 0.025 to 0.076 mm
(0.001 to 0.003 in.)
DESCRIPTION SPECIFICATION
Bearing Journal Diameter
No. 1 51.54 to 51.56 mm
(2.029 to 2.030 in.)
No. 2 51.28 to 51.31 mm
(2.019 to 2.020 in.)
No. 3 51.03 to 51.05 mm
(2.009 to 2.010 in.)
No. 4 50.78 to 50.80 mm
(1.999 to 2.000 in.)
Base Circle Runout
(MAX)0.03 mm
(0.001 in.)
Valve Lift
Intake 10.350 mm (0.4075 in.)
Exhaust 10.528 mm (0.4145 in.)
Valve Timing
Intake
Opens 12.4É BTDC
Closes 60.9É ABDC
Exhaust
Opens 49.8 BBDC
Closes 29.2É ATDC
Valve Overlap 41.6É
Intake Duration 253.3É
Exhaust Duration 259.É
CRANKSHAFT
End Play 0.038 to 0.165 mm
(0.0015 to 0.0065 in.)
Main Bearing Journal
Diameter
No. 1-6 63.489 to 63.502 mm
(2.4996 to 2.5001 in.)
No. 7 63.449 to 63.487 mm
(2.4980 to 2.4995 in.)
9 - 14 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)

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)

BEARING-TO-JOURNAL CLEARANCE
(1) Wipe the oil from the connecting rod journal.
(2) Use short rubber hose sections over rod bolts
during installation.
(3) Lubricate the upper bearing insert and install
in connecting rod.
(4) Use piston ring compressor to install the rod
and piston assemblies. The oil squirt holes in the
rods must face the camshaft. The arrow on the piston
crown should point to the front of the engine (Fig.
38). Verify that the oil squirt holes in the rods face
the camshaft and that the arrows on the pistons face
the front of the engine.
(5) Install the lower bearing insert in the bearing
cap. The lower insert must be dry. Place strip of Plas-
tigage across full width of the lower insert at the cen-
ter of bearing cap. Plastigage must not crumble in
use. If brittle, obtain fresh stock.
(6) Install bearing cap and connecting rod on the
journal and tighten nuts to 45 N´m (33 ft. lbs.)
torque. DO NOT rotate crankshaft. Plastigage will
smear, resulting in inaccurate indication.
(7) Remove the bearing cap and determine amount
of bearing-to- journal clearance by measuring the
width of compressed Plastigage (Fig. 39).Plastigageshould indicate the same clearance across the
entire width of the insert. If the clearance var-
ies, it may be caused by either a tapered jour-
nal, bent connecting rod or foreign material
trapped between the insert and cap or rod.
(8) If the correct clearance is indicated, replace-
ment of the bearing inserts is not necessary. Remove
the Plastigage from crankshaft journal and bearing
insert. Proceed with installation.
(9) If bearing-to-journal clearance exceeds the
specification, install a pair of 0.0254 mm (0.001 inch)
undersize bearing inserts. All the odd size inserts
must be on the bottom. The sizes of the service
replacement bearing inserts are stamped on the
backs of the inserts. Measure the clearance as
described in the previous steps.
(10) The clearance is measured with a pair of
0.0254 mm (0.001 inch) undersize bearing inserts
installed. This will determine if two 0.0254 mm
(0.001 inch) undersize inserts or another combination
Fig. 36 Locking Tab Inspection
1 - ABNORMAL CONTACT AREA CAUSED BY LOCKING TABS
NOT FULLY SEATED OR BEING BENT
Fig. 37 Scoring Caused by Insufficient Lubrication
or Damaged Crankshaft Journal
Fig. 38 Rod and Piston Assembly Installation
Fig. 39 Measuring Bearing Clearance with
Plastigage
1 - PLASTIGAGE SCALE
2 - COMPRESSED PLASTIGAGE
9 - 34 ENGINE - 4.0LWJ
CONNECTING ROD BEARINGS (Continued)

