2003 JEEP GRAND CHEROKEE 4.7 air filter

(4) Remove two radiator mounting bolts.
(5) Disconnect both transmission cooler lines from
radiator.
(6) Disconnect electrical connector for the fan con-
trol solenoid.
(7) Disconnect the power steering cooler line from
cooler and filter.
(8) Disconnect the radiator upper and lower hoses.
(9) Disconnect the overflow hose from radiator.
(10) Remove the air inlet duct at the grill.(11) The lower part of radiator is equipped with
two alignment dowel pins (Fig. 35). They are located
on the bottom of radiator tank and fit into rubber
grommets. These rubber grommets are pressed into
the radiator lower crossmember.
WARNING: THE AIR CONDITIONING SYSTEM (IF
EQUIPPED) IS UNDER A CONSTANT PRESSURE
EVEN WITH THE ENGINE OFF. REFER TO REFRIG-
ERANT WARNINGS IN, HEATING AND AIR CONDI-
TIONING BEFORE HANDLING ANY AIR
CONDITIONING COMPONENT.
NOTE: The radiator and radiator cooling fan can be
removed as an assembly. It is not necessary to
remove the cooling fan before removing or install-
ing the radiator.
(12) Disconnect the two high pressure fluid lines
at the hydraulic fan drive.
(13) Disconnect the low pressure return hose at
the hydraulic fan drive.
(14) Gently lift up and remove radiator from vehi-
cle. Be careful not to scrape the radiator fins against
any other component. Also be careful not to disturb
the air conditioning condenser (if equipped).
CLEANING
Clean radiator fins With the engine cold, apply cold
water and compressed air to the back (engine side) of
Fig. 32 Hose Clamp Tool - Typical
1 - HOSE CLAMP TOOL 6094
2 - HOSE CLAMP
Fig. 33 Clamp Number/Letter Location - Typical
1 - TYPICAL CONSTANT TENSION HOSE CLAMP
2 - CLAMP NUMBER/LETTER LOCATION
3 - TYPICAL HOSE
Fig. 34 Air Seals - Typical
1 - AIR DAM
2 - RADIATOR
3 - AIR DAM
4 - A/C CONDENSER
5 - AIR SEAL
WJENGINE 7 - 43
RADIATOR - 4.7L (Continued)

the radiator to flush the radiator and/or A/C con-
denser of debris.
INSPECTION
The radiator cooling fins should be checked for
damage or deterioration. Inspect cooling fins to make
sure they are not bent or crushed, these areas result
in reduced heat exchange causing the cooling system
to operate at higher temperatures. Inspect the plastic
end tanks for cracks, damage or leaks.
Inspect the radiator neck for damage or distortion.
INSTALLATION
CAUTION: Before installing the radiator or A/C con-
denser, be sure the radiator-to-body and radiator-to-
A/C condenser rubber air seals (Fig. 39) are
properly fastened to their original positions. These
are used at the top, bottom and sides of the radia-
tor and A/C condenser. To prevent overheating,
these seals must be installed to their original posi-
tions.
(1) Equipped with air conditioning: Gently lower
the radiator and fan shroud into the vehicle. Guide
the two radiator alignment dowels through the holes
in the rubber air seals first and then through the A/C
support brackets (Fig. 40). Continue to guide thealignment dowels into the rubber grommets located
in lower radiator crossmember. The holes in the
L-shaped brackets (located on bottom of A/C con-
denser) must be positioned between bottom of rubber
air seals and top of rubber grommets.
(2) Connect the radiator upper and lower hoses
and hose clamps to radiator.
CAUTION: The tangs on the hose clamps must be
positioned straight down.
(3) Install coolant reserve/overflow tank hose at
radiator.
(4) Connect both transmission cooler lines at the
radiator.
(5) Install both radiator mounting bolts.
(6) Install air inlet duct at grill.
(7) Attach electric connector for hydraulic fan con-
trol solenoid.
(8) Install the grill (Refer to 23 - BODY/EXTERI-
OR/GRILLE - INSTALLATION).
(9) Connect the two high pressure lines to the
hydraulic fan drive. Tighten
1¤2in. pressure line fit-
ting to 49 N´m (36 ft. lbs.). and the 3/8 in. pressure
line fitting to 29 N´m (21.5 ft. lbs.).
(10) Connect the low pressure hose to the hydrau-
lic fan drive. Position the spring clamp.
(11) Connect the power steering filter hoses to the
filter. Install new hose clamps.
(12) Rotate the fan blades (by hand) and check for
interference at fan shroud.
(13) Refill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(14) Refill the power steering reservoir and bleed
air from system (Refer to 19 - STEERING/PUMP -
STANDARD PROCEDURE).
(15) Connect battery cable at battery.
(16) Start and warm engine. Check for leaks.
RADIATOR - 4.0L
DESCRIPTION
All vehicles are equipped with a cross flow type
radiator with plastic side tanks (Fig. 36).
Plastic tanks, while stronger than brass, are sub-
ject to damage by impact, such as from tools or
wrenches. Handle radiator with care.
REMOVAL
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR. REFER TO COOLING SYSTEM DRAIN-
ING.
Fig. 35 Radiator Alignment Dowels - Typical
1 - RADIATOR
2 - ALIGNMENT DOWEL
3 - RADIATOR LOWER ISOLATOR
4 - RADIATOR LOWER CROSSMEMBER
7 - 44 ENGINEWJ
RADIATOR - 4.7L (Continued)

DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT START 1. Weak battery 1. Charge or replace as necessary.
2. Corroded or loose battery
connections.2. Clean and tighten battery
connections. Apply a coat of light
mineral grease to the terminals.
3. Faulty starter. 3. (Refer to 8 - ELECTRICAL/
STARTING - DIAGNOSIS AND
TESTING).
4. Faulty coil or control unit. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION COIL -
REMOVAL).
5. Incorrect spark plug gap. 5. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG -
CLEANING).
6. Dirt or water in fuel system. 6. Clean system and replace fuel filter.
7. Faulty fuel pump, relay or wiring. 7. Repair or replace as necessary.
ENGINE STALLS OR ROUGH
IDLE1. Idle speed set to low. 1. (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/IDLE AIR CONTROL
MOTOR - REMOVAL).
2. Idle mixture to lean or to rich. 2. Refer to Powertrain Diagnosis
Information.
3. Vacuum leak. 3. Inspect intake manifold and vacuum
hoses, repair or replace as necessary.
4. Faulty coil. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION COIL -
REMOVAL).
5. Incorrect engine timing. 5. (Refer to 9 - ENGINE/VALVE
TIMING - STANDARD PROCEDURE).
1. ENGINE LOSS OF POWER 1. Dirty or incorrectly gapped spark
plugs.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG -
CLEANING).
2. Dirt or water in fuel system. 2. Clean system and replace fuel filter.
3. Faulty fuel pump. 3. (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/FUEL PUMP - DIAGNOSIS
AND TESTING).
4. Blown cylinder head gasket. 4. Replace cylinder head gasket.
5. Low compression. 5. (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING), repair as necessary.
6. Burned, warped or pitted valves. 6. Replace as necessary.
7. Plugged or restricted exhaust
system.7. Inspect and replace as necessary.
8. Faulty coil. 8. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION COIL -
REMOVAL).
WJENGINE - 4.7L 9 - 65
ENGINE - 4.7L (Continued)

CONDITION POSSIBLE CAUSES CORRECTIONS
MAIN BEARING 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. Excessive end play. 5. Check thrust washers for wear.
6. Crankshaft journal out-of round. 6. Service or replace crankshaft.
7. Loose flywheel or torque
converter.7. Tighten to correct torque
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - LUBRICATION
CONDITION POSSIBLE CAUSES CORRECTION
OIL LEAKS 1. Gaskets and O-Rings. 1.
(a) Misaligned or damaged. (a) Replace as necessary.
(b) Loose fasteners, broken or
porous metal parts.(b) Tighten fasteners, Repair or
replace metal parts.
2. Crankshaft rear seal 2. Replace as necessary (Refer to 9 -
ENGINE/ENGINE BLOCK/
CRANKSHAFT OIL SEAL - REAR -
REMOVAL).
3. Crankshaft seal flange.
Scratched, nicked or grooved.3. Polish or replace crankshaft.
4. Oil pan flange cracked. 4. Replace oil pan (Refer to 9 -
ENGINE/LUBRICATION/OIL PAN -
REMOVAL).
5. Timing chain cover seal, damaged
or misaligned.5. Replace seal (Refer to 9 -
ENGINE/ENGINE BLOCK/
CRANKSHAFT OIL SEAL - FRONT -
REMOVAL).
6. Scratched or damaged vibration
damper hub.6. Polish or replace damper.
WJENGINE - 4.7L 9 - 67
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)

