2002 JEEP GRAND CHEROKEE Lubrication

If the leakage occurs at the crankshaft rear oil seal
area:
(1) Disconnect the battery.
(2) Raise the vehicle.
(3) Remove torque converter or clutch housing
cover and inspect rear of block for evidence of oil.
Use a black light to check for the oil leak:
(a) Circular spray pattern generally indicates
seal leakage or crankshaft damage.
(b) Where leakage tends to run straight down,
possible causes are a porous block, distributor seal,
camshaft bore cup plugs oil galley pipe plugs, oil
filter runoff, and main bearing cap to cylinder
block mating surfaces.
(4) If no leaks are detected, pressurize the crank-
case as outlined in the, Inspection (Engine oil Leaks
in general)
CAUTION: Do not exceed 20.6 kPa (3 psi).
(5) If the leak is not detected, very slowly turn the
crankshaft and watch for leakage. If a leak is
detected between the crankshaft and seal while
slowly turning the crankshaft, it is possible the
crankshaft seal surface is damaged. The seal area on
the crankshaft could have minor nicks or scratches
that can be polished out with emery cloth.
CAUTION: Use extreme caution when crankshaft
polishing is necessary to remove minor nicks and
scratches. The crankshaft seal flange is especially
machined to complement the function of the rear oil
seal.
(6) For bubbles that remain steady with shaft
rotation, no further inspection can be done until dis-
assembled.
OIL
STANDARD PROCEDURE - ENGINE OIL
WARNING: NEW OR USED ENGINE OIL CAN BE
IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED BY
INTERNAL COMBUSTION, CAN BE HAZARDOUS TO
YOUR HEALTH. THOROUGHLY WASH EXPOSED
SKIN WITH SOAP AND WATER. DO NOT WASH
SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR
SOLVENTS, HEALTH PROBLEMS CAN RESULT. DO
NOT POLLUTE, DISPOSE OF USED ENGINE OIL
PROPERLY.
ENGINE OIL SPECIFICATION
CAUTION: Do not use non-detergent or straight
mineral oil when adding or changing crankcase
lubricant. Engine failure can result.
API SERVICE GRADE CERTIFIED
Use an engine oil that is API Service Grade Certi-
fied. MOPARtprovides engine oils that conform to
this service grade.
SAE VISCOSITY
An SAE viscosity grade is used to specify the vis-
cosity of engine oil. Use only engine oils with multi-
ple viscosities such as 5W-30 or 10W-30 in the 4.7L
engines.The 4.7L H.O. uses 10W-30 oil only.These
are specified with a dual SAE viscosity grade which
indicates the cold-to-hot temperature viscosity range.
Select an engine oil that is best suited to your par-
ticular temperature range and variation (Fig. 90).
ENERGY CONSERVING OIL
An Energy Conserving type oil is recommended for
gasoline engines. The designation of ENERGY CON-
SERVING is located on the label of an engine oil con-
tainer.
CONTAINER IDENTIFICATION
Standard engine oil identification notations have
been adopted to aid in the proper selection of engine
oil. The identifying notations are located on the label
of engine oil plastic bottles and the top of engine oil
cans (Fig. 91).
OIL LEVEL INDICATOR (DIPSTICK)
The engine oil level indicator is located on the
right side of the the 4.7L engine. (Fig. 92).
Fig. 90 Temperature/Engine Oil Viscosity - 4.7L
Engine
9 - 130 ENGINE - 4.7LWJ
LUBRICATION (Continued)

CRANKCASE OIL LEVEL INSPECTION
CAUTION: Do not overfill crankcase with engine oil,
pressure loss or oil foaming can result.
Inspect engine oil level approximately every 800
kilometers (500 miles). Unless the engine has exhib-
ited loss of oil pressure, run the engine for about five
minutes before checking oil level. Checking engine oil
level on a cold engine is not accurate.
To ensure proper lubrication of an engine, the
engine oil must be maintained at an acceptable level.
The acceptable levels are indicated between the ADD
and SAFE marks on the engine oil dipstick.
(1) Position vehicle on level surface.
(2) With engine OFF, allow approximately ten min-
utes for oil to settle to bottom of crankcase, remove
engine oil dipstick.(3) Wipe dipstick clean.
(4) Install dipstick and verify it is seated in the
tube.
(5) Remove dipstick, with handle held above the
tip, take oil level reading.
(6) Add oil if level is below the SAFE ZONE on
dipstick.
ENGINE OIL CHANGE
Change engine oil at mileage and time intervals
described in Maintenance Schedules.
