2003 JEEP GRAND CHEROKEE 4.7 air filter

(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 or
scratches. The crankshaft seal flange is specially
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. (Refer to 9 - ENGINE - DIAGNOSIS AND
TESTING), under the Oil Leak row, for components
inspections on possible causes and corrections.
(7) After the oil leak root cause and appropriate
corrective action have been identified, (Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT OIL
SEAL - REAR - REMOVAL).
DIAGNOSIS AND TESTINGÐENGINE OIL LEAK
Begin with a thorough visual inspection of the
engine, particularly at the area of the suspected leak.If an oil leak source is not readily identifiable, the
following steps should be followed:
(1) Do not clean or degrease the engine at this
time because some solvents may cause rubber to
swell, temporarily stopping the leak.
(2) Add an oil soluble dye (use as recommended by
manufacturer). Start the engine and let idle for
approximately 15 minutes. Check the oil dipstick to
make sure the dye is thoroughly mixed as indicated
with a bright yellow color under a black light.
(3) Using a black light, inspect the entire engine
for fluorescent dye, particularly at the suspected area
of oil leak. If the oil leak is found and identified,
repair per service manual instructions.
(4) If dye is not observed, drive the vehicle at var-
ious speeds for approximately 24km (15 miles), and
repeat inspection.If the oil leak source is not pos-
itively identified at this time, proceed with the air
leak detection test method.
Air Leak Detection Test Method
(1) Disconnect the breather cap to air cleaner hose
at the breather cap end. Cap or plug breather cap
nipple.
(2) Remove the PCV valve from the cylinder head
cover. Cap or plug the PCV valve grommet.
(3) Attach an air hose with pressure gauge and
regulator to the dipstick tube.
CAUTION: Do not subject the engine assembly to
more than 20.6 kpa (3 PSI) of test pressure.
(4) Gradually apply air pressure from 1 psi to 2.5
psi maximum while applying soapy water at the sus-
pected source. Adjust the regulator to the suitable
test pressure that provide the best bubbles which
will pinpoint the leak source. If the oil leak is
detected and identified, repair per service manual
procedures.
(5) If the leakage occurs at the rear oil seal area,
refer to the section, Inspection for Rear Seal Area
Leak.
(6) If no leaks are detected, turn off the air supply
and remove the air hose and all plugs and caps.
Install the PCV valve and breather cap hose.
(7) Clean the oil off the suspect oil leak area using
a suitable solvent. Drive the vehicle at various
speeds approximately 24 km (15 miles). Inspect the
engine for signs of an oil leak by using a black light.
INSPECTION FOR REAR 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.
Fig. 89 Oil Pressure Sending Unit
1 - BELT
2 - OIL PRESSURE SENSOR
3 - OIL FILTER
4 - ELEC. CONNECTOR
WJENGINE - 4.7L 9 - 129
LUBRICATION (Continued)

(5) With a wiping cloth, clean the gasket sealing
surface of oil and grime.
INSTALLATION
(1) Lightly lubricate oil filter gasket with engine
oil.
(2) Thread filter onto adapter nipple. When gasket
makes contact with sealing surface, (Fig. 94)hand
tighten filter one full turn, do not over tighten.
(3) Add oil, verify crankcase oil level and start
engine. Inspect for oil leaks.
OIL PAN
DESCRIPTION
The engine oil pan is made of laminated steel and
has a single plane sealing surface. The sandwich
style oil pan gasket has an integrated windage tray
and steel carrier. The sealing area of the gasket is
molded with rubber and is designed to be reused as
long as the gasket is not cut, torn or ripped.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Raise vehicle on hoist.
(3) Remove structural cover (Refer to 9 - ENGINE/
ENGINE BLOCK/STRUCTURAL COVER - REMOV-
AL).
(4) Remove exhaust system Y-pipe.
(5) Remove starter (Refer to 8 - ELECTRICAL/
STARTING/STARTER MOTOR - REMOVAL).
(6) Drain engine oil.
(7) Un-clip transmission lines from support on oil
pan stud. Move lines for oil pan clearance.