is needed to provide the correct clearance. Refer to
CONNECTING ROD BEARING FITTING CHART .
CONNECTING ROD BEARING FITTING CHART
CRANKSHAFT JOURNAL CORRESPONDING ROD BEARING INSERT
Color Code Diameter Upper Insert Size Lower Insert Size
Yellow53.2257 - 53.2079 mm
Yellow - Standard Yellow - Standard
(2.0955 - 2.0948 in.)
Orange53.2079 - 53.1901 mm
Yellow - StandardBlue - Undersize (2.0948 - 2.0941 in.)
0.0178 mm (0.0007 in.) 0.025 mm (0.001 in.)
Undersize
Blue53.1901 - 53.1724 mm
Blue - Undersize Blue - Undersize (2.0941 - 2.0934 in.)
0.0356 mm (0.0014 in.) 0.025 mm (0.001 in.) 0.025 mm (0.001 in.)
Undersize
Red52.9717 - 52.9539 mm
Red - Undersize Red - Undersize (2.0855 - 2.0848 in.)
0.254 mm (0.010 in.) 0.254 mm (0.010 in.) 0.254 mm (0.010 in.)
Undersize
(11)FOR EXAMPLE:If the initial clearance was
0.0762 mm (0.003 inch), 0.025 mm (0.001 inch)
undersize inserts would reduce the clearance by
0.025 mm (0.001 inch). The clearance would be 0.002
inch and within specification. A 0.051 mm (0.002
inch) undersize insert would reduce the initial clear-
ance an additional 0.013 mm (0.0005 inch). The
clearance would then be 0.038 mm (0.0015 inch).
(12) Repeat the Plastigage measurement to verify
your bearing selection prior to final assembly.
(13) Once you have selected the proper insert,
install the insert and cap. Tighten the connecting rod
bolts to 45 N´m (33 ft. lbs.) torque.
SIDE CLEARANCE MEASUREMENT
Slide snug-fitting feeler gauge between the con-
necting rod and crankshaft journal flange (Fig. 40).
(Refer to 9 - ENGINE - SPECIFICATIONS). Replace
the connecting rod if the side clearance is not within
specification.
CRANKSHAFT
DESCRIPTION
The crankshaft is constructed of nodular cast iron.
The crankshaft is a crosshaped four throw design
with eight counterweights for balancing purposes.The crankshaft is supported by seven select main
bearings with the number three serving as the thrust
washer location. The main journals of the crankshaft
are cross drilled to improve rod bearing lubrication.
The select fit main bearing markings are located on
the crankshaft counter weights. The crankshaft rear
oil seal is a two piece design. The front oil seal is a
one piece design retained in the timing chain cover
(Fig. 41).
Fig. 40 Checking Connecting Rod Side Clearance -
Typical
WJENGINE - 4.0L 9 - 35
CONNECTING ROD BEARINGS (Continued)

REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the spark plugs (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/SPARK PLUG -
REMOVAL).
(3) Raise the vehicle.
(4) Remove the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL) and oil pump
(Refer to 9 - ENGINE/LUBRICATION/OIL PUMP -
REMOVAL).
(5) Remove main bearing cap brace (Fig. 44).
(6) Remove only one main bearing cap and lower
insert at a time (Fig. 45).
(7) Remove the lower insert from the bearing cap.
(8) Remove the upper insert by LOOSENING (DO
NOT REMOVE) all of the other bearing caps. Now
insert a small cotter pin tool in the crankshaft jour-
nal oil hole. Bend the cotter pin as illustrated to fab-
ricate the tool (Fig. 46). With the cotter pin tool in
place, rotate the crankshaft so that the upper bear-
ing insert will rotate in the direction of its locking
tab. Because there is no hole in the No.3 main jour-
nal, use a tongue depressor or similar soft-faced tool
to remove the bearing insert (Fig. 46). After moving
the insert approximately 25 mm (1 inch), it can be
removed by applying pressure under the tab.
(9) Using the same procedure described above,
remove the remaining bearing inserts one at a time
for inspection.
Fig. 44 Main Bearing Caps and Brace.
1 - BLOCK
2 - MAIN BEARING CAP BRACE
Fig. 45 Removing Main Bearing Caps and Lower
Inserts
1 - CONNECTING ROD JOURNAL
2 - MAIN BEARING CAPS
Fig. 46 Removing Upper Inserts
1 - COTTER PIN
2 - BEARING INSERT
3 - TONGUE DEPRESSOR
WJENGINE - 4.0L 9 - 39
CRANKSHAFT MAIN BEARINGS (Continued)