Run engine until achieving normal operating tem-
perature.
(1) Position the vehicle on a level surface and turn
engine off.
(2) Remove oil fill cap.
(3) Hoist and support vehicle on safety stands.
(4) Place a suitable drain pan under crankcase
drain.
(5) Remove drain plug from crankcase and allow
oil to drain into pan. Inspect drain plug threads for
stretching or other damage. Replace drain plug if
damaged.
(6) Install drain plug in crankcase.
(7) Remove oil filter (Refer to 9 - ENGINE/LUBRI-
CATION/OIL FILTER - REMOVAL).
(8) Lower vehicle and fill crankcase with specified
type and amount of engine oil described in this sec-
tion.
(9) Install oil fill cap.
(10) Start engine and inspect for leaks.
(11) Stop engine and inspect oil level.
USED ENGINE OIL DISPOSAL
Care should be exercised when disposing used
engine oil after it has been drained from a vehicle
engine. Refer to the WARNING at beginning of this
section.
OIL FILTER
REMOVAL
All engines are equipped with a high quality full-
flow, disposable type oil filter. DaimlerChrysler Cor-
poration recommends a Mopartor equivalent oil
filter be used.
(1) Position a drain pan under the oil filter.
(2) Using a suitable oil filter wrench loosen filter.
(3) Rotate the oil filter counterclockwise (Fig. 93)to
remove it from the cylinder block oil filter boss.
(4) When filter separates from cylinder block oil
filter boss, tip gasket end upward to minimize oil
spill. Remove filter from vehicle.
NOTE: Make sure filter gasket was removed with fil-
ter.
Fig. 91 Engine Oil Container Standard Notations
Fig. 92 Engine Oil Dipstick 4.7L Engine
1 - TRANSMISSION DIPSTICK
2 - ENGINE OIL DIPSTICK
3 - ENGINE OIL FILL CAP
WJENGINE - 4.7L 9 - 131
OIL (Continued)

NOTE: When installing oil pan gasket/windage tray,
start four pan bolts at each corner before tightening
oil pickup tube. This will keep pan gasket in align-
ment.
(3) Install oil pump pick-up tube using a new
O-ring. First tighten bolt at O-ring end of tube to 28
N´m (20 ft. lbs.). Tighten remain tube support fasten-
ers to 28 N´m (20 ft. lbs.).
(4) Install oil pan and tighten fasteners to 15 N´m
(11 ft. lbs.) (Fig. 95).
(5) Reconnect transmission oil cooler lines to oil
pan stud bolt.
(6) Install starter (Refer to 8 - ELECTRICAL/
STARTING/STARTER MOTOR - INSTALLATION).
(7) Install exhaust system Y-pipe.
(8) Install structural cover (Refer to 9 - ENGINE/
ENGINE BLOCK/STRUCTURAL COVER - INSTAL-
LATION).
(9) Lower vehicle.
(10) Fill engine with proper amount of oil (Refer to
LUBRICATION & MAINTENANCE/FLUID TYPES -
SPECIFICATIONS).
(11) Connect negative cable to battery.
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The 3±wire, solid-state engine oil pressure sensor
(sending unit) is located in an engine oil pressure
gallery.
OPERATION
The oil pressure sensor uses three circuits. They are:
²A 5±volt power supply from the Powertrain Con-
trol Module (PCM)
²A sensor ground through the PCM's sensor
return
²
A signal to the PCM relating to engine oil pressure
The oil pressure sensor has a 3±wire electrical
function very much like the Manifold Absolute Pres-
sure (MAP) sensor. Meaning different pressures
relate to different output voltages.
A 5±volt supply is sent to the sensor from the PCM
to power up the sensor. The sensor returns a voltage
signal back to the PCM relating to engine oil pres-
sure. This signal is then transferred (bussed) to the
instrument panel on either a CCD or PCI bus circuit
(depending on vehicle line) to operate the oil pressure
gauge and the check gauges lamp. Ground for the
sensor is provided by the PCM through a low-noise
sensor return.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Raise vehicle on hoist.
(3) Remove front splash shield.
(4) Disconnect oil pressure sender wire (Fig. 96).
(5) Remove the pressure sender (Fig. 96).
INSTALLATION
(1) Install oil pressure sender.
(2) Connect oil pressure sender wire.
(3) Install front splash shield.
(4) Lower vehicle.
(5) Connect the negative battery cable.
