1995 JEEP CHEROKEE spark plug

ANTENNA
All models use a fixed-length stainless steel rod-
type antenna mast, installed at the right front (fend-
er on XJ, cowl side on YJ) of the vehicle. The
antenna mast is connected to the center wire of the
coaxial antenna cable and is not grounded to any
part of the vehicle.
To eliminate static, the antenna base must have a
good ground. The coaxial antenna cable shield (the
outer wire mesh of the cable) is grounded to the an-
tenna base and the radio chassis.
The factory installed ETRs automatically compen-
sate for radio antenna trim. Therefore, no antenna
trimmer adjustment is required or possible when re-
placing the receiver or the antenna.
RADIO NOISE SUPPRESSION
Radio Frequency Interference (RFI) and Electro-
Magnetic Interference (EMI) noise suppression is ac-
complished primarily through circuitry internal to
the radio receivers. These internal suppression de-
vices are only serviced as a part of the radio receiver.External suppression devices that are serviceable
and should be checked in the case of RFI or EMI
noise complaints include the following:
²radio antenna base ground
²engine-to-body ground strap
²resistor-type spark plugs
²radio suppression-type secondary ignition wiring.
In addition, if the source of RFI or EMI noise is
identified as a component on the vehicle (i.e.:genera-
tor, blower motor, etc.), the ground path for that com-
ponent should be checked. If excessive resistance is
found in that circuit, repair as required before con-
sidering any component replacement.
Fleet vehicles are available with an extra-cost RFI-
suppressed Powertrain Control Module (PCM). This
unit reduces interference generated by the PCM on
some radio frequencies used in two-way radio com-
munications. However, this unit will not resolve com-
plaints of RFI in the commercial AM or FM radio
frequency ranges.
DIAGNOSIS
RADIO
CAUTION: Do not operate the radio with speaker
leads detached since damage to the transistors
may result.
(1) Check fuse 2 in fuseblock module and fuse in
back of radio chassis. If OK, go to next step. If not
OK, replace fuse.
(2) Turn ignition switch to ON position. Check for
battery voltage at fuse 2. If OK, go to next step. If
not OK, repair circuit to ignition switch as required.
(3) Turn ignition switch to OFF position. Discon-
nect battery negative cable. Remove instrument clus-
ter bezel. Remove radio, but do not unplug any
connections. Check for continuity between the radio
chassis and a good ground. There should be continu-
ity. If OK, go to next step. If not OK, repair radio
ground circuit as required.
(4) Connect battery negative cable. Turn ignition
switch to ON position. See Radio Connections chart.
Check for battery voltage at cavity 3 of radio connec-
tor. If OK, go to next step. If not OK, repair circuit to
fuse 2 as required.
(5) Turn ignition switch to OFF position. Check for
battery voltage at cavity 4 of radio connector. If OK,
replace radio. If not OK, repair circuit to IOD fuse in
PDC as required.
SPEAKERS
CAUTION: Do not operate the radio with speaker
leads detached since damage to the transistors
may result.
(1) Turn radio on and adjust balance and fader
controls to check performance of each individual
speaker. Note the speaker locations that are not per-
forming correctly. Go to next step.
(2) Turn radio off. Disconnect battery negative ca-
ble. Remove instrument cluster bezel and remove ra-
dio. See Radio Connections chart. Check both the
speaker feed and return cavities at radio for continu-
ity to a good ground. There should be no continuity.
If OK, go to next step. If not OK, repair wiring cir-
cuit as required.
(3) Check resistance between speaker feed and re-
turn cavities. Meter should read between 3 and 8
ohms (speaker impedance). If OK, see diagnosis for
Radio. If not OK, go to next step.
(4) Unplug speaker wiring connector. Check for
continuity between speaker feed cavity at radio and
at speaker. Repeat check between speaker return
cavity at radio and at speaker. If OK, replace
speaker. If not OK, repair wiring circuit as required.
8F - 2 AUDIO SYSTEMSJ

(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. Check as follows:
(a) On YJ models, it is grounded at all times.
There should be continuity to ground at cavity for
relay terminal 85 at all times. If not, repair circuit
to ground as required.
(b) On XJ models, it is energized when the head-
lamp switch is on. There should be battery voltage
at cavity for relay terminal 85 with the headlamp
switch on. If not, repair circuit to headlamp switch
as required.
