2003 JEEP GRAND CHEROKEE Workshop Manual

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Page 1257 of 2199

JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual 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

Page 1258 of 2199

JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual DESCRIPTION SPECIFICATION
Main Bearing Journal
Width
No. 1 27.58 to 27.89 mm
(1.086 to 1.098 in.)
No. 3 32.28 to 32.33 mm
(1.271 to 1.273 in.)
No. 2-4-5-6-7 30.02 to 30.18 mm
(1.182 to 1.188 in.)
Main

Page 1259 of 2199

JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual DESCRIPTION SPECIFICATION
Valve Stem-to-Guide 0.025 to 0.076 mm
Clearance (0.001 to 0.003 in.)
Valve Seat Angle
Intake 44.5É
Exhaust 44.5É
Valve Seat Width 1.02 to 1.52 mm
(0.040 to 0.060 in.)
Valve

Page 1260 of 2199

JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual DESCRIPTION SPECIFICATION
Ring Side Clearance
Compression Rings 0.042 to 0.084 mm
(0.0017 to 0.0033 in.)
Oil Control Rings 0.06 to 0.21 mm
(0.0024 to 0.0083 in.)
Piston Ring Groove
Height
Compression

DESCRIPTION SPECIFICATION
Ring Side Clearance
Compression Rings 0.042 to 0.084 mm
(0.0017 to 0.0033 in.)
Oil Control Rings 0.06 to 0.21 mm
(0.0024 to 0.0083 in.)
Piston Ring Groove
Height
Compression Rings 1.530 to 1.555 mm
(0.0602 to 0.0612 in.)
Oil Control Ring 4.035 to 4.060 mm
(0.1589 to 0.1598 in.)
Piston Ring Groove
Diameter
No.1 Compression Ring 88.39 to 88.65 mm
(3.48 to 3.49 in.)
No.2 Compression Ring 87.63 to 87.88 mm
(3.45 to 3.46 in.)
Oil Control Ring 89.66 to 89.92 mm
(3.53 to 3.54 in.)
Piston Pin Bore Diameter 23.650 to 23.658 mm
(0.9312 to 0.9315 in.)
Piston Pin Diameter 23.637 to 23.640 mm
(0.9306 to 0.9307 in.)
Piston-to-Pin Clearance 0.0102 to 0.0208 mm
(0.0005 to 0.0009 in.)
Piston-to-Pin Connecting
Rod (Press Fit) 8.9 kN (2000 lbf.)
OIL PUMP
Gear-to-Body Clearance 0.051 to 0.102 mm
(Radial) (0.002 to 0.004 in.)
Gear-to-Body Clearance
(Radial) Preferred 0.051 mm (0.002 in.)
Gear End Clearance 0.051 to 0.152 mm
Plastigage (0.002 to 0.006 in.)
Gear End Clearance
Plastigage (Preferred) 0.051 mm (0.002 in.)
Gear End Clearance 0.1016 to 0.2032 mm
Feeler Gauge (0.004 to 0.008 in.)DESCRIPTION SPECIFICATION
Gear End Clearance
Feeler Gauge (Preferred) 0.1778 mm (0.007 in.)
Oil Pressure
At Idle Speed 89.6 kPa (13 psi)
At 1600 rpm & Higher 255 to 517 kPa
(37 to 75 psi)
Oil Pressure Relief 517 kPa (75 psi)
TORQUE - 4.0L ENGINE
DESCRIPTION N´m Ft. In.
Lbs. Lbs.
A/C CompressorÐBolts 28 Ð 250
Block HeaterÐNut 2 Ð 16
Camshaft SprocketÐBolt 68 50 Ð
Camshaft Thrust Plate to
Cylinder BlockÐScrews 24 18 Ð
Clutch Cover to FlywheelÐBolts 54 40 Ð
Coil Bracket to BlockÐBolts 22 Ð 192
Connecting RodÐNuts 45 33 Ð
Cylinder BlockÐDrain Plugs 34 25 Ð
Cylinder HeadÐBolts 135 100 Ð
Cylinder Head CoverÐBolts 10 Ð 85
Distributor ClampÐBolts 23 Ð 204
Engine MountsÐFront
Support Bracket Bolts 61 45 Ð
Support Cushion Bolts/Nuts 41 30 Ð
Support Cushion Bracket Bolts 54 40 Ð
Support Cushion Bracket Stud
Nuts41 30 Ð
Support Cushion Thru-Bolt 65 48 Ð
Engine MountsÐRear
Crossmember to Sill BoltsÐ
(Automatic) 41 30 Ð
Insulator Stud AssemblyÐNut 41 30 Ð
Support Cushion/
CrossmemberÐ
Nuts 22 Ð 192
Support Cushion/BracketÐNuts
(Manual) 75 55 Ð
WJENGINE - 4.0L 9 - 17
ENGINE - 4.0L (Continued)

Page 1261 of 2199

JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual DESCRIPTION N´m Ft. In.
Lbs. Lbs.
Transmission Support Bracket
ÐBolt (Manual) 46 34 Ð
Transmission Support Bracket/
CushionÐBolt (4WD Auto) 75 55 Ð
Transmission Support Adaptor
BracketÐBolts (2W