CAUTION: DO NOT pry on the oil pan gasket when
removing the oil pan, The oil pan gasket is mounted
to the cylinder block in three locations and will
remain attached to block when lowering oil pan.
Gasket can not be removed with oil pan.
(8) Remove oil pan bolts and oil pan.
(9) Remove oil pump pickup tube.
(10) Remove oil pan gasket.
CLEANING
(1) Clean oil pan in solvent and wipe dry with a
clean cloth.
(2) Clean the oil pan gasket surface.DO NOTuse
a grinder wheel or other abrasive tool to clean seal-
ing surface.
(3) Clean oil screen and tube thoroughly in clean
solvent.
INSPECTION
(1) Inspect oil drain plug and plug hole for
stripped or damaged threads. Repair as necessary.
(2) Inspect the oil pan mounting flange for bends
or distortion. Straighten flange, if necessary.
INSTALLATION
(1) Clean oil pan and all sealing surfaces. Inspect
oil pan gasket and replace as necessary.
(2) Install oil pan gasket.
Fig. 93 Oil Filter - 4.7L Engine
1 - ENGINE OIL FILTER
Fig. 94 Oil Filter Sealing SurfaceÐTypical
1 - SEALING SURFACE
2 - RUBBER GASKET
3 - OIL FILTER
9 - 132 ENGINE - 4.7LWJ
OIL FILTER (Continued)

(8) Connect fuel return and pressure lines to fuel
pump module fittings (Fig. 16). Refer to Quick-Con-
nect Fittings.
(9) Install fuel tank. Refer to Fuel Tank Installa-
tion.
FUEL RAIL
DESCRIPTION
DESCRIPTION - 4.7L
The fuel injector rail is used to mount the fuel
injectors to the engine. It is mounted to the intake
manifold (Fig. 20).
DESCRIPTION - 4.0L
The fuel injector rail is used to mount the fuel
injectors to the engine (Fig. 21). On the 4.0L 6±cylin-
der engine, afuel damperis located near the center
of the fuel rail (Fig. 21).
OPERATION
OPERATION - 4.7L
High pressure fuel from the fuel pump is routed to
the fuel rail. The fuel rail then supplies the neces-
sary fuel to each individual fuel injector.
A fuel pressure test port is located on the fuel rail
(Fig. 20). A quick-connect fitting with a safety latch
is used to attach the fuel line to the fuel rail.
The fuel rail is not repairable.
OPERATION - 4.0L
The fuel injector rail supplies the necessary fuel to
each individual fuel injector.
High pressure fuel from the fuel pump is routed to
the fuel rail. The fuel rail then supplies the neces-
sary fuel to each individual fuel injector.
The fuel damper is used only to help control fuel
pressure pulsations. These pulsations are the result
of the firing of the fuel injectors. It isnot usedas a
fuel pressure regulator. The fuel pressure regulator is
not mountedto the fuel rail on any engine. It is
located near the front of the fuel tank above the rear
axle. Refer to Fuel Filter/Fuel Pressure Regulator in
this group for information.
A fuel pressure test port is located on the fuel rail
(Fig. 21). A quick-connect fitting with a safety latch
is used to attach the fuel line to the fuel rail.
The fuel rail is not repairable.
REMOVAL
REMOVAL - 4.7L
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT PRESSURE EVEN WITH ENGINE OFF.
BEFORE SERVICING FUEL RAIL, FUEL SYSTEM
PRESSURE MUST BE RELEASED.
Fig. 20 Fuel Injector RailÐ4.7L V-8 Engine
1 - MOUNTING BOLTS (4)
2 - INJ.#7
3 - INJ.#5
4 - QUICK-CONNECT FITTING
5 - INJ.#3
6 - FUEL INJECTOR RAIL
7 - INJ.#1
8 - CONNECTOR TUBE
9 - INJ.#2
10 - INJ.#4
11 - INJ.#6
12 - INJ.#8
13 - PRESSURE TEST PORT CAP
WJFUEL DELIVERY 14 - 15
FUEL PUMP MODULE (Continued)

NOTE: The evaporative system uses specially man-
ufactured lines/hoses. If replacement becomes nec-
essary, only use fuel resistant, low permeation
hose.