ANTENNA
The following four tests are used to diagnose the
antenna with an ohmmeter:
²mast to ground test (Test 1)
²tip-of-mast to tip-of-conductor test (Test 2)
²body ground to battery ground test (Test 3)
²body ground to coaxial shield test (Test 4).
Ohmmeter test lead connections for each test are
shown in Figure 3.
TEST 1
Test 1 determines if the antenna mast is insulated
from the base. Proceed as follows:
(1) Disconnect antenna cable lead from radio chas-
sis and isolate.
(2) Connect one ohmmeter lead to tip of antenna
mast and the other lead to the antenna base. Check
for continuity.
(3) There should be no continuity. If continuity is
found, replace defective or damaged antenna base
and cable assembly.
TEST 2
Test 2 checks the antenna for an open circuit as fol-
lows:
(1) Disconnect the antenna cable lead from the ra-
dio chassis.
(2) Connect one ohmmeter test lead to tip of an-
tenna mast. Connect remaining lead to tip of an-
tenna cable lead (the part inserted into the radio).
(3) Continuity should exist (ohmmeter should only
register a fraction of an ohm). High or infinite resis-
tance indicates damage to the base and cable assem-
bly. Replace if required.
TEST 3
Test 3 checks condition of the vehicle body ground
connection as follows:
(1) Connect one ohmmeter test lead to the vehicle
fender and the other lead to the battery negative
post.
(2) Resistance should be less than one ohm.
(3) If resistance is more than one ohm, check the
braided ground strap connected to the engine and ve-
hicle body for being loose, corroded, or damaged. Re-
pair as necessary.
TEST 4
Test 4 checks condition of the ground between the
antenna base and vehicle body as follows:
(1) Connect one ohmmeter test lead to the fender
and the other lead to the crimp on the coaxial an-
tenna cable shield.
(2) Resistance should be less then one ohm.
(3) If resistance is more then one ohm:
(a) On YJ models, replace the antenna base at-
taching screws with new cadmium plated screws.
(b) On XJ models, clean and/or tighten antenna
base to fender mounting hardware.
RADIO FREQUENCY INTERFERENCE
Inspect ground connections at:
²blower motor
²electric fuel pump
²generator
²ignition module
²wiper motor
²antenna coaxial ground
²radio ground
²body-to-engine ground strap (braided).
Clean, tighten or repair as required.
Also inspect the following secondary ignition sys-
tem components:
²spark plug wire routing and condition
²distributor cap and rotor
²ignition coil
²spark plugs.
Reroute spark plug wires or replace components as
required.
Fig. 3 Antenna Tests
JAUDIO SYSTEMS 8F - 5

the airbag cushion so it can discharge the gas it pro-
duces directly into the cushion. The protective cover
is fitted to the front of the airbag module and forms
a decorative cover in the center of the steering wheel.
Upon airbag deployment, this cover will split hori-
zontally.
STORAGE
The airbag module must be stored in its original,
special container until used for service. Also, it must
be stored in a clean, dry environment; away from
sources of extreme heat, sparks, and high electrical
energy. Always place or store the module on a surface
with the trim cover facing up to minimize movement
in case of accidental deployment.
IMPACT SENSOR/INFLATOR ASSEMBLY
The impact sensor/inflator assembly is mounted to
the back of the airbag module. It seals the hole in
the steering wheel side of the airbag cushion so that
gas produced in the inflator can be discharged di-
rectly into the cushion.
The impact sensor provides verification of the di-
rection and severity of the impact. A spherical sens-
ing mass housed in a cylinder will move forward and
rotate a D-shaft when the vehicle is subjected to a
frontal impact of sufficient severity. Airbag inflation
is designed to occur at a precisely calibrated vehicle
deceleration force, and is not linked to vehicle road
speed.The D-shaft retains two spring-loaded firing pins.
When a firing pin is released by the D-shaft, it
strikes and ignites a primer. The primer then reacts
with the pelletized, solid generant contained in the
inflator to produce the nitrogen gas that inflates the
airbag cushion.
ARMING/DISARMING MECHANISM
The steering wheel hub incorporates an airbag
arming/disarming mechanism and a specially de-
signed nut-blocker. The nut-blocker serves as a safety
to prevent removal of the airbag module until the
unit has been disarmed. A removable plastic cover
plug on the top, outer hub of the steering wheel al-
lows access to the arming screw.
