2002 JEEP GRAND CHEROKEE Cylinder head removal

CONDITION POSSIBLE CAUSE CORRECTION
1. ENGINE MISSES ON
ACCELERATION1. Spark plugs dirty or incorrectly
gapped.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG -
CLEANING).
2. Dirt in fuel system. 2. Clean fuel system.
3. Burned, warped or pitted valves. 3. Replcae as necessary.
4. Faulty coil. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION COIL -
REMOVAL).
1. ENGINE MISSES AT HIGH
SPEED1. Spark plugs dirty or incorrectly
gapped.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG -
CLEANING).
2. Faulty coil. 2. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION COIL -
REMOVAL).
3. Dirt or water in fuel system. 3. Clean system and replace fuel filter.
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTIONS
NOISY VALVES 1. High or low oil level in crankcase. 1. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
SPECIFICATIONS).
2. Thin or diluted oil. 2. Change oil and filter.
3. Low oil pressure. 3. Check oil pump, if Ok, check rod
and main bearings for excessive wear.
4. Dirt in lash adjusters. 4. Replace as necessary.
5. Worn rocker arms. 5. Replace as necessary.
6. Worn lash adjusters 6. Replace as necessary.
7. Worn valve guides. 7. (Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES &
SEATS - STANDARD PROCEDURE).
8. Excessive runout of valve seats
on valve faces.8. Service valves and valve seats.
(Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES &
SEATS - STANDARD PROCEDURE).
CONNECTING ROD NOISE 1. Insufficient oil supply. 1. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
SPECIFICATIONS).
2. Low oil pressure. 2. Check oil pump, if Ok, check rod
and main bearings for excessive wear.
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Replace as necessary.
5. Connecting rod journal out-of-
round.5. Service or replace crankshaft.
6. Misaligned connecting rods. 6. Replace bent connecting rods.
9 - 66 ENGINE - 4.7LWJ
ENGINE - 4.7L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
OIL PRESSURE DROP 1. Low oil level. 1. Check and correct oil level.
2. Faulty oil pressure sending unit. 2. Replace sending unit (Refer to 9 -
ENGINE/LUBRICATION/OIL
PRESSURE SENSOR/SWITCH -
REMOVAL).
3. Low oil pressure. 3. Check oil pump and bearing
clearance.
4. Clogged oil filter. 4. Replace oil filter (Refer to 9 -
ENGINE/LUBRICATION/OIL FILTER -
REMOVAL).
5. Worn oil pump. 5. Replace oil pump (Refer to 9 -
ENGINE/LUBRICATION/OIL PUMP -
REMOVAL).
6. Thin or diluted oil. 6. Change oil and filter.
7. Excessive bearing clearance. 7. Replace as necessary.
8. Oil pump relief valve stuck. 8. Replace oil pump (Refer to 9 -
ENGINE/LUBRICATION/OIL PUMP -
REMOVAL).
9. Oil pick up tube loose, damaged
or clogged.9. Replace as necessary.
OIL PUMPING AT RINGS;
SPARK PLUGS FOULING1. Worn or damaged rings. 1. Hone cylinder bores and replace
rings.
2. Carbon in oil ring slots. 2. Replace rings (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON
RINGS - STANDARD PROCEDURE).
3. Incorrect ring size installed. 3. Replace rings (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON
RINGS - STANDARD PROCEDURE).
4. Worn valve guides. 4. Ream guides and replace valves
(Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES &
SEATS - STANDARD PROCEDURE).
5. Leaking valve guide seals. 5. Replace valve guide seals.
DIAGNOSIS AND TESTING - CYLINDER
COMPRESSION PRESSURE
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs.
(3) Secure the throttle in the wide-open position.(4) Disable the fuel system (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - DESCRIPTION).
(5) Remove the ASD relay (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/AUTO SHUT DOWN
RELAY - REMOVAL).
(6) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(7) Record the compression pressure on the 3rd
revolution. Continue the test for the remaining cylin-
ders.
(8) (Refer to 9 - ENGINE - SPECIFICATIONS) for
the correct engine compression pressures.
9 - 68 ENGINE - 4.7LWJ
ENGINE - 4.7L (Continued)

²Abrasive pad or paper to clean cylinder block
and head
²High speed power tool with an abrasive pad or a
wire brush (Fig. 2)
NOTE: Multi-Layer Steel (MLS) head gaskets require
a scratch free sealing surface.