CRANKSHAFT OIL SEAL -
REAR
REMOVAL
The crankshaft rear main bearing oil seal consists
of two half pieces of viton with a single lip that effec-
tively seals the rear of the crankshaft. Replace the
upper and lower seal halves as a unit to ensure leak-
free operation.
(1) Remove transmission inspection cover.
(2) Remove oil pan. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL PAN - REMOVAL)
(3) Remove main bearing cap brace.
(4) Remove rear main bearing cap (No.7).
(5) Push upper seal out of the groove. Ensure that
the crankshaft and seal groove are not damaged.
(6) Remove lower half of the seal from the bearing
cap.
INSTALLATION
The crankshaft rear main bearing oil seal consists
of two half pieces of viton with a single lip that effec-
tively seals the rear of the crankshaft. Replace the
upper and lower seal halves as a unit to ensure leak-
free operation.
(1) Wipe the seal surface area of the crankshaft
until it is clean.
(2) Apply a thin coat of engine oil.
(3) Coat lip of the seal with engine oil.
(4) Carefully position the upper seal into the
groove in the cylinder block. The lip of the seal faces
toward the front of the engine.
(5) Apply MopartGasket Maker sealer on both
sides of cylinder block as shown in (Fig. 51). The dab
of sealer should be 3 mm (0.125 in.) in diameter.
(6) Apply MopartGasket Maker on the rear bear-
ing cap (Fig. 51). The bead should be 2.3 mm (0.09
in.) in diameter. DO NOT apply sealer to the lip of
the seal.
(7) Position the lower seal into the bearing cap
recess and seat it firmly. Be sure the seal is flush
with the cylinder block pan rail.
(8) Coat the outer curved surface of the lower seal
with soap and the lip of the seal with engine oil.
(9) Install the rear main bearing cap. DO NOT
strike the cap more than twice for proper engage-
ment.
(10) Tighten all main bearing bolts to 108 N´m (80
ft. lbs.) torque.
(11) Install the main bearing cap brace. Tighten
nuts to 47 N´m (35 ft. lbs.).
(12) Install the oil pan gasket and oil pan (Refer to
9 - ENGINE/LUBRICATION/OIL PAN - INSTALLA-
TION).(13) Apply MopartSilicone Rubber Adhesive Seal-
ant on cylinder block to rear main bearing cap cor-
ners and cylinder block to front cover joints (four
places) (Fig. 52)
(14) Install transmission inspection cover.
Fig. 51 Location of Sealer
1-DOWEL
2-SEALER LOCATIONS
3-CYLINDER BLOCK
4-HALFWAY BETWEEN
5-REAR FACE OF CYLINDER BLOCK
6-3mm (0.125 in.)
Fig. 52 Oil Pan
1 - SEALER LOCATIONS
9 - 42 ENGINE - 4.0LWJ

PISTON SIZE CHART
CYLINDER BORE SIZE PISTON LETTER SIZE
98.438 - 98.448 mm
(3.8755 - 3.8759 in.)A
98.448 - 98.458 mm
(3.8759 - 3.8763 in.)B
98.458 - 98.468 mm
(3.8763 - 3.8767 in.)C
98.468 - 98.478 mm
(3.8767 - 3.8771 in.)D
98.478 - 98.488 mm
(3.8771 - 3.8775 in.)E
98.488 - 98.498 mm
(3.8775 - 3.8779 in.)F
REMOVAL
(1) Remove the engine cylinder head cover. (Refer
to 9 - ENGINE/CYLINDER HEAD/CYLINDER
HEAD COVER(S) - REMOVAL).
(2) Remove the rocker arms, bridges and pivots.
(3) Remove the push rods.
(4) Remove the engine cylinder head. (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(5) Position the pistons one at a time near the bot-
tom of the stroke. Use a ridge reamer to remove theridge from the top end of the cylinder walls. Use a
protective cloth to collect the cuttings.
(6) Raise the vehicle.
(7) Drain the engine oil.
(8) Remove the oil pan and gasket. (Refer to 9 -
ENGINE/LUBRICATION/OIL PAN - REMOVAL).
(9) Remove main bearing cap brace (Fig. 58).
(10) Remove the connecting rod bearing caps and
inserts. Mark the caps and rods with the cylinder
bore location. The connecting rods and caps are
stamped with a two letter combination (Fig. 59).
Fig. 57 Bore Gauge
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4 - 49.5 MM (1-15/16 in.)
Fig. 58 Main Bearings Caps and Brace
1 - BLOCK
2 - MAIN BEARING CAP BRACE
Fig. 59 Stamped Connecting Rods and Caps
1 - CONNECTING ROD CAP
2 - CONNECTING ROD
WJENGINE - 4.0L 9 - 45
PISTON & CONNECTING ROD (Continued)