When the airbag module is disarmed, the arming
screw extends upward from the steering wheel hub.
This will prevent installation of the plastic cover
plug. Also, the nut-blocker is retracted to allow ac-
cess to the two upper airbag module mounting nuts.
When the airbag module is armed, the plastic cover
plug will install flush with the outer surface of the
steering wheel hub. In addition, the nut-blocker will
prevent access to the two upper airbag module
mounting nuts.
DIAGNOSIS
This mechanical airbag system can not be diag-
nosed or repaired. The only serviced component is
the airbag module assembly. If the airbag module isdamaged in any way or deployed, it must be re-
placed.
SERVICE PROCEDURES
AIRBAG SYSTEM SERVICE (DEPLOYED)
Any vehicle which is to be returned to use after an
airbag deployment, must have the airbag module re-
placed. This is a one-time component and cannot be
reused.
AIRBAG MODULE HANDLING
UNDEPLOYED
At no time should any source of electricity be per-
mitted near the inflator on the back of the module.
When carrying an undeployed module, the trim cover
should be pointed away from the body to minimizeinjury in the event of accidental deployment. If the
module is placed on a bench or other surface, the
plastic trim cover should be face up to minimize
movement in case of accidental deployment.
In addition, the airbag module should be disarmed
whenever the steering wheel or steering column re-
quires service or removal. Failure to observe this
warning could result in accidental airbag deployment
and possible personal injury. Refer to Group 19 -
Steering for more service procedures on steering
wheel and steering column.
8M - 2 RESTRAINT SYSTEMSJ

minutes). The use of a locating dowel is recom-
mended during assembly to prevent smearing the
material off location.
Mopar Gasket Maker should be applied sparingly
to one gasket surface. The sealant diameter should
be 1.00 mm (0.04 inch) or less. Be certain the mate-
rial surrounds each mounting hole. Excess material
can easily be wiped off. Components should be
torqued in place within 15 minutes. The use of a lo-
cating dowel is recommended during assembly to pre-
vent smearing the material off location.
ENGINE PERFORMANCE
To provide best vehicle performance and lowest ve-
hicle emissions, it is most important that the tune-up
be done accurately. Use the specifications listed on
the Vehicle Emission Control Information label found
on the engine compartment hood.
(1) Test battery specific gravity. Add water, if nec-
essary. Clean and tighten battery connections.
(2) Test cranking amperage draw (refer to Group
8B, Battery/Starter Service for the proper proce-
dures).
(3) Tighten the intake manifold bolts (refer to
Group 11, Exhaust System and Intake Manifold for
the proper specifications).
(4) Perform cylinder compression test:
(a) Check engine oil level and add oil, if neces-
sary.
(b) Drive the vehicle until engine reaches normal
operating temperature.
(c) Select a route free from traffic and other
forms of congestion, observe all traffic laws and
briskly accelerate through the gears several times.
The higher engine speed may help clean out valve
seat deposits which can prevent accurate compres-
sion readings.
CAUTION: DO NOT overspeed the engine.
(d) Remove all spark plugs from engine. As spark
plugs are being removed, check electrodes for ab-
normal firing indicatorsÐfouled, hot, oily, etc.
Record cylinder number of spark plug for future
reference.
(e) Disconnect coil wire from distributor and se-
cure to good ground to prevent a spark from start-
ing a fire.
(f) Be sure throttle blades are fully open during
the compression check.
(g) Insert compression gage adaptor into the
No.1 spark plug hole. Crank engine until maximum
pressure is reached on gauge. Record this pressure
as No.1 cylinder pressure.
(h) Repeat Step 4g for all remaining cylinders.
(i) Compression should not be less than 689 kPa
(100 psi) and not vary more than 172 kPa (25 psi)
from cylinder to cylinder.(j) If cylinder(s) have abnormally low compres-
sion pressures, repeat steps 4a through 4h.
(k) If the same cylinder(s) repeat an abnormally
low reading, it could indicate the existence of a
problem in the cylinder.
The recommended compression pressures are
to be used only as a guide to diagnosing engine
problems. An engine should NOT be disassem-
bled to determine the cause of low compression
unless some malfunction is present.
