head JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual

STANDARD PROCEDURE
STANDARD PROCEDURE - REPAIR DAMAGED
OR WORN THREADS
CAUTION: Be sure that the tapped holes maintain
the original center line.
Damaged or worn threads can be repaired. Essen-
tially, this repair consists of:
²Drilling out worn or damaged threads.
²Tapping the hole with a special Heli-Coil Tap, or
equivalent.
²Installing an insert into the tapped hole to bring
the hole back to its original thread size.
STANDARD PROCEDURE - FORM-IN-PLACE
GASKETS AND SEALERS
There are numerous places where form-in-place
gaskets are used on the engine. Care must be taken
when applying form-in-place gaskets to assure
obtaining the desired results.Do not use form-in-
place gasket material unless specified.Bead size,
continuity, and location are of great importance. Too
thin a bead can result in leakage while too much can
result in spill-over which can break off and obstruct
fluid feed lines. A continuous bead of the proper
width is essential to obtain a leak-free gasket.
There are numerous types of form-in-place gasket
materials that are used in the engine area. Mopart
Engine RTV GEN II, MopartATF-RTV, and Mopart
Gasket Maker gasket materials, each have different
properties and can not be used in place of the other.
MOPARtENGINE RTV GEN II
MopartEngine RTV GEN II is used to seal com-
ponents exposed to engine oil. This material is a spe-
cially designed black silicone rubber RTV that
retains adhesion and sealing properties when
exposed to engine oil. Moisture in the air causes the
material to cure. This material is available in three
ounce tubes and has a shelf life of one year. After one
year this material will not properly cure. Always
inspect the package for the expiration date before
use.
MOPARtATF RTV
MopartATF RTV is a specifically designed black
silicone rubber RTV that retains adhesion and seal-
ing properties to seal components exposed to auto-
matic transmission fluid, engine coolants, and
moisture. This material is available in three ounce
tubes and has a shelf life of one year. After one year
this material will not properly cure. Always inspect
the package for the expiration date before use.
MOPARtGASKET MAKER
MopartGasket Maker is an anaerobic type gasket
material. The material cures in the absence of airwhen squeezed between two metallic surfaces. It will
not cure if left in the uncovered tube. The anaerobic
material is for use between two machined surfaces.
Do not use on flexible metal flanges.
MOPARtGASKET SEALANT
MopartGasket Sealant is a slow drying, perma-
nently soft sealer. This material is recommended for
sealing threaded fittings and gaskets against leakage
of oil and coolant. Can be used on threaded and
machined parts under all temperatures. This mate-
rial is used on engines with multi-layer steel (MLS)
cylinder head gaskets. This material also will pre-
vent corrosion. MopartGasket Sealant is available in
a 13 oz. aerosol can or 4oz./16 oz. can w/applicator.
FORM-IN-PLACE GASKET AND SEALER
APPLICATION
Assembling parts using a form-in-place gasket
requires care but it's easier then using precut gas-
kets.
MopartGasket Maker material should be applied
sparingly 1 mm (0.040 in.) diameter or less of sealant
to one gasket surface. Be certain the material sur-
rounds each mounting hole. Excess material can eas-
ily be wiped off. Components should be torqued in
place within 15 minutes. The use of a locating dowel
is recommended during assembly to prevent smear-
ing material off the location.
MopartEngine RTV GEN II or ATF RTV gasket
material should be applied in a continuous bead
approximately 3 mm (0.120 in.) in diameter. All
mounting holes must be circled. For corner sealing, a
3.17 or 6.35 mm (1/8 or 1/4 in.) drop is placed in the
center of the gasket contact area. Uncured sealant
may be removed with a shop towel. Components
should be torqued in place while the sealant is still
wet to the touch (within 10 minutes). The usage of a
locating dowel is recommended during assembly to
prevent smearing material off the location.
MopartGasket Sealant in an aerosol can should be
applied using a thin, even coat sprayed completely
over both surfaces to be joined, and both sides of a
gasket. Then proceed with assembly. Material in a
can w/applicator can be brushed on evenly over the
sealing surfaces. Material in an aerosol can should be
used on engines with multi-layer steel gaskets.
STANDARD PROCEDURE - ENGINE GASKET
SURFACE PREPARATION
To ensure engine gasket sealing, proper surface
preparation must be performed, especially with the
use of aluminum engine components and multi-layer
steel cylinder head gaskets.