Certain components can be found in (Fig. 1).
DESCRIPTION - CCV SYSTEM
The 4.0L 6±cylinder engine is equipped with a
Crankcase Ventilation (CCV) system. The system
consists of:
²A fixed orifice fitting of a calibrated size. This
fitting is pressed into a rubber grommet located on
the top/rear of cylinder head (valve) cover (Fig. 2).
²a pair of breather tubes (lines) to connect the
system components.
²the air cleaner housing.
²an air inlet fitting (Fig. 2).
DESCRIPTION - PCV SYSTEM
The 4.7L V-8 engine is equipped with a closed
crankcase ventilation system and a Positive Crank-
case Ventilation (PCV) valve.
This system consists of:
Fig. 1 ORVR / LDP COMPONENTS
1 - FUEL TANK (LEFT SIDE) 6 - EVAP CANISTER
2 - FRAME RAIL (LEFT-REAR OUTSIDE) 7 - LDP FILTER
3 - FUEL VENT TUBE 8 - TWO-PIECE SUPPORT BRACKET
4 - FUEL FILL TUBE 9 - LEAK DETECTION PUMP (LDP)
5 - CONTROL VALVE
Fig. 2 CCV SystemÐ4.0L Engine
1 - AIR INLET FITTING
2 - FIXED ORIFICE FITTING
3 - CCV BREATHER TUBE (REAR)
4 - INT. MAN. FITTING
5 - CCV BREATHER TUBE (FRONT)
WJEVAPORATIVE EMISSIONS 25 - 25
EVAPORATIVE EMISSIONS (Continued)

²a PCV valve mounted to the oil filler housing
(Fig. 3). The PCV valve is sealed to the oil filler
housing with an o-ring.
²the air cleaner housing
²two interconnected breathers threaded into the
rear of each cylinder head (Fig. 4).
²tubes and hose to connect the system compo-
nents.
OPERATION
OPERATION - 4.0L CCV SYSTEM
The CCV system performs the same function as a
conventional PCV system, but does not use a vacuum
controlled PCV valve.
The fixed orifice fitting meters the amount of
crankcase vapors drawn out of the engine.
When the engine is operating, fresh air enters the
engine and mixes with crankcase vapors. Engine vac-uum draws the vapor/air mixture through the fixed
orifice and into the intake manifold. The vapors are
then consumed during engine combustion.
OPERATION - 4.7L PCV SYSTEM
The PCV system operates by engine intake mani-
fold vacuum. Filtered air is routed into the crankcase
through the air cleaner hose and crankcase breath-
ers. The metered air, along with crankcase vapors,
are drawn through the PCV valve and into a passage
in the intake manifold. The PCV system manages
crankcase pressure and meters blow-by gases to the
intake system, reducing engine sludge formation.
The PCV valve contains a spring loaded plunger.
This plunger meters the amount of crankcase vapors
routed into the combustion chamber based on intake
manifold vacuum.
TYPICALPCV valves are shown in (Fig. 5), (Fig.
6) and (Fig. 7).
When the engine is not operating, or during an
engine pop-back, the spring forces the plunger back
against the seat (Fig. 5). This will prevent vapors
from flowing through the valve.
Fig. 3 PCV Valve/Oil Filler Tube (Housing)Ð4.7L
Engine
1 - O-RING
2 - LOCATING TABS
3 - CAM LOCK
4 - OIL FILLER TUBE
5 - PCV LINE/HOSE
6 - P C V VA LV E
Fig. 4 PCV System Hoses/TubesÐ4.7L Engine
1 - FRESH AIR FITTING
2 - CONNECTING TUBES/HOSES
3 - CRANKCASE BREATHERS (2)
4 - RUBBER HOSE
5 - AIR CLEANER RESONATOR
25 - 26 EVAPORATIVE EMISSIONSWJ
EVAPORATIVE EMISSIONS (Continued)

Check the vapor/vacuum lines at the LDP, LDP
filter and EVAP canister purge solenoid for
damage or leaks. If a leak is present, a Diagnos-
tic Trouble Code (DTC) may be set.