(5) Clean or replace spark plugs as necessary. Ad-
just gap (refer to Group 8D, Ignition System for gap
adjustment and torque).
(6) Test resistance of spark plug cables (refer to
Group 8D, Ignition System).
(7) Inspect the primary wire. Test coil output volt-
age, primary and secondary resistance. Replace parts
as necessary (refer to Group 8D, Ignition System and
make necessary adjustment).
(8) Perform a combustion analysis.
(9) Test fuel pump for pressure (refer to Group 14,
Fuel System for the proper specifications).
(10) Inspect air filter element (refer to Group 0,
Lubrication and Maintenance for the proper proce-
dure).
(11) Inspect crankcase ventilation system (refer to
Group 0, Lubrication and Maintenance for the proper
procedure).
(12) For emission controls refer to Group 25, Emis-
sion Controls System for service procedures.
(13) Inspect and adjust accessory belt drives (refer
to Group 7, Cooling System for the proper adjust-
ments).
(14) Road test vehicle as a final test.
HONING CYLINDER BORES
Before honing, stuff plenty of clean shop towels un-
der the bores and over the crankshaft to keep abra-
sive materials from entering the crankshaft area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823 equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). 20-60 strokes, de-
pending on the bore condition, will be sufficient to
provide a satisfactory surface. Using honing oil
C-3501-3880 or a light honing oil available from ma-
jor oil distributors.
9 - 2 ENGINESJ

CONNECTING ROD BEARING CLEARANCE
Engine connecting rod bearing clearances can be
determined by use of Plastigage, or equivalent. The
following is the recommended procedures for the use
of Plastigage:
(1) Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(2) Place a piece of Plastigage across the entire width
of the bearing cap shell (Fig. 2). Position the Plastigage
approximately 6.35 mm (1/4 inch) off center and away
from the oil holes. In addition, suspect areas can be
checked by placing the Plastigage in the suspect area.
(3) The crankshaft must be turned until the connect-
ing rod to be checked starts moving toward the top of
the engine. Only then should the rod cap with Plasti-
gage in place be assembled. Tighten the rod cap nut to
45 Nzm (33 ft. lbs.) torque.DO NOT rotate the crank-
shaft or the Plastigage may be smeared, giving in-
accurate results.
(4) Remove the bearing cap and compare the width
of the flattened Plastigage with the scale provided on
the package (Fig. 3). Plastigage generally comes in 2
scales (one scale is in inches and the other is a met-
ric scale). Locate the band closest to the same width.
This band shows the amount of clearance. Differ-
ences in readings between the ends indicate the
amount of taper present. Record all readings taken
(refer to Engine Specifications).
(5) Plastigage is available in a variety of clearance
ranges. The 0.025-0.076 mm (0.001-0.003 inch) range
is usually the most appropriate for checking engine
bearing clearances.
REPAIR DAMAGED OR WORN THREADS
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.
This brings the hole back to its original thread
size.
CAUTION: Be sure that the tapped holes maintain
the original center line.Heli-Coil tools and inserts are readily available
from automotive parts jobbers.
SERVICE ENGINE ASSEMBLY (SHORT BLOCK)
A service replacement engine assembly (short
block) may be installed whenever the original cylin-
der block is defective or damaged beyond repair. It
consists of the cylinder block, crankshaft, piston and
rod assemblies. If needed, the camshaft must be pro-
cured separately and installed before the engine is
installed in the vehicle.
A short block is identified with the letter ``S'' stamped
on the same machined surface where the build date
code is stamped for complete engine assemblies.
Installation includes the transfer of components
from the defective or damaged original engine. Fol-
low the appropriate procedures for cleaning, inspec-
tion and torque tightening.
HYDROSTATIC LOCK
When an engine is suspected of hydrostatic lock
(regardless of what caused the problem), follow the
steps below.
(1) Perform the Fuel Pressure Release Procedure
(refer to Group 14, Fuel System).
(2) Disconnect the negative cable from the battery.
(3) Inspect air cleaner, induction system and in-
take manifold to ensure system is dry and clear of
foreign material.
(4) Place a shop towel around the spark plugs to
catch any fluid that may possibly be under pressure in
the cylinder head. Remove the plugs from the engine.
CAUTION: DO NOT use the starter motor to rotate
the crankshaft. Severe damage could occur.