Page 1262 of 2199

JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual (2) Lift cover up and position to the side.
(3) Remove air cleaner element.
INSTALLATION - 4.0L
(1) Clean inside of air cleaner housing before
installing new element.
(2) Install air cleaner element i

(2) Lift cover up and position to the side.
(3) Remove air cleaner element.
INSTALLATION - 4.0L
(1) Clean inside of air cleaner housing before
installing new element.
(2) Install air cleaner element into housing.
(3) Latch clips and clamp cover down to secure. Be
sure air cleaner cover is properly seated to air
cleaner housing.
AIR CLEANER HOUSING
REMOVAL - 4.0L
(1) Disconnect air cleaner cover-to-air duct clamp
(Fig. 6).
(2) Disconnect air duct at housing.
(3)Each of the 3 air cleaner housing mount-
ing bolts is attached with 2 nuts (an upper nut
and lower nut). DO NOT REMOVE BOLTS. To
prevent stripping bolts, only remove lower
nuts. The lower housing nuts are located under
left front inner fender (Fig. 6).
(a) To gain access to lower nuts, raise vehicle.
(b) Remove clips retaining rubber inner fender
shield.
(c) Pry back shield enough to gain access to
lower nuts.
(d) Remove 3 nuts.
(e) Remove air cleaner assembly from vehicle.
(4) If resonator is to be removed, disconnect
breather tube at resonator, disconnect air duct clamp
at resonator (Fig. 6)and remove 1 resonator mount-
ing bolt. Remove resonator from throttle body by
loosening clamp (Fig. 7).
INSTALLATION - 4.0L
(1) Position air cleaner assembly to body and
install 3 nuts. Tighten nuts to 10 N´m (93 in. lbs.)
torque.To prevent excessive vibration transmit-
ted through housing, the nuts must be properly
torqued. Do not overtighten nuts.
(2) If resonator was removed: Install resonator and
bolts. Tighten bolts to 4 N´m (35 in. lbs.) torque.
Tighten clamp at throttle body to 4 N´m (35 in. lbs.)
torque.
(3) Position fender liner and install clips.
(4) Connect air duct at housing (Fig. 6).
(5) Tighten air duct clamp.
CYLINDER HEAD
DESCRIPTION
The cylinder head is made of cast iron containing
twelve valves made of chrome plated heat resistant
steel, valve stem seals, springs, retainers and keep-
ers. The cylinder head and valve seats can be resur-
faced for service purposes.
The valve guides are integral to the cylinder head,
They are not replaceable. However, they are service-
able.
The cylinder head uses dual quench-type design
combustion chambers which cause turbulence in the
cylinders allowing faster burning of the air/fuel mix-
ture, resulting in better fuel economy (Fig. 8).
REMOVAL
NOTE: This procedure can be done with the engine
in or out of the vehicle.
(1) Disconnect the battery negative cable.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAIN COCK WITH THE SYSTEM HOT AND PRES-
SURIZED BECAUSE SERIOUS BURNS FROM THE
COOLANT CAN OCCUR.
Fig. 7 RESONATOR CLAMP - 4.0L
1 - RESONATOR
2 - AIR DUCT
3 - CLAMP
WJENGINE - 4.0L 9 - 19
AIR CLEANER ELEMENT (Continued)

Page 1263 of 2199

JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual (2) Drain the coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE) and disconnect the hoses
at the engine thermostat housing and the water
pump inlet. DO NOT waste reusable coolant. If the
solution is

(2) Drain the coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE) and disconnect the hoses
at the engine thermostat housing and the water
pump inlet. DO NOT waste reusable coolant. If the
solution is clean and is being drained only to service
the engine or cooling system, drain the coolant into a
clean container for reuse.
(3) Remove the air cleaner assembly (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - REMOVAL).
(4) Remove the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(5) Remove the capscrews, bridge and pivot assem-
blies and rocker arms (Refer to 9 - ENGINE/CYLIN-
DER HEAD/ROCKER ARM / ADJUSTER ASSY -
REMOVAL).
(6) Remove the push rods.Retain the push rods,
bridges, pivots and rocker arms in the same
order as removed.
(7) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(8) Remove the A/C compressor mounting bolts
and secure the compressor to the side.
(9) Remove the power steering pump and bracket
from the intake manifold and water pump. Set the
pump and bracket aside. DO NOT disconnect the
hoses.
(10) Perform the Fuel System Pressure Release
procedure. (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE).
(11) Disconnect the fuel supply line at the fuel rail.(12) Remove the intake and exhaust manifolds
from the engine cylinder head (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
(13) Remove the coil rail (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/COIL RAIL - REMOV-
AL).
(14) Remove spark plugs (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/SPARK PLUG - REMOV-
AL).
(15) Disconnect the temperature sending unit wire
connector.
(16) Remove the engine cylinder head bolts. Bolt
No.14 cannot be removed until the head is moved for-
ward (Fig. 9). Pull bolt No.14 out as far as it will go
and then suspend the bolt in this position (tape
around the bolt).
(17) Remove the engine cylinder head and gasket
(Fig. 9).
(18) If this was the first time the bolts were
removed, put a paint dab on the top of the bolt. If the
bolts have a paint dab on the top of the bolt or it
isn't known if they were used before, discard the
bolts.
(19) Stuff clean lint free shop towels into the cyl-
inder bores.
NOTE: If the valves, springs, or seals are to be
inspected/replaced at this time, (Refer to 9 -
ENGINE/CYLINDER HEAD/INTAKE/EXHAUST
VALVES & SEATS - STANDARD PROCEDURE) for
proper inspection procedures.
Fig. 8 Cylinder Head 4.0L Engine
1 - CYLINDER HEAD BOLTS
2 - CYLINDER HEAD GASKET
3 - CYLINDER HEAD
Fig. 9 Engine Cylinder
1 - CYLINDER HEAD BOLTS
2 - CYLINDER HEAD GASKET
3 - CYLINDER HEAD
9 - 20 ENGINE - 4.0LWJ
CYLINDER HEAD (Continued)