Neveruse the following to clean gasket surfaces:
²Metal scraper
9 - 70 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)

DESCRIPTION SPECIFICATION
PISTON RINGS
Ring Gap
Top Compression Ring 0.37 - 0.63 mm
(0.0146 - 0.0249 in.)
Second Compression
Ring0.37 - 0.63 mm
(0.0146 - 0.0249 in.)
Oil Control (Steel Rails) 0.25 - 0.76 mm
(0.0099 - 0.30 in.)
Side Clearance
Top Compression Ring .051 - .094 mm
(0.0020 - 0.0037 in.)
Second Compression
Ring0.040 - 0.080 mm
(0.0016 - 0.0031 in.)
Oil Ring (Steel Ring) .019 - .229 mm
(.0007 - .0091 in.)
Ring Width
Top Compression Ring 1.472 - 1.490 mm
(0.057 - 0.058 in.)
Second Compression
Ring1.472 - 1.490 mm
(0.057 - 0.058 in.)
Oil Ring (Steel Rails) 0.445 - 0.470 mm
(0.017 - 0.018 in.)
CONNECTING RODS
Bearing Clearance 0.010 - 0.048 mm
(0.0004 - 0.0019 in.)
Side Clearance 0.10 - 0.35 mm
(0.004 - 0.0138 in.)
Piston Pin Bore Diameter .022 - .045 mm
(Interference Fit) (0.0009 - 0.0018 in.)
Bearing Bore Out of
Round0.004 mm
(MAX) (0.0002 in.)
Total Weight (Less
Bearing)555 grams (19.5771
ounces)
CRANKSHAFT
Main BearingJournal
Diameter 63.488 - 63.512 mm
(2.4996 - 2.5005 in.)DESCRIPTION SPECIFICATION
Bearing Clearance 0.018 - 0.052 mm
(0.0008 - 0.0021 in.)
Out of Round (MAX) 0.005 mm (0.0002 in.)
Taper (MAX) 0.008 mm (0.0004 in.)
End Play 0.052 - 0.282 mm
(0.0021 - 0.0112 in.)
End Play (MAX) 0.282 mm (0.0112 in)
Connecting Rod
Journal
Diameter 50.992 - 51.008 mm
(2.0076 - 2.0082 in.)
Bearing Clearance 0.015 - 0.055 mm
(0.0006 -0.0022 in.)
Out of Round (MAX) 0.005 mm (0.0002 in.)
Taper (MAX) 0.008 mm (0.0004 in.)
CAMSHAFT
Bore Diameter 26.02 - 26.04 mm
(1.0245 - 1.0252 in.)
Bearing Journal Diameter 25.975 - 25.995 mm
(1.0227 - 1.0235 in.)
Bearing Clearance 0.025 - 0.065 mm
(0.001 - 0.0026 in.)
Bearing Clearance (MAX) 0.065 mm (0.0026 in.)
End Play .075 - .200 mm
(0.003 - 0.0079 in.)
End Play (MAX) .200 mm (0.0079 in.)
VALVE TIMING
Intake
Opens (ATDC) 3.6É
Closes (ATDC) 247.1É
Duration 243.5É
Exhaust
Opens (BTDC) 232.5É
Closes (ATDC) 21.2É
Duration 253.70É
Valve Overlap 17.6É
VA LV E S
Face Angle 45É - 45.5É
Head Diameter
Intake 48.52 - 48.78 mm
(1.9103 - 1.9205 in.)
WJENGINE - 4.7L 9 - 75
ENGINE - 4.7L (Continued)

DESCRIPTION SPECIFICATION
Exhaust 36.87 - 37.13 mm
1.4516 - 1.4618 in.)
Length (Overall)
Intake 113.45 - 114.21 mm
(4.4666 - 4.4965)
Exhaust 114.92 - 115.68 mm
(4.5244 - 4.5543 in.)
Stem Diameter
Intake 6.931 - 6.957 mm
(0.2729 - 0.2739 in.)
Exhaust 6.902 - 6.928 mm
(0.2717 - 0.2728 in.)
Stem - to - Guide
Clearance
Intake .018 - .069 mm
(0.0008 - 0.0028 in.)
Exhaust .047 - .098 mm
(0.0019 - 0.0039 in.)