(5) With all spark plugs removed, rotate the crank-
shaft using a breaker bar and socket.
(6) Identify the fluid in the cylinders (i.e. coolant,
fuel, oil, etc.).
(7) Make sure all fluid has been removed from the
cylinders.
(8) Repair engine or components as necessary to
prevent this problem from occurring again.
(9) Squirt engine oil into the cylinders to lubricate
the walls. This will prevent damage on restart.
(10) Install new spark plugs. Tighten the spark
plugs to 37 Nzm (27 ft. lbs.) torque.
(11) Drain engine oil. Remove and discard the oil
filter.
(12) Install the drain plug. Tighten the plug to 34
Nzm (25 ft. lbs.) torque.
(13) Install a new oil filter.
(14) Fill engine crankcase with the specified
amount and grade of oil (refer to Group 0, Lubrica-
tion and Maintenance).
(15) Connect the negative cable to the battery.
(16) Start the engine and check for any leaks.
Fig. 3 Clearance Measurement
9 - 4 ENGINESJ

ENGINE DIAGNOSIS
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine tune-ups.
These malfunctions may be classified as either per-
formance (e.g., engine idles rough and stalls) or me-
chanical (e.g., a strange noise).
Refer to the Service DiagnosisÐPerformance chart
and the Service DiagnosisÐMechanical chart for pos-
sible causes and corrections of malfunctions. Refer to
Group 14, Fuel System for the fuel system diagnosis.
GENERAL INFORMATION
Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can
not be isolated with the Service Diagnosis charts. In-
formation concerning additional tests and diagnosis
is provided within the following diagnosis:
²Cylinder Compression Pressure Test.
²Cylinder Combustion Pressure Leakage Test.
²Engine Cylinder Head Gasket Failure Diagnosis.
²Intake Manifold Leakage Diagnosis.
INTAKE MANIFOLD LEAKAGE DIAGNOSIS
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
METHOD 1
(1) Start the engine.
(2) Spray a small stream of water at the suspected
leak area.
(3) If a change in RPM'S, the area of the suspected
leak has been found.
(4) Repair as required.
CYLINDER COMPRESSION PRESSURE TEST
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) Disconnect the ignition coil.(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the 3rd
revolution. Continue the test for the remaining cylin-
ders.
Refer to Engine Specifications for the correct en-
gine compression pressures.
ENGINE CYLINDER HEAD GASKET FAILURE
DIAGNOSIS
A leaking engine cylinder head gasket usually re-
sults in loss of power, loss of coolant and engine mis-
firing.
An engine cylinder head gasket leak can be located
between adjacent cylinders or between a cylinder and
the adjacent water jacket.
²An engine cylinder head gasket leaking between
adjacent cylinders is indicated by a loss of power
and/or engine misfire.
²An engine cylinder head gasket leaking between a
cylinder and an adjacent water jacket is indicated by
coolant foaming or overheating and loss of coolant.
CYLINDER-TO-CYLINDER LEAKAGE TEST
To determine if an engine cylinder head gasket is
leaking between adjacent cylinders; follow the proce-
dures outlined in Cylinder Compression Pressure
Test. An engine cylinder head gasket leaking between
adjacent 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. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
Remove the radiator cap.
Start the engine and allow it to warm up until the
engine thermostat opens.
If a large combustion/compression pressure leak ex-
ists, bubbles will be visible in the coolant.
If bubbles are not visible, install a radiator pres-
sure tester and pressurize the coolant system.
If a cylinder is leaking combustion pressure into
the water jacket, the tester pointer will pulsate with
every combustion stroke of the cylinder.
JENGINES 9 - 5

CYLINDER COMBUSTION PRESSURE LEAKAGE
TEST
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing).
²Leaks between adjacent cylinders or into water
jacket.
²Any causes for combustion/compression pressure
loss.
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn the engine
OFF.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1 379
kPa (200 psi) maximum and 552 kPa (80 psi) recom-
mended.
Perform the test procedures on each cylinder ac-
cording to the tester manufacturer's instructions.
While testing, listen for pressurized air escaping
through the throttle body, tailpipe and oil filler cap
opening. Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
Refer to the Cylinder Combustion Pressure Leak-
age Test Diagnosis chart.
