2003 JEEP GRAND CHEROKEE Clamp

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING Ð HEADLAMP
SYSTEM
HEADLAMPS
CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS ARE DIM
WITH ENGINE IDLING1. Loose or corroded battery cables. 1. Clean and secure battery cable clamps
and posts.
OR IGNITION TURNED
OFF2. Loose or worn generator drive belt. 2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system, refer
to Electrical, Charging
4. Battery has insufficient charge. 4. Test battery state-of -charge, refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery, refer to
Electrical,Battery System.
6. Poor lighting circuit Z1-ground. 6. Test for voltage drop across Z1-ground
locations, refer to Electrical, Wiring Digram
Information.
7. Both headlamp bulbs defective. 7. Replace both headlamp bulbs.
HEADLAMP BULBS BURN
OUT1. Charging system output too high. 1. Test and repair charging system, refer
to Electrical, Charging.
FREQUENTLY 2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and
splices, refer to Electrical, Wiring
Information.
HEADLAMPS ARE DIM
WITH ENGINE RUNNING1. Charging system output too low. 1. Test and repair charging system, refer
to Electrical, Wiring Information.
ABOVE IDLE* 2. Poor lighting circuit Z1-ground. 2. Test for voltage drop across Z1-ground
locations, refer to Electrical, Wiring
Information.
3. High resistance in headlamp
circuit.3. Test amperage draw of headlamp
circuit.
4. Both headlamp bulbs defective. 4. Replace both headlamp bulbs.
HEADLAMPS FLASH
RANDOMLY1. Poor lighting circuit Z1-ground. 1. Test for voltage drop across Z1-ground
locations, refer to Electrical, Wiring
Information.
2. High resistance in headlamp
circuit.2. Test amperage draw of headlamp
circuit. Should not exceed 30 amps.
3. Loose or corroded terminals or
splices in circuit.3. Inspect and repair all connectors and
splices, refer to Electrical, Wiring
Information.
HEADLAMPS DO NOT
ILLUMINATE1. No voltage to headlamps. 1. Repair open headlamp circuit, refer to
Electrical, Wiring Information.
2. No Z1-ground at headlamps. 2. Repair circuit ground, refer to Electrical,
Wiring Information.
8L - 12 LAMPS/LIGHTING - EXTERIORWJ
HEADLAMP (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
3. Faulty headlamp switch. 3. Refer to BCM diagnostics.
4. Blown fuse for headlamps. 4. Replace fuse refer to Electrical, Wiring
Information.
5. Broken connector terminal or wire
splice in headlamp circuit.5. Repair connector terminal or wire splice.
6. Both headlamp bulbs defective. 6. Replace both headlamp bulbs.
*Canada vehicles must have lamps ON.
FOG LAMP
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery cables. 1. Clean and secure battery cable clamps
and posts.
2. Loose or worn generator drive belt. 2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system. Refer to
Electrical, Charging,
4. Battery has insufficient charge. 4. Test battery state-of -charge. Refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Electrical,
Battery System.
6. Poor lighting circuit Z1-ground. 6. Test for voltage drop across Z1-ground
locations. Refer to Electrical, Wiring
Information.
FOG LAMP BULBS BURN
OUT FREQUENTLY1. Charging system output too high. 1. Test and repair charging system. Refer to
Electrical, Charging.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and
splices. Refer to Electrical, Wiring
Information.
FOG LAMPS ARE DIM
WITH ENGINE RUNNING
ABOVE IDLE1. Charging system output too low. 1. Test and repair charging system. Refer to
Electrical, Charging.
2. Poor lighting circuit Z1-ground. 2. Test for voltage drop across Z1-ground
locations. Refer to Electrical, Wiring
Information.
3. High resistance in fog lamp circuit. 3. Test amperage draw of fog lamp circuit.
FOG LAMPS FLASH
RANDOMLY1. Poor lighting circuit Z1-ground. 1. Test for voltage drop across Z1-ground
locations. Refer to Electrical, Wiring
Information.
2. High resistance in fog lamp circuit. 2. Test amperage draw of fog lamp circuit.
3. Faulty multifunction switch. 3. Refer to Electrical, Electronic Control
Modules.
4. Loose or corroded terminals or
splices in circuit.4. Inspect and repair all connectors and
splices. Refer to Electrical, Wiring
Information.
WJLAMPS/LIGHTING - EXTERIOR 8L - 13
HEADLAMP (Continued)

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)

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)