CYLINDER HEAD COVER(S) -
RIGHT
DESCRIPTION
The cylinder head covers are made of die cast mag-
nesium, and are not interchangeable from side-to-
side. It is imperative that nothing rest on the
cylinder head covers. Prolonged contact with other
items may wear a hole in the cylinder head cover.
REMOVAL - RIGHT SIDE
(1) Disconnect battery negative cable.
(2) Remove air cleaner assembly, resonator assem-
bly and air inlet hose.
(3) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(4) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(5) Remove air conditioning compressor retaining
bolts and move compressor to the left.
(6) Remove heater hoses.
(7) Disconnect injector and ignition coil connectors.
(8) Disconnect and remove positive crankcase ven-
tilation (PCV) hose.
(9) Remove oil fill tube.
(10) Un-clip injector and ignition coil harness and
move away from cylinder head cover.
(11) Remove right rear breather tube and filter
assembly.
(12) Remove cylinder head cover retaining bolts.
(13) Remove cylinder head cover.
NOTE: The gasket may be used again, provided no
cuts, tears, or deformation has occurred.
CLEANING
Clean cylinder head cover gasket surface.
Clean head rail, if necessary.
INSTALLATION - RIGHT SIDE
CAUTION: Do not use harsh cleaners to clean the
cylinder head covers. Severe damage to covers
may occur.
CAUTION: DO NOT allow other components includ-
ing the wire harness to rest on or against the
engine cylinder head cover. Prolonged contact with
other objects may wear a hole in the cylinder head
cover.
(1) Clean cylinder head cover and both sealing sur-
faces. Inspect and replace gasket as necessary.(2) Install cylinder head cover and hand start all
fasteners. Verify that all double ended studs are in
the correct location shown in (Fig. 38).
(3) Tighten cylinder head cover bolts and double
ended studs to 12 N´m (105 in. lbs).
(4) Install right rear breather tube and filter
assembly.
(5) Connect injector, ignition coil electrical connec-
tors and harness retaining clips.
(6) Install the oil fill tube.
(7) Install PCV hose.
(8) Install heater hoses.
(9) Install air conditioning compressor retaining
bolts.
(10) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(11) Fill Cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(12) Install air cleaner assembly, resonator assem-
bly and air inlet hose.
(13) Connect battery negative cable.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The valves are made of heat resistant steel and
have chrome plated stems to prevent scuffing. Each
valve is actuated by a roller rocker arm which pivots
on a stationary lash adjuster. All valves use three
bead lock keepers to retain the springs and promote
valve rotation.
Fig. 38 Cylinder Head CoverÐRight
ITEM DESCRIPTION TORQUE
1 Cover Fasteners 12 N´m (105 in. lbs.)
9 - 104 ENGINE - 4.7LWJ

