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CONDITION POSSIBLE CAUSES CORRECTION
ENGINE STALLS OR
ROUGH IDLE1. Carbon buildup on throttle plate. 1. Remove throttle body and de-carbon.
2. Engine idle speed too low. 2. Check Idle Air Control circuit. Refer to
the appropriate Diagnostic Information for
IAC motor testing.
3. Worn or incorrectly gapped spark
plugs.3. Replace spark plugs or set gap.
4. Faulty or crossed ignition cables. 4. Check for correct firing order or replace
ignition cables as necessary.
5. Faulty coil(s). 5. Test and replace as necessary.
6. Intake manifold vacuum leak. 6. Inspect intake manifold gasket and
vacuum hoses. Replace as necessary.
ENGINE MISSES ON
ACCELERATION1. Worn or incorrectly gapped spark
plugs.1. Replace spark plugs or set gap.
2. Faulty ignition cables. 2. Replace ignition cables as necessary.
3. Dirt or water in fuel system. 3. Clean system and replace fuel filter.
4. Burned, warped, or pitted valves. 4. Install new or reface valves as
necessary.
5. Faulty coil(s). 5. Test and replace as necessary.
ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES 1. High or low oil level incrankcase. 1. Check for correct oil level. Adjust oil level
by draining or adding as needed.
2. Thin or diluted oil. 2. Change oil and filter.
3. Low oil pressure. 3. Check engine oil level. If OK, perform oil
pressure test. (Refer to 9 - ENGINE/
LUBRICATION - DIAGNOSIS AND
TESTING).
4. Dirt in tappets/lash adjusters. 4. Clean/replace hydraulic tappets/lash
adjusters.
5. Bent push rod(s). 5. Replace push rod(s) as necessary.
6. Worn rocker arms. 6. Replace worn rocker arms and inspect
oil supply to rocker arms.
7. Worn tappets/lash adjusters. 7. Replace hydraulic tappets/hydrauliclash
adjusters.
8. Worn valve guides. 8. Ream and install new valves with
oversize stems.
9. Excessive runout of valve seats
on valve faces.9. Grind valve seats and valves.
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CONDITION POSSIBLE CAUSES CORRECTION
CONNECTING ROD
NOISE1. Insufficient oil supply. 1. Check engine oil level.
2. Low oil pressure. 2. Check engine oil level. If OK, perform oil
pressure test. Inspect oil pump relief valve
and spring. (Refer to 9 - ENGINE/
LUBRICATION - DIAGNOSIS AND
TESTING).
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Measure bearings for correct clearance.
Repair as necessary.
5. Connecting rod journal out-of-
round.5. Replace crankshaft or grind journals.
6. Misaligned connecting rods. 6. Replace bent connecting rods.
MAIN BEARING NOISE 1. Insufficient oil supply. 1. Check engine oil level.
2. Low oil pressure. 2. Check engine oil level. If OK, perform oil
pressure test. Inspect oil pump relief valve
and spring. (Refer to 9 - ENGINE/
LUBRICATION - DIAGNOSIS AND
TESTING).
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Measure bearings for correct clearance.
Repair as necessary.
5. Excessive end play. 5. Check No. 3 bearing for wear on flanges.
6. Crankshaft journal out-of-round
and/or worn.6. Grind journals or replace crankshaft.
7. Loose flywheel. 7. Inspect crankshaft, flywheel, and bolts for
damage. Tighten bolts to correct torque.
OIL PRESSURE DROP 1. Low oil level. 1. Check oil level and fill if necessary.
2. Faulty oil pressure sending unit. 2. Replace sending unit.
3. Clogged oil filter. 3. Install new oil filter.
4. Worn oil pump. 4. Replace worn gears or oil pump
assembly.
5. Thin or diluted oil. 5. Change oil to correct viscosity.
6. Excessive bearing clearance. 6. Measure bearings for correct clearance.
7. Oil pump relief valve stuck. 7. Remove relief valve. Inspect valve and
spring. Replace as necessary.
8. Oil pump pick up tube restricted,
cracked, or damaged.8. Remove oil pan and inspect oil pump
pick up tube. Clean or replace as
necessary.
9. Oil pump cover loose, warped, or
cracked.9. Inspect/tighten cover screws or install
new oil pump, if necessary.
OIL LEAKS 1. Misaligned or deteriorated
gaskets.1. Replace gaskets.
2. Loose fastener, broken or porous
component.2. Tighten, repair or replace component.
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CONDITION POSSIBLE CAUSES CORRECTION
EXCESSIVE OIL
CONSUMPTION OR
SPARK PLUGS OIL
FOULED1. PCV system malfunction. 1. Check and repair PCV system as
necessary.