Max. Allowable Stem -
to -
Guide Clearance
(Rocking
Method)
Intake 0.069 mm (0.0028 in.)
Exhaust 0.098 mm (0.0039 in.)
Valve Lift (Zero Lash)
Intake 11.25 mm (0.443 in.)
Exhaust 10.90 mm (0.4292 in.)
VALVE SPRING
Free Length (Approx)
Intake and Exhaust 48.6 mm (1.9134 in.)
Spring Force (Valve
Closed)
Intake and Exhaust 315.5 - 352.5 N @ 40.89
mm
(70.92722 - 79.24515 lbs.
@ 1.6099 in.)DESCRIPTION SPECIFICATION
Spring Force (Valve
Open)
Intake and Exhaust 786.0 - 860.0 N @ 29.64
mm
176.6998 - 193.3357 lbs.
@ 1.167 in.)
Number of Coils
Intake and Exhaust 6.69
Wire Diameter
Intake and Exhaust 4.2799 - 4.3561 mm
(0.1685 - 0.1715 in.)
Installed Height (Spring
Seat to Bottom of
Retainer)
Nominal
Intake 40.97 mm (1.613 in.)
Exhaust 40.81 mm (1.606 in.)
CYLINDER HEAD
Gasket Thickness
(Compressed) .7 mm (0.0276 in.)
Valve Seat Angle 44.5É - 45.0É
Valve Seat Runout (MAX) 0.051 mm (0.002 in.)
Valve Seat Width
Intake 1.75 - 2.36 mm
(0.0698 - 0.0928 in.)
Exhaust 1.71 - 2.32 mm
(0.0673 - 0.0911 in.)
Guide Bore Diameter
(Std.)6.975 - 7.00 mm
(0.2747 - 0.2756 in.)
Cylinder Head Warpage
(Flatness) 0.0508 mm (0.002 in.)
OIL PUMP
Clearance Over Rotors /
End Face (MAX).035 - .095 mm
(0.0014 - 0.0038 in.)
Cover Out - of -Flat
(MAX).025 mm (0.001 in.)
Inner and Outer Rotor
Thickness 12.02 mm (0.4731 in.)
9 - 76 ENGINE - 4.7LWJ
ENGINE - 4.7L (Continued)

DESCRIPTION SPECIFICATION
Side Clearance 0.10 - 0.35 mm
(0.004 - 0.0138 in.)
Piston Pin Bore Diameter 24.045 - 24.035 mm
(0.94665 - 0.94625 in.)
Bearing Bore Out of
Round0.004 mm
(MAX) (0.0002 in.)
Total Weight (Less
Bearing)555 grams (19.5771
ounces)
CRANKSHAFT
Main BearingJournal
Diameter 63.488 - 63.512 mm
(2.4996 - 2.5005 in.)
Bearing Clearance 0.018 - 0.052 mm
(0.0008 - 0.0021 in.)
Out of Round (MAX) 0.005 mm (0.0002 in.)
Taper (MAX) 0.008 mm (0.0004 in.)
End Play 0.052 - 0.282 mm
(0.0021 - 0.0112 in.)
End Play (MAX) 0.282 mm (0.0112 in)
Connecting Rod
Journal
Diameter 50.992 - 51.008 mm
(2.0076 - 2.0082 in.)
Bearing Clearance 0.015 - 0.055 mm
(0.0006 -0.0022 in.)
Out of Round (MAX) 0.005 mm (0.0002 in.)
Taper (MAX) 0.008 mm (0.0004 in.)
CAMSHAFT
Bore Diameter 26.02 - 26.04 mm
(1.0245 - 1.0252 in.)
Bearing Journal Diameter 25.975 - 25.995 mm
(1.0227 - 1.0235 in.)
Bearing Clearance 0.025 - 0.065 mm
(0.001 - 0.0026 in.)
Bearing Clearance (MAX) 0.065 mm (0.0026 in.)
End Play .075 - .200 mm
(0.003 - 0.0079 in.)
End Play (MAX) .200 mm (0.0079 in.)DESCRIPTION SPECIFICATION
VALVE TIMING
Intake
Opens (BTDC) 3.0É
Closes (ATDC) 233.0É
Duration 236.0É
Exhaust
Opens (BTDC) 235.0É
Closes (ATDC) 15.0É
Duration 250.0É
Valve Overlap 18.0É
VA LV E S
Face Angle 45É - 45.5É
Head Diameter
Intake 48.52 - 48.78 mm
(1.9103 - 1.9205 in.)