Page 1264 of 2199

JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual CLEANING
Thoroughly clean the engine cylinder head and cyl-
inder block mating surfaces. Clean the intake and
engine exhaust manifold and engine cylinder head
mating surfaces. Remove all gasket materi

CLEANING
Thoroughly clean the engine cylinder head and cyl-
inder block mating surfaces. Clean the intake and
engine exhaust manifold and engine cylinder head
mating surfaces. Remove all gasket material and car-
bon.
Check to ensure that no coolant or foreign material
has fallen into the tappet bore area.
Remove the carbon deposits from the combustion
chambers and top of the pistons.
INSPECTION
Use a straightedge and feeler gauge to check the
flatness of the engine cylinder head and block mating
surfaces.
INSTALLATION
NOTE: This procedure can be done with the engine
in or out of the vehicle.
The engine cylinder head gasket is a composition
gasket. The gasket is to be installed DRY.DO NOT
use a gasket sealing compound on the gasket.
If the engine cylinder head is to be replaced and
the original valves used, measure the valve stem
diameter. Only standard size valves can be used with
a service replacement engine cylinder head unless
the replacement head valve stem guide bores are
reamed to accommodate oversize valve stems.
Remove all carbon buildup and reface the valves.
(1) Remove the shop towels from the cylinder
bores. Coat the bores with clean engine oil.
(2) Position the engine cylinder head gasket (with
the numbers facing up) using the alignment dowels
in the cylinder block, to position the gasket.
CAUTION: Engine cylinder head bolts should be
reused only once. Replace the head bolts if they
were used before or if they have a paint dab on the
top of the bolt.
(3) With bolt No.14 held in place (tape around
bolt), install the engine cylinder head over the same
dowels used to locate the gasket. Remove the tape
from bolt No.14.
(4) Coat the threads of stud bolt No.11 with Loc-
tite 592 sealant, or equivalent.
(5) Tighten the engine cylinder head bolts in
sequence according to the following procedure (Fig.
10).
CAUTION: During the final tightening sequence,
bolt No.11 will be tightened to a lower torque than
the rest of the bolts. DO NOT overtighten bolt
No.11.(a) Tighten all bolts in sequence (1 through 14)
to 30 N´m (22 ft. lbs.) torque.
(b) Tighten all bolts in sequence (1 through 14)
to 61 N´m (45 ft. lbs.) torque.
(c) Check all bolts to verify they are set to 61
N´m (45 ft. lbs.) torque.
(d) Tighten bolts in sequence:
²Bolts 1 through 10 to 149 N´m (110 ft. lbs.)
torque.
²Bolt 11 to 135 N´m (100 ft. lbs.) torque.
²Bolts 12 through 14 to 149 N´m (110 ft. lbs.)
torque.
CYLINDER HEAD BOLTS
POSITION DESCRIPTION
1,4,5,12,13 1/2 in.-13 BOLT
8,9 1/2 in.-13 BOLT WITH DOWEL
POINT
2,3,6,7,10,11,14 1/2 in.-13 WITH 7/16 in.-14 STUD
END
All bolts are 12 point drives for rocker cover clearance
(e) Check all bolts in sequence to verify the cor-
rect torque.
(f) If not already done, clean and mark each bolt
with a dab of paint after tightening. Should you
encounter bolts which were painted in an earlier
service operation, replace them.
(6) Install the spark plugs (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/SPARK PLUG - INSTAL-
LATION).
(7) Connect the temperature sending unit wire
connector.
(8) Install the ignition coil rail (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/COIL RAIL -
INSTALLATION).
(9) Install the intake and exhaust manifolds (Refer
to 9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION).
(10) Install the fuel line.
(11) Attach the power steering pump and bracket.
Fig. 10 Engine Cylinder Head Bolt Tightening
Sequence
WJENGINE - 4.0L 9 - 21
CYLINDER HEAD (Continued)

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