INSPECTION (ENGINE OIL LEAKS IN GENERAL)
Begin with a through visual inspection of the en-
gine, particularly at the area of the suspected leak. If
an oil leak source is not readily identifiable, the fol-
lowing 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 ap-
proximately 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, re-
pair per service manual instructions.
(4) If dye is not observed, drive the vehicle at var-
ious speeds for approximately 24km (15 miles), and
repeat step (3).
If the oil leak source is not positively identi-
fied at this time, proceed with the air leak detec-
tion test method as follows:
(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 de-
tected and identified, repair per service manual pro-
cedures.
(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. In-
stall the PCV valve and breather cap hose. Proceed
to step 7.
(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 en-
gine, a more involved inspection is necessary. The fol-
lowing 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
9 - 6 ENGINESJ

(3) Connect the CCV hoses (Fig. 1).
(4) Connect negative cable to battery.
VALVE COMPONENT REPLACEÐCYLINDER HEAD
NOT REMOVED
ROCKER ARMS AND PUSH RODS
This procedure can be done with the engine in or
out of the vehicle.
REMOVAL
(1) Remove the engine cylinder head cover.
(2) Remove the capscrews at each bridge and pivot
assembly (Fig. 2). Alternately loosen the capscrews
one turn at a time to avoid damaging the bridges.
(3) Check for rocker arm bridges which are causing
misalignment of the rocker arm to valve tip area.
(4) Remove the bridges, pivots and corresponding
pairs of rocker arms (Fig. 2). Place them on a bench
in the same order as removed.
(5) Remove the push rods and place them on a
bench in the same order as removed.
CLEANING
Clean all the components with cleaning solvent.
Use compressed air to blow out the oil passages in
the rocker arms and push rods.
INSPECTION
Inspect the pivot surface area of each rocker arm.
Replace any that are scuffed, pitted, cracked or ex-
cessively worn.
Inspect the valve stem tip contact surface of each
rocker arm and replace any rocker arm that is deeply
pitted.Inspect each push rod end for excessive wear and
replace as required. If any push rod is excessively
worn because of lack of oil, replace it and inspect the
corresponding hydraulic tappet for excessive wear.
Inspect the push rods for straightness by rolling
them on a flat surface or by shining a light between
the push rod and the flat surface.
A wear pattern along the length of the push rod is
not normal. Inspect the engine cylinder head for ob-
struction if this condition exists.
INSTALLATION
(1) Lubricate the ball ends of the push rods with
Mopar Engine Oil Supplement, or equivalent and in-
stall push rods in their original locations. Ensure
that the bottom end of each push rod is centered in
the tappet plunger cap seat.
(2) Using Mopar Engine Oil Supplement, or equiv-
alent, lubricate the area of the rocker arm that the
pivot contacts. Install rocker arms, pivots and bridge
above each cylinder in their original position.
(3) Loosely install the capscrews through each
bridge.
(4) At each bridge, tighten the capscrews alter-
nately, one turn at a time, to avoid damaging the
bridge. Tighten the capscrews to 28 Nzm (21 ft. lbs.)
torque.
(5) Install the engine cylinder head cover.
VALVE SPRINGS AND OIL SEALS
This procedure can be done with the engine cylin-
der head installed on the block.
REMOVAL
Each valve spring is held in place by a retainer and
a set of conical valve locks. The locks can be removed
only by compressing the valve spring.
(1) Remove the engine cylinder head cover.
(2) Remove capscrews, bridge and pivot assemblies
and rocker arms for access to each valve spring to be
removed.
(3) Remove push rods. Retain the push rods,
bridges, pivots and rocker arms in the same order
and position as removed.
(4) Inspect the springs and retainer for cracks and
possible signs of weakening.
(5) Remove the spark plug(s) adjacent to the cylin-
der(s) below the valve springs to be removed.
(6) Install a 14 mm (1/2 inch) (thread size) air hose
adaptor in the spark plug hole.
(7) Connect an air hose to the adapter and apply
air pressure slowly. Maintain at least 621 kPa (90
psi) of air pressure in the cylinder to hold the valves
against their seats. For vehicles equipped with an air
conditioner, use a flexible air adaptor when servicing
the No.1 cylinder.
(8) Tap the retainer or tip with a rawhide hammer
to loosen the lock from the retainer. Use Valve Spring
Fig. 2 Rocker Arm Assembly
J2.5L ENGINE 9 - 23