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 (2WD Auto) 75 55 Ð
Exhaust Manifold/PipeÐNuts 27 20 Ð
Intake/Exhaust Manifold
Fasteners #1-5 33 24 Ð
Fasteners #6 and 7 14 Ð 126
Fasteners #8-11 33 24 Ð
Flywheel to Converter
HousingÐBolts38 28 Ð
Flywheel to CrankshaftÐBolts 143 105 Ð
Front Cover to BlockÐBolts
1/4-20 7 Ð 60
5/16-18 22 Ð 192
Fuel RailÐBolts/Stud 12 Ð 108
GeneratorÐBolts 57 42 Ð
Generator Bracket to EngineÐ
Bolts47 35 Ð
Idler Pulley to Cylinder
HeadÐBolt47 35 Ð
Main Bearing CapÐBolts 108 80 Ð
Oil Filter 18 Ð 156
Oil Filter Connector to
Adaptor 47 35 Ð
Block 68 50 Ð
Adaptor Bolts 102 50 Ð
Oil GalleyÐPlug 41 30 Ð
Oil PanÐBolts
1/4-20 9.5 Ð 84
5/16-18 15 Ð 132
Oil PanÐDrain Plug 34 25 Ð
Oil Pump
Mounting Bolts 23 Ð 204
Cover Bolts 8 Ð 70
Rocker Arm Assembly to
Cylinder
HeadÐCapscrews 30 21 Ð
Spark Plugs 37 27 ÐDESCRIPTION N´m Ft. In.
Lbs. Lbs.
Starter MotorÐMounting Bolts 45 33 Ð
Thermostat HousingÐBolts 18 Ð 156
Throttle BodyÐBolts 10 Ð 90
Vibration DamperÐBolt 108 80 Ð
Water Pump to BlockÐBolts 23 17 Ð
AIR CLEANER ELEMENT
REMOVAL - 4.0L
(1) Unlatch four clips retaining air cleaner cover to
air cleaner housing (Fig. 6).
Fig. 6 Air Cleaner Assembly Ð4.0L Engine
1 - RESONATOR BOLTS
2 - CLAMPS
3 - AIR DUCT
4 - AIR CLEANER COVER
5 - CLIPS
6 - HOUSING
7 - HOUSING BOLTS (3)
8 - LOWER HOUSING NUTS (3)
9 - RESONATOR
9 - 18 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)

(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)

AIR CLEANER ELEMENT
REMOVAL - 4.7L
(1) Unlatch four clips retaining air cleaner cover to
air cleaner housing (Fig. 8).
(2) Lift cover up and position to the side.
(3) Remove air cleaner element.
INSTALLATION - 4.7L
(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.
Valve Spring Tester C-647
Dial Indicator C-3339
Valve Spring Compressor C-3422-B
Bore Size Indicator C-119
Oil Pressure Gauge C-3292
Piston Ring Compressor C-385
Pressure Tester Kit 7700
Bloc±Chek±Kit C-3685±A
WJENGINE - 4.7L 9 - 83
ENGINE - 4.7L (Continued)

AIR CLEANER HOUSING
REMOVAL - 4.7L
(1) Disconnect air cleaner cover-to-air duct clamp
(Fig. 8).
(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. 8).
(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. 8)and remove 2 resonator mount-
ing bolts (at sides of resonator). Remove resonator
from throttle body by loosening clamp at throttle
body.
INSTALLATION - 4.7L
(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. 8).
(5) Tighten air duct clamp.
CYLINDER HEAD - LEFT
DESCRIPTION
DESCRIPTION - CYLINDER HEAD
The cylinder heads are made of an aluminum alloy.
The cylinder head features two valves per cylinder
with pressed in powdered metal valve guides. The
cylinder heads also provide enclosures for the timing
chain drain, necessitating unique left and right cylin-
der heads.
DESCRIPTION - VALVE GUIDES
The valve guides are made of powered metal and
are pressed into the cylinder head. The guides are
not replaceable or serviceable, and valve guide ream-
ing is not recommended. If the guides are worn
beyond acceptable limits, replace the cylinder heads.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - HYDRAULIC LASH
ADJUSTER
A tappet-like noise may be produced from several
items. Check the following items.
(1) Engine oil level too high or too low. This may
cause aerated oil to enter the adjusters and cause
them to be spongy.
(2) Insufficient running time after rebuilding cylin-
der head. Low speed running up to 1 hour may be
required.
Fig. 8 Air Cleaner Assembly - 4.7L
1 - AIR DUCT
2 - CLAMPS
3 - AIR CLEANER COVER
4 - CLIPS
5 - HOUSING
6 - HOUSING BOLTS (3)
7 - LOWER HOUSING NUTS (3)
8 - RESONATOR BOLTS
9 - RESONATOR
9 - 84 ENGINE - 4.7LWJ
AIR CLEANER ELEMENT (Continued)