Fig. 95 Oil Pan Tightening Sequence
Fig. 96 Oil Pressure Sending Unit
1 - BELT
2 - OIL PRESSURE SENSOR
3 - OIL FILTER
4 - ELEC. CONNECTOR
WJENGINE - 4.7L 9 - 133
OIL PAN (Continued)

OIL PUMP
REMOVAL
(1) Remove the oil pan and pick-up tube (Refer to
9 - ENGINE/LUBRICATION/OIL PAN - REMOVAL).
(2) Remove the timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(3) Remove the timing chains and tensioners
(Refer to 9 - ENGINE/VALVE TIMING/TIMING
BELT/CHAIN AND SPROCKETS - REMOVAL).
(4) Remove the four bolts, primary timing chain
tensioner and the oil pump.
DISASSEMBLY
(1) Remove oil pump cover screws and lift off cover
plate.
(2) Remove pump inner and outer rotors.
NOTE: Once the oil pressure relief valve, cup plug,
and pin are removed, the pump assembly must be
replaced.
(3) If it is necessary to remove the pressure relief
valve, drive the roll pin from pump housing and
remove cup plug, spring and valve.
CLEANING
(1) Wash all parts in a suitable solvent.
INSPECTION
CAUTION: Oil pump pressure relief valve and
spring should not be removed from the oil pump. If
these components are disassembled and or
removed from the pump the entire oil pump assem-
bly must be replaced.
(1) Clean all parts thoroughly. Mating surface of
the oil pump housing should be smooth. If the pump
cover is scratched or grooved the oil pump assembly
should be replaced.
(2) Lay a straight edge across the pump cover sur-
face (Fig. 97). If a 0.025 mm (0.001 in.) feeler gauge
can be inserted between the cover and the straight
edge the oil pump assembly should be replaced.
(3) Measure the thickness of the outer rotor (Fig.
98). If the outer rotor thickness measures at 12.005
mm (0.472 in.) or less the oil pump assembly must be
replaced.(4) Measure the diameter of the outer rotor. If the
outer rotor diameter measures at 85.925 mm (3.382
in.) or less the oil pump assembly must be replaced.
(5) Measure the thickness of the inner rotor (Fig.
99). If the inner rotor thickness measures at 12.005
mm (0.472 in.) or less then the oil pump assembly
must be replaced.
(6) Slide outer rotor into the body of the oil pump.
Press the outer rotor to one side of the oil pump body
and measure clearance between the outer rotor and
the body (Fig. 100). If the measurement is 0.235mm
(0.009 in.) or more the oil pump assembly must be
replaced.
(7) Install the inner rotor in the into the oil pump
body. Measure the clearance between the inner and
outer rotors (Fig. 101). If the clearance between the
rotors is .150 mm (0.006 in.) or more the oil pump
assembly must be replaced.
(8) Place a straight edge across the body of the oil
pump (between the bolt holes), if a feeler gauge of
.095 mm (0.0038 in.) or greater can be inserted
between the straightedge and the rotors, the pump
must be replaced (Fig. 102).
NOTE: The 4.7 Oil pump is released as an assem-
bly. There are no DaimlerChrysler part numbers for
Sub-Assembly components. In the event the oil
pump is not functioning or out of specification it
must be replaced as an assembly.
Fig. 97 Checking Oil Pump Cover Flatness
1 - STRAIGHT EDGE
2 - FEELER GAUGE
3 - OIL PUMP COVER
9 - 134 ENGINE - 4.7LWJ

ASSEMBLY
(1) Wash all parts in a suitable solvent and inspect
carefully for damage or wear.
(2) Install inner and outer rotors
(3) Install oil pump cover plate and install cover
bolts and tighten them to 12 N´m (105 in. lbs.).
(4) Prime oil pump before installation by filling
rotor cavity with engine oil.
(5) If oil pressure is low and pump is within spec-
ifications, inspect for worn engine bearings or other
causes for oil pressure loss.
INSTALLATION
(1) Position the oil pump onto the crankshaft and
install two oil pump retaining bolts.
(2) Position the primary timing chain tensioner
and install the two retaining bolts.
(3) Tighten the oil pump and primary timing chain
tensioner retaining bolts to 28 N´m (250 in. lbs.) in
the sequence shown (Fig. 103).
(4) Install the secondary timing chain tensioners
and timing chains (Refer to 9 - ENGINE/VALVETIMING/TIMING BELT/CHAIN AND SPROCKETS -
INSTALLATION).
(5) Install the timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(6) Install the pick-up tube and oil pan (Refer to 9
- ENGINE/LUBRICATION/OIL PAN - INSTALLA-
TION).