Only use the following for cleaning gasket surfaces:
²Solvent or a commercially available gasket
remover
²Plastic or wood scraper (Fig. 2)
²Drill motor with 3M RolocŸ Bristle Disc (white
or yellow) (Fig. 2)
CAUTION: Excessive pressure or high RPM (beyond
the recommended speed), can damage the sealing
surfaces. The mild (white, 120 grit) bristle disc is
recommended. If necessary, the medium (yellow, 80
grit) bristle disc may be used on cast iron surfaces
with care.
STANDARD PROCEDURE - ENGINE CORE AND
OIL GALLERY PLUGS
Using a blunt tool such as a drift and a hammer,
strike the bottom edge of the cup plug. With the cup
plug rotated, grasp firmly with pliers or other suit-
able tool and remove plug (Fig. 3).
CAUTION: Do not drive cup plug into the casting as
restricted cooling can result and cause serious
engine problems.Thoroughly clean inside of cup plug hole in cylin-
der block or head. Be sure to remove old sealer.
Lightly coat inside of cup plug hole with Mopart
Stud and Bearing Mount. Make certain the new plug
is cleaned of all oil or grease. Using proper drive
plug, drive plug into hole so that the sharp edge of
the plug is at least 0.5 mm (0.020 in.) inside the
lead-in chamfer.
It is not necessary to wait for curing of the sealant.
The cooling system can be refilled and the vehicle
placed in service immediately.
REMOVAL
(1) Disconnect the battery negative cable.
(2) Remove the front fascia.
(3) Raise vehicle on hoist.
(4) Remove exhaust crossover pipe from exhaust
manifolds.
(5) Disconnect two ground straps from the lower
left hand side and one ground strap from the lower
right hand side of the engine.
(6) Disconnect crankshaft position sensor. (Fig. 4)
(7) Remove structural cover (Refer to 9 - ENGINE/
ENGINE BLOCK/STRUCTURAL COVER - REMOV-
AL).
(8) Remove starter. (Refer to 8 - ELECTRICAL/
STARTING/STARTER MOTOR - REMOVAL).
(9) Remove rubber splash shield.
(10) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(11) Remove torque converter bolts.
(12) Remove transmission to engine mounting
bolts.
Fig. 2 Proper Tool Usage For Surface Preparation
1 - ABRASIVE PAD
2 - 3M ROLOCŸ BRISTLE DISC
3 - PLASTIC/WOOD SCRAPER
Fig. 3 Core Hole Plug Removal
1 - CYLINDER BLOCK
2 - REMOVE PLUG WITH PLIERS
3 - STRIKE HERE WITH HAMMER
4 - DRIFT PUNCH
5 - CUP PLUG
WJENGINE - 4.7L 9 - 71
ENGINE - 4.7L (Continued)

(13) Disconnect the engine block heater power
cable from the block heater.
(14) Lower vehicle.
(15) Remove throttle body resonator assembly and
inlet hose.
(16) Disconnect throttle and speed control cables.
(17) Disconnect tube from both the left and right
side crankcase breathers, then remove the breathers
(Fig. 5).
(18) Discharge A/C system (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).(19) Remove radiator fan (Refer to 7 - COOLING/
ENGINE/RADIATOR FAN - REMOVAL) and acces-
sory drive belt (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - REMOVAL).
(20) Remove A/C compressor (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - REMOVAL).
(21) Disconnect transmission oil cooler lines at the
radiator.
(22) Disconnect radiator lower hose at the thermo-
stat housing.
(23) Remove A/C condenser (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C CON-
DENSER - REMOVAL).
(24) Remove radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(25) Remove generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - REMOVAL).
(26) Disconnect the two heater hoses from the tim-
ing chain cover.
(27) Disconnect engine harness at the following
points :
²Intake air temperature (IAT) sensor (Fig. 6)
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold absolute pressure (MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
(28) Release fuel rail pressure (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - STANDARD PROCE-
DURE) then disconnect the fuel supply quick connect
fitting at the fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/QUICK CONNECT FITTING -
STANDARD PROCEDURE).
(29) Remove power steering pump and position out
of the way.
(30) Disconnect ground straps from the left side of
the engine.
(31) Install Engine Lifting Fixture Special Tool
8347 (Fig. 7)following these steps.
²Holding the lifting fixture at a slight angle, slide
the large bore in the front plate over the hex portion
of the lifting stud.
²Position the two remaining fixture arms onto
the two lifting studs in the cylinder heads.
²Pull foward and upward on the lifting fixture so
that the lifting stud rest in the slotted area below the
large bore.
²Secure the lifting fixture to the three studs
using three 7/16 ± 14 N/C locknuts.