(2) Connect electrical connector to LDP.
(3) While raising front section of support bracket,
connect LDP wiring clip (Fig. 20).
(4) Install 3 LDP mounting bolts (Fig. 19). Refer to
Torque Specifications.
(5) Join front and rear sections of two-piece sup-
port bracket by installing 3 bolts on bottom of sup-
port bracket (Fig. 17). Do not tighten bolts at this
time.
(6) Install support bracket brace bolt (Fig. 17). Do
not tighten bolt at this time.
(7) Tighten 2 support bracket nuts at frame rail
(Fig. 19). Refer to Torque Specifications.
(8) Tighten 3 support bracket bolts and brace bolt.
Refer to Torque Specifications.
(9) Position stone shield behind left/rear wheel
(Fig. 18). Install new plastic rivets.
ORVR
DESCRIPTION
The ORVR (On-Board Refueling Vapor Recovery)
system consists of a unique fuel tank, flow manage-
ment valve, fluid control valve, one-way check valve
and vapor canister. Certain ORVR components can be
found in (Fig. 1).
OPERATION
The ORVR (On-Board Refueling Vapor Recovery)
system is used to remove excess fuel tank vapors.
This is done while the vehicle is being refueled. Cer-
tain ORVR components can be found in (Fig. 1).
Fuel flowing into the fuel filler tube (approx. 1º
I.D.) creates an aspiration effect drawing air into the
fuel fill tube. During refueling, the fuel tank is
vented to the EVAP canister to capture escaping
vapors. With air flowing into the filler tube, there are
no fuel vapors escaping to the atmosphere. Once the
refueling vapors are captured by the EVAP canister,
the vehicle's computer controlled purge system draws
vapor out of the canister for the engine to burn. The
vapor flow is metered by the purge solenoid so that
there is no, or minimal impact on driveability or
tailpipe emissions.As fuel starts to flow through the fuel fill tube, it
opens the normally closed check valve and enters the
fuel tank. Vapor or air is expelled from the tank
through the control valve and on to the vapor canis-
ter. Vapor is absorbed in the EVAP canister until
vapor flow in the lines stops. This stoppage occurs
following fuel shut-off, or by having the fuel level in
the tank rise high enough to close the control valve.
This control valve contains a float that rises to seal
the large diameter vent path to the EVAP canister.
At this point in the refueling process, fuel tank pres-
sure increases, the check valve closes (preventing liq-
uid fuel from spiting back at the operator), and fuel
then rises up the fuel filler tube to shut off the dis-
pensing nozzle.
PCV VALVE
DIAGNOSIS AND TESTING - PCV VALVE/PCV
SYSTEM - 4.7L
(1) Disconnect PCV line/hose (Fig. 21) by discon-
necting rubber connecting hose at PCV valve fitting.
(2) Remove PCV valve at oil filler tube by rotating
PCV valve downward until locating tabs have been
freed at cam lock (Fig. 21). After tabs have cleared,
pull valve straight out from filler tube.To prevent
damage to PCV valve locating tabs, valve must
be pointed downward for removal. Do not force
valve from oil filler tube.
(3) After valve is removed, check condition of valve
o-ring (Fig. 21). Also, PCV valve should rattle when
shaken.
(4) Reconnect PCV valve to its connecting line/
hose.
(5) Start engine and bring to idle speed.
(6) If valve is not plugged, a hissing noise will be
heard as air passes through valve. Also, a strong vac-
uum should be felt with a finger placed at valve
inlet.
(7) If vacuum is not felt at valve inlet, check line/
hose for kinks or for obstruction. If necessary, clean
out intake manifold fitting at rear of manifold. Do
this by turning a 1/4 inch drill (by hand) through the
fitting to dislodge any solid particles. Blow out the
fitting with shop air. If necessary, use a smaller drill
to avoid removing any metal from the fitting.
WJEVAPORATIVE EMISSIONS 25 - 37
LEAK DETECTION PUMP (Continued)