Fig. 98 Measuring Outer Rotor Thickness
Fig. 99 Measuring Inner Rotor Thickness
Fig. 100 Measuring Outer Rotor Clearance in
1 - FEELER GAUGE
2 - OUTER ROTOR
Fig. 101 Measuring Clearance Between Rotors
1 - OUTER ROTOR
2 - FEELER GAUGE
3 - INNER ROTOR
WJENGINE - 4.7L 9 - 135
OIL PUMP (Continued)

INSPECTION
(1) Inspect the exhaust manifold for cracks in the
mating surface and at every mounting bolt hole.
(2) Using a straight edge and a feeler gauge, check
the mating surface for warp and twist.
(3) Inspect the manifold to exhaust pipe mating
surface for cracks, gouges, or other damage that
would prevent sealing.
INSTALLATION
(1) Install exhaust manifold and gasket from below
engine compartment.
(2) Install lower exhaust manifold fasteners. DO
NOT tighten until all fasteners are in place.
(3) Lower vehicle and install upper exhaust mani-
fold fasteners. Tighten all manifold bolts starting at
center and working outward to 25 N´m (18 ft. lbs.).
CAUTION: Over tightening heat shield fasteners,
may cause shield to distort and/or crack.
(4) Install exhaust manifold heat shield. Tighten
fasteners to 8 N´m (72 in. lbs.), then loosen 45
degrees.
(5) Install starter and fasteners.
(6) Connect exhaust pipe to manifold.
(7) Connect heater hoses at engine.
(8) Install fastener attaching A/C accumulator.
(9) Install A/C compressor and fasteners.
(10) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(11) Install washer bottle and battery tray assem-
bly.
(12) Install PDC.
(13) Install battery and connect cables.
(14) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
VALVE TIMING
DESCRIPTION - TIMING DRIVE SYSTEM
The timing drive system has been designed to pro-
vide quiet performance and reliability to support a
non-free wheelingengine. Specifically the intake
valves are non-free wheeling and can be easily dam-
aged with forceful engine rotation if camshaft-to-
crankshaft timing is incorrect. The timing drive
system consists of a primary chain and two second-
ary timing chain drives (Fig. 109).
OPERATION - TIMING DRIVE SYSTEM
The primary timing chain is a single inverted tooth
type. The primary chain drives the large fifty tooth
idler sprocket directly from a 25 tooth crankshaftsprocket. Primary chain motion is controlled by a
pivoting leaf spring tensioner arm and a fixed guide.
The arm and the guide both use nylon plastic wear
faces for low friction and long wear. The primary
chain receives oil splash lubrication from the second-
ary chain drive and oil pump leakage. The idler
sprocket assembly connects the primary and second-
ary chain drives. The idler sprocket assembly con-
sists of two integral thirty tooth sprockets and a fifty
tooth sprocket that is splined to the assembly. The
spline joint is a non ± serviceable press fit anti rattle
type. A spiral ring is installed on the outboard side of
the fifty tooth sprocket to prevent spline disengage-
ment. The idler sprocket assembly spins on a station-
ary idler shaft. The idler shaft is press-fit into the
cylinder block. A large washer on the idler shaft bolt
and the rear flange of the idler shaft are used to con-
trol sprocket thrust movement. Pressurized oil is
routed through the center of the idler shaft to pro-
vide lubrication for the two bushings used in the
idler sprocket assembly.
There are two secondary drive chains, both are
inverted tooth type, one to drive the camshaft in each
SOHC cylinder head. There are no shaft speed
changes in the secondary chain drive system. Each
secondary chain drives a thirty tooth cam sprocket
directly from the thirty tooth sprocket on the idler
sprocket assembly. A fixed chain guide and a hydrau-
lic oil damped tensioner are used to maintain tension
in each secondary chain system. The hydraulic ten-
sioners for the secondary chain systems are fed pres-
surized oil from oil reservoir pockets in the block.
Each tensioner also has a mechanical ratchet system
that limits chain slack if the tensioner piston bleeds
down after engine shut down. The tensioner arms
and guides also utilize nylon wear faces for low fric-
tion and long wear. The secondary timing chains
receive lubrication from a small orifice in the ten-
sioners. This orifice is protected from clogging by a
fine mesh screen which is located on the back of the
hydraulic tensioners.
STANDARD PROCEDURE
STANDARD PROCEDURE - ENGINE TIMING -
VERIFICATION
CAUTION: The 4.7L is a non free-wheeling design
engine. Therefore, correct engine timing is critical.