²Make sure the lifting loop in the lifting fixture is
in the last hole (closest to the throttle body) to min-
imize the angle of engine during removal.
Fig. 4 Crankshaft Position Sensor
1 - CRANKSHAFT POSITION SENSOR
2 - CYLINDER HEAD COVER
3 - CAMSHAFT POSITION SENSOR
4 - RIGHT SIDE CYLINDER BLOCK
Fig. 5 Crankcase Breather Connection Points
1 - CRANKCASE BREATHERS
9 - 72 ENGINE - 4.7LWJ
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)

(3) Turn engine off and let set for a few minutes
before restarting. Repeat this several times after
engine has reached normal operating temperature.
(4) Low oil pressure.
(5) The oil restrictor in cylinder head gasket or the
oil passage to the cylinder head is plugged with
debris.
(6) Air ingested into oil due to broken or cracked
oil pump pick up.
(7) Worn valve guides.
(8) Rocker arm ears contacting valve spring
retainer.
(9) Rocker arm loose, adjuster stuck or at maxi-
mum extension and still leaves lash in the system.
(10) Oil leak or excessive cam bore wear in cylin-
der head.
(11) Faulty lash adjuster.
a. Check lash adjusters for sponginess while
installed in cylinder head and cam on camshaft at
base circle. Depress part of rocker arm over adjuster.
Normal adjusters should feel very firm. Spongy
adjusters can be bottomed out easily.
b. Remove suspected lash adjusters, and replace.
c. Before installation, make sure adjusters are at
least partially full of oil. This can be verified by little
or no plunger travel when lash adjuster is depressed.
DIAGNOSIS AND TESTINGÐCYLINDER HEAD
GASKET
A cylinder head gasket leak can be located between
adjacent cylinders or between a cylinder and the
adjacent water jacket.
Possible indications of the cylinder head gasket
leaking between adjacent cylinders are:
²Loss of engine power
²Engine misfiring
²Poor fuel economy
Possible indications of the cylinder head gasket
leaking between a cylinder and an adjacent water
jacket are:
²Engine overheating
²Loss of coolant
²Excessive steam (white smoke) emitting from
exhaust
²Coolant foaming
CYLINDER-TO-CYLINDER LEAKAGE TEST
To determine if an engine cylinder head gasket is
leaking between adjacent cylinders, follow the proce-
dures in Cylinder Compression Pressure Test (Refer
to 9 - ENGINE - DIAGNOSIS AND TESTING). An
engine cylinder head gasket leaking between adja-
cent cylinders will result in approximately a 50±70%
reduction in compression pressure.
CYLINDER-TO-WATER JACKET LEAKAGE TEST
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING WITH COOLANT PRES-
SURE CAP REMOVED.
VISUAL TEST METHOD
With the engine cool, remove the coolant pressure
cap. Start the engine and allow it to warm up until
thermostat opens.
If a large combustion/compression pressure leak
exists, bubbles will be visible in the coolant.
COOLING SYSTEM TESTER METHOD
WARNING: WITH COOLING SYSTEM TESTER IN
PLACE, PRESSURE WILL BUILD UP FAST. EXCES-
SIVE PRESSURE BUILT UP, BY CONTINUOUS
ENGINE OPERATION, MUST BE RELEASED TO A
SAFE PRESSURE POINT. NEVER PERMIT PRES-
SURE TO EXCEED 138 kPa (20 psi).
Install Cooling System Tester 7700 or equivalent to
pressure cap neck. Start the engine and observe the
tester's pressure gauge. If gauge pulsates with every
power stroke of a cylinder a combustion pressure
leak is evident.
CHEMICAL TEST METHOD
Combustion leaks into the cooling system can also
be checked by using Bloc-Chek Kit C-3685-A or
equivalent. Perform test following the procedures
supplied with the tool kit.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Raise the vehicle on a hoist.
(3) Disconnect the exhaust pipe at the left side
exhaust manifold.
(4) Drain the engine coolant. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(5) Lower the vehicle.
(6) Remove the intake manifold. (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL).
(7) Remove the cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(8) Remove accessory drive belt. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(9) Remove the power steering pump and set
aside.
(10) Rotate the crankshaft until the damper tim-
ing mark is aligned with TDC indicator mark (Fig.
9).
WJENGINE - 4.7L 9 - 85
CYLINDER HEAD - LEFT (Continued)

(11) Verify the V8 mark on the camshaft sprocket
is at the 12 o'clock position (Fig. 11). Rotate the
crankshaft one turn if necessary.