Exhaust 36.87 - 37.13 mm
1.4516 - 1.4618 in.)
Length (Overall)
Intake 113.45 - 114.21 mm
(4.4666 - 4.4965)
Exhaust 114.92 - 115.68 mm
(4.5244 - 4.5543 in.)
Stem Diameter
Intake 6.931 - 6.957 mm
(0.2729 - 0.2739 in.)
Exhaust 6.902 - 6.928 mm
(0.2717 - 0.2728 in.)
Stem - to - Guide
Clearance
Intake .018 - .069 mm
(0.0008 - 0.0028 in.)
Exhaust .047 - .098 mm
(0.0019 - 0.0039 in.)
Max. Allowable Stem -
to -
Guide Clearance
(Rocking
Method)
Intake 0.069 mm (0.0028 in.)
Exhaust 0.098 mm (0.0039 in.)
9 - 78 ENGINE - 4.7LWJ
ENGINE - 4.7L (Continued)

DESCRIPTION SPECIFICATION
Valve Lift (Zero Lash)
Intake 12.00 mm (0.4724 in.)
Exhaust 10.90 mm (0.4292 in.)
VALVE SPRING
Free Length (Approx)
Intake and Exhaust 48.92 mm (1.9259 in.)
Spring Force (Valve
Closed)
Intake and Exhaust 380.0 +/- 19.0 N @ 40.12
mm
(85.4274 lbs. @ 1.5795
in.)
Spring Force (Valve
Open)
Intake and Exhaust 1030.0 +/- 46.0 N @
28.12 mm
231.5532 lbs. @ 1.107
in.)
Number of Coils
Intake and Exhaust 7.30
Wire Diameter
Intake and Exhaust 4.77 +/- 0.03 mm x
3.80+/- .03mm
Installed Height (Spring
Seat to Bottom of
Retainer)
Nominal
Intake 40.97 mm (1.613 in.)
Exhaust 40.81 mm (1.606 in.)
CYLINDER HEAD
Gasket Thickness
(Compressed) .7 mm (0.0276 in.)
Valve Seat Angle 44.5É - 45.0É
Valve Seat Runout (MAX) 0.051 mm (0.002 in.)
Valve Seat Width
Intake 1.75 - 2.36 mm
(0.0698 - 0.0928 in.)
Exhaust 1.71 - 2.32 mm
(0.0673 - 0.0911 in.)
Guide Bore Diameter
(Std.)6.975 - 7.00 mm
(0.2747 - 0.2756 in.)DESCRIPTION SPECIFICATION
Cylinder Head Warpage
(Flatness) 0.0508 mm (0.002 in.)
OIL PUMP
Clearance Over Rotors /
End Face (MAX).035 - .095 mm
(0.0014 - 0.0038 in.)
Cover Out - of -Flat
(MAX).025 mm (0.001 in.)
Inner and Outer Rotor
Thickness 12.02 mm (0.4731 in.)
Outer Rotor Clearance
(MAX).235 mm (.0093 in.)
Outer Rotor Diameter
(MIN)85.925 mm (0.400 in.)
Tip Clearance Between
Rotors
(MAX) .150 mm (0.006 in.)
OIL PRESSURE
At Curb Idle Speed
(MIN)*25 kPa (4 psi)
@ 3000 rpm 170 - 758 kPa (25 - 110
psi)
* CAUTION: If pressure is zero at curb idle, DO
NOT run
engine at 3000 rpm.
TORQUE
DESCRIPTION N´m Ft. In.
Lbs. Lbs.
Camshaft
Non - Oiled Sprocket Bolt 122 90 Ð
Bearing Cap Bolts 11 Ð 100
Timing Chain CoverÐBolts 54 40 Ð
Connecting Rod CapÐBolts 27 20 Ð
PLUS 90É TURN
Bed PlateÐBolts Refer to Procedure
Crankshaft DamperÐBolt 175 130 Ð
Cylinder HeadÐBolts
M11 Bolts 81 60 Ð
M8 Bolts 26 19 Ð
Cylinder Head CoverÐBolts 12 Ð 105
Exhaust ManifoldÐBolts 25 18 Ð
WJENGINE - 4.7L 9 - 79
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)