free cloth to check that the bore is clean. Oil the
bores after cleaning to prevent rusting.
CLEANING
Thoroughly clean the oil pan and engine block gas-
ket surfaces.
Use compressed air to clean out:
²The galley at the oil filter adaptor hole.
²The front and rear oil galley holes.
²The feed holes for the crankshaft main bearings.
Once the block has been completely cleaned, apply
Loctite PST pipe sealant with Teflon 592 to the
threads of the front and rear oil galley plugs. Tighten
the plugs to 34 N´m (25 ft. lbs.) torque.
INSPECTION
(1) It is mandatory to use a dial bore gauge to
measure each cylinder bore diameter. To correctly
select the proper size piston, a cylinder bore gauge,
capable of reading in 0.003 mm (.0001 in.) INCRE-
MENTS is required. If a bore gauge is not available,
do not use an inside micrometer (Fig. 46).
(2) Measure the inside diameter of the cylinder
bore at three levels below top of bore. Start perpen-
dicular (across or at 90 degrees) to the axis of the
crankshaft and then take two additional reading.(3) Measure the cylinder bore diameter crosswise
to the cylinder block near the top of the bore. Repeat
the measurement near the middle of the bore, then
repeat the measurement near the bottom of the bore.
(4) Determine taper by subtracting the smaller
diameter from the larger diameter.
(5) Rotate measuring device 90É and repeat steps
above.
(6) Determine out-of-roundness by comparing the
difference between each measurement.
(7) If cylinder bore taper does not exceed 0.025
mm (0.001 inch) and out-of-roundness does not
exceed 0.025 mm (0.001 inch), the cylinder bore can
be honed. If the cylinder bore taper or out- of-round
condition exceeds these maximum limits, the cylinder
block must be replaced. A slight amount of taper
always exists in the cylinder bore after the engine
has been in use for a period of time.
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - CONNECTING ROD
BEARING FITTING
Inspect the connecting rod bearings for scoring and
bent alignment tabs (Fig. 47) (Fig. 48). Check the
bearings for normal wear patterns, scoring, grooving,
fatigue and pitting (Fig. 49). Replace any bearing
that shows abnormal wear.
Inspect the connecting rod journals for signs of
scoring, nicks and burrs.
Misaligned or bent connecting rods can cause
abnormal wear on pistons, piston rings, cylinder
walls, connecting rod bearings and crankshaft con-
necting rod journals. If wear patterns or damage to
any of these components indicate the probability of a
misaligned connecting rod, inspect it for correct rod
alignment. Replace misaligned, bent or twisted con-
necting rods.
(1) Wipe the oil from the connecting rod journal.
(2) Lubricate the upper bearing insert and install
in connecting rod.
(3) Use piston ring compressor and Guide Pins
Special Tool 8507 (Fig. 50) to install the rod and pis-
ton assemblies. The oil slinger slots in the rods must
face front of the engine. The ªFº's near the piston
wrist pin bore should point to the front of the engine.
(4) Install the lower bearing insert in the bearing
cap. The lower insert must be dry. Place strip of Plas-
tigage across full width of the lower insert at the cen-
ter of bearing cap. Plastigage must not crumble in
use. If brittle, obtain fresh stock.
(5) Install bearing cap and connecting rod on the
journal and tighten bolts to 27 N´m (20 ft. lbs.) plus a
90É turn. DO NOT rotate crankshaft. Plastigage will
smear, resulting in inaccurate indication.
Fig. 46 Bore GaugeÐTypical
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4-38MM
(1.5 in)
WJENGINE - 4.7L 9 - 109
ENGINE BLOCK (Continued)

ENGINE LUBRICATION FLOW CHARTÐBLOCK: TABLE 1
FROM TO
Oil Pickup Tube Oil Pump
Oil Pump Oil Filter
Oil Filter Block Main Oil Gallery
Block Main Oil Gallery 1. Crankshaft Main Journal
2. Left Cylinder Head*
3. Right Cylinder Head*
Crankshaft Main Journals Crankshaft Rod Journals
Crankshaft Number One Main Journal 1.Front Timing Chain Idler Shaft
2.Both Secondary Chain Tensioners
Left Cylinder Head See Table 2
Right Cylinder Head See Table 2
* The cylinder head
gaskets have an oil restricter to control oil flow to the cylinder heads.
ENGINE LUBRICATION FLOW CHARTÐCYLINDER HEADS: TABLE 2
FROM TO
Cylinder Head Oil Port (in bolt hole) Diagonal Cross Drilling to Main Oil Gallery
Main Oil Gallery (drilled through head from rear to
front)1. Base of Camshaft Towers
2. Lash Adjuster Towers
Base of Camshaft Towers Vertical Drilling Through Tower to Camshaft Bearings**
Lash Adjuster Towers Diagonal Drillings to Hydraulic Lash Adjuster Pockets
** The number three camshaft bearing journal feeds oil into the hollow camshaft tubes. Oil is routed to the intake
lobes, which have oil passages drilled into them to lubricate the rocker arms.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐENGINE OIL
PRESSURE
(1) Remove oil pressure sending unit (Fig. 89)and
install gauge assembly C-3292.
(2) Run engine until thermostat opens.
(3) Oil Pressure:
²Curb IdleÐ25 Kpa (4 psi) minimum
²3000 rpmÐ170 - 550 KPa (25 - 80 psi)
(4) If oil pressure is 0 at idle, shut off engine.
Check for a clogged oil pick-up screen or a pressure
relief valve stuck open.
DIAGNOSIS AND TESTINGÐREAR SEAL AREA
LEAKS
Since it is sometimes difficult to determine the
source of an oil leak in the rear seal area of the
engine, a more involved inspection is necessary. The
following steps should be followed to help pinpoint
the source of the leak.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. See Engine, for proper
repair procedures of these items.
(4) If no leaks are detected, pressurized the crank-
case as outlined in the section, Inspection (Engine oil
Leaks in general)
CAUTION: Do not exceed 20.6 kPa (3 psi).
9 - 128 ENGINE - 4.7LWJ
LUBRICATION (Continued)