NOTE: Components referred to as left hand or right
hand are as viewed from the drivers position inside
the vehicle.
WJENGINE - 4.7L 9 - 141
EXHAUST MANIFOLD - RIGHT (Continued)

BINDING AND STICKING
CONDITION POSSIBLE CAUSE CORRECTION
DIFFICULT TO TURN WHEEL
STICKS OR BINDS1. Low fluid level. 1. Fill to proper level.
2. Tire pressure. 2. Adjust tire pressure.
3. Steering component. 3. Inspect and lube.
4. Loose belt. 4. Adjust or replace.
5. Low pump pressure. 5. Pressure test and replace if
necessary.
6. Column shaft coupler binding. 6. Replace coupler.
7. Steering gear worn or out of
adjustment.7. Repair or replace gear.
8. Ball joints binding. 8. Inspect and repair as necessary.
9. Belt routing. 9. Verify belt routing is correct.
4.7L Hydraulic fan motor steering output
lowPressure / Flow test fans steering
output flow
INSUFFICIENT ASST. OR POOR RETURN TO CENTER
CONDITION POSSIBLE CAUSE CORRECTION
HARD TURNING OR MOMENTARY
INCREASE IN TURNING EFFORT1. Tire pressure. 1. Adjust tire pressure.
2. Low fluid level. 2. Fill to proper level.
3. Loose belt. 3. Adjust or replace.
4. Lack of lubrication. 4. Inspect and lubricate steering and
suspension compnents.
5. Low pump pressure or flow. 5. Pressure and flow test and repair
as necessary.
6. Internal gear leak. 6. Pressure and flow test, and repair
as necessary.
7. Belt routing. 7. Verify belt routing is correct.
4.7L8. Low flow / pressure from fan
motor8. Pressure and flow test and repair
as necessary.
STEERING WHEEL
DOES NOT WANT TO RETURN TO
CENTER POSITION1. Tire pressure. 1. Adjust tire pressure.
2. Wheel alignment. 2. Align front end.
3. Lack of lubrication. 3. Inspect and lubricate steering and
suspension compnents.
4. High friction in steering gear. 4. Test and adjust as necessary.
5. Ball joints binding. 5. Inspect and repair as necessary.
NOTE:
Some roads will cause a vehicle to drift, due to the crown in the road.
WJSTEERING 19 - 3
STEERING (Continued)

HOSES - 4.7L
DESCRIPTION
DESCRIPTION - 1/2º PRESSURE HOSE
The hose consists of two metal ends and a rubber
center with quick connect nuts at both ends. The
hose connects the power steering pump to the
hydraulic fan motor and is clipped to the fan shroud
(Fig. 8). Lubrication must be used on the quick con-
nect nuts and o-rings when installing.
DESCRIPTION - 1/2º RETURN HOSE
The fan motor return line is a molded rubber hose
that is clamped at the hydraulic motor and the power
steering reservoir (Fig. 9).
DESCRIPTION - 3/8º PRESSURE HOSE
The hose consists of two metal ends and two rub-
ber sections one of which contains a tuning cable
(Fig. 10). The hose is clipped in two places to the fan
shroud. Lubrication must be used on the o-rings
when installing.
DESCRIPTION - 3/8º GEAR OUTLET HOSE
The gear outlet line consists of a metal section that
connects to the gear and a rubber section that clamps
to the steering cooler inlet tube (Fig. 11).
DESCRIPTION - 3/8º RETURN HOSE
The return hose is a formed rubber hose that con-
nects the steering cooler outlet tube to the power
steering reservoir (Fig. 12). It is clamped at both
ends.
OPERATION
OPERATION - 1/2º PRESSURE HOSE
The 1/2º pressure hose is used to transfer high
pressure power steering fluid from the power steer-
ing pump to the engine cooling fan motor (Fig. 8).
OPERATION - 1/2º RETURN HOSE
The power steering return line returns low pres-
sure excess flow from the hydraulic fan motor back to
the power steering pump (Fig. 9).
Fig. 8 1/2(PRESSURE HOSE
1 - 1/29PRESSURE HOSE
2 - POWER STEERING PUMP
3 - STEERING GEAR
Fig. 9 1/2(RETURN HOSE
1 - 1/29RETURN HOSE
2 - HOSE CLAMP
Fig. 10 3/8(PRESSURE HOSE
1 - 3/89PRESSURE HOSE
2 - STEERING GEAR
19 - 38 PUMPWJ