(12) Remove the crankshaft damper. (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(13) Remove the timing chain cover. (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(14) Lock the secondary timing chains to the idler
sprocket using Special Tool 8515 (Fig. 10).
NOTE: Mark the secondary timing chain prior to
removal to aid in installation.
(15) Mark the secondary timing chain, one link on
each side of the V8 mark on the camshaft drive gear
(Fig. 11).
(16) Remove the left side secondary chain ten-
sioner. (Refer to 9 - ENGINE/VALVE TIMING/TIM-
ING BELT/CHAIN AND SPROCKETS - REMOVAL).
(17) Remove the cylinder head access plug (Fig.
12).
(18) Remove the left side secondary chain guide.
(Refer to 9 - ENGINE/VALVE TIMING/TIMING
BELT/CHAIN AND SPROCKETS - REMOVAL).
(19) Remove the retaining bolt and the camshaft
drive gear.CAUTION: Do not allow the engine to rotate. Severe
damage to the valve train can occur.
CAUTION: Do not overlook the four smaller bolts at
the front of the cylinder head. Do not attempt to
remove the cylinder head without removing these
four bolts.
NOTE: The cylinder head is attached to the cylinder
block with fourteen bolts.
(20) Remove the cylinder head retaining bolts.
(21) Remove the cylinder head and gasket. Discard
the gasket.
CAUTION: Do not lay the cylinder head on its gas-
ket sealing surface, due to the design of the cylin-
der head gasket any distortion to the cylinder head
sealing surface may prevent the gasket from prop-
erly sealing resulting in leaks.
CLEANING
To ensure engine gasket sealing, proper surface
preparation must be performed, especially with the
use of aluminum engine components. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
Fig. 9 Engine Top Dead Center
1 - TIMING CHAIN COVER
2 - CRANKSHAFT TIMING MARKS
Fig. 10 Using Special Tool 8515 to Hold Chains to
Idler Sprocket.
1 - LOCK ARM
2 - RIGHT CAMSHAFT CHAIN
3 - SECONDARY CHAINS RETAINING PINS (4)
4 - IDLER SPROCKET
5 - LEFT CAMSHAFT CHAIN
6 - SPECIAL TOOL 8515
9 - 86 ENGINE - 4.7LWJ
CYLINDER HEAD - LEFT (Continued)

REMOVAL
CAUTION: When the timing chain is removed and
the cylinder heads are still installed, DO NOT force-
fully rotate the camshafts or crankshaft indepen-
dently of each other. Severe valve and/or piston
damage can occur.
CAUTION: When removing the cam sprocket, timing
chains or camshaft, Failure to use Special Tool
8350 will result in hydraulic tensioner ratchet over
extension, requiring timing chain cover removal to
reset the tensioner ratchet.
(1) Remove cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) Set engine to TDC cylinder #1, camshaft
sprocket V8 marks at the 12 o'clock position.
(3) Mark one link on the secondary timing chain
on both sides of the V8 mark on the camshaft
sprocket to aid in installation.
CAUTION: Do not hold or pry on the camshaft tar-
get wheel (Located on the right side camshaft
sprocket) for any reason, Severe damage will occur
to the target wheel resulting in a vehicle no start
condition.(4) Loosen butDO NOTremove the camshaft
sprocket retaining bolt. Leave the bolt snug against
the sprocket.
NOTE: The timing chain tensioners must be
secured prior to removing the camshaft sprockets.
Failure to secure tensioners will allow the tension-
ers to extend, requiring timing chain cover removal
in order to reset tensioners.
CAUTION: Do not force wedge past the narrowest
point between the chain strands. Damage to the
tensioners may occur.
(5) Position Special Tool 8350 timing chain wedge
between the timing chain strands, tap the tool to
securely wedge the timing chain against the ten-
sioner arm and guide (Fig. 15).
NOTE: When gripping the camshaft, place the pliers
on the tube portion of the camshaft only. Do not
grip the lobes or the sprocket areas.
(6) Hold the camshaft with adjustable pliers while
removing the camshaft sprocket bolt and sprocket
(Fig. 16).
Fig. 15 Securing Timing Chain Tensioners Using Timing Chain Wedge
1 - LEFT CYLINDER HEAD
2 - RIGHT CYLINDER HEAD3 - SPECIAL TOOL 8350 WEDGE
4 - SPECIAL TOOL 8350 WEDGE
WJENGINE - 4.7L 9 - 89
CAMSHAFT(S) - LEFT (Continued)