2. Defective valve stem seal(s). 2. Repair or replace seal(s).
3. Worn or broken piston rings. 3. Hone cylinder bores. Install new rings.
4. Scuffed pistons/cylinder walls. 4. Hone cylinder bores and replace pistons
as necessary.
5. Carbon in oil control ring groove. 5. Remove rings and de-carbon piston.
6. Worn valve guides. 6. Ream and install new valves with
oversize stems.
7. Piston rings fitted too tightly in
grooves.7. Remove piston rings. Check ring end
gap and side clearance. Replace as
necessary.
CYLINDER COMPRESSION PRESSURE TEST
The results of a cylinder compressionpressure test can be utilized to diagnose several engine malfunctions.
Ensurethebatteryiscompletelychargedandtheenginestartermotorisingood operating condition. Otherwise the
indicated compression pressures may not be valid for diagnosis purposes.
1. Check engine oil level and add oil if necessary.
2. Drive the vehicle until engine reaches normal operating temperature. Select a route free from traffic and other
forms of congestion, observe all traffic laws, and accelerate through thegears several times briskly.
3. Remove the Auto Shut Down (ASD) relay from the Power Distribution Center(PDC).
4. Disconnect ignition cables from spark plugs.
5. Remove all spark plugs from engine. As spark plugs are being removed, check electrodes for abnormal firing
indicators fouled, hot, oily, etc. Record cylinder number of spark plug for future reference.
6. Be sure throttle blade is fully open during the compression check.
7. Insert compression gauge adaptor Special Tool 8116 or the equivalent, into the No. 1 spark plug hole in cylinder
head. Connect the 0-500 psi (Blue) pressure transducer (Special Tool CH7059) with cable adaptors to the scan
tool. For Special Tool identification, (Refer to 9 - ENGINE - SPECIAL TOOLS).
8. Crank engine until maximum pressure is reached on gauge. Record this pressure as No. 1 cylinder pressure.
9. Repeat the previous step for all remaining cylinders.
10. Compression should not be less than 689 kPa (100 psi) and not vary more than 25 percent from cylinder to
cylinder.
11. If one or more cylinders have abnormally low compression pressures, repeat the compression test.
12. If the same cylinder or cylinders repeat an abnormally low reading on the second compression test, it could
indicate the existence of a problem in the cylinder in question.The recommended compression pressures
are to be used only as a guide to diagnosing engine problems. An engine should not be disassembled
to determine the cause of low compression unless some malfunction is present.
CYLINDER COMBUSTIONPRESSURE LEAKAGE TEST
The combustion pressure leakage test provides an accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
Exhaust and intake valve leaks (improper seating).
Leaks between adjacent cylinders or into water jacket.
Any causes for combustion/compression pressure loss.
WARNING: Do not remove the cooling system pressure cap with the system hot and under pressure
because serious burns from coolant can occur.
1. Check the coolant level and fill as required. DO NOT install the pressurecap.
2. Start and operate the engine until it attains normal operating temperature, then turn the engine OFF.
Page 2028 of 5267

3. Clean spark plug recesses with compressed air.
4. Remove the spark plugs.
5. Remove the oil fill cap.
6. Remove the air cleaner.
7. Calibrate the tester according to the manufacturer’s instructions. The shop air source for testing should maintain
483 kPa (70 psi) minimum, 1,379 kPa (200 psi) maximum, with 552 kPa (80 psi) recommended.
8. Perform the test procedures on each cylinder according 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 coolant pressure bottle.
All gauge pressure indications should be equal, with no more than 25 percent leakage per cylinder.
FOR EXAMPLE:At 552 kPa (80 psi) input pressure, a minimum of 414 kPa (60 psi) should be maintained in the
cylinder.
CYLINDER HEAD GASKET FAILURE DIAGNOSIS
A cylinder head gasket leak can be located between adjacent cylinders, between a cylinder and the adjacent water
jacket, or an external coolant leak may be present.
Possible indications of the cylinder head gasket leaking between adjacent cylinders are:
Loss of engine power
Engine misfiring
Poor fuel economy
Possible indications of the cylinder head gasket leaking between a cylinder and an adjacent water jacket are:
Engine overheating
Loss of coolant
Excessive steam (white smoke) emitting from exhaust
Coolant foaming
CYLINDER-TO-CYLINDER LEAKAGE TEST
To determine if an engine cylinder head gasket is leaking between adjacentcylinders, follow the procedures in Cyl-
inder Compression Pressure Test in this section. An engine cylinder head gasket leaking between adjacent cylinders
will result in approximately a 50-70% reduction in compression pressure.Cylinders adjacent to each other will both
have low compression.
CYLINDER-TO-WATER JACKET LEAKAGE TEST
WARNING: Use extreme caution when the engine is operating with coolant pressure cap removed.
VISUAL TEST METHOD
With the engine cool, remove the coolant pressure cap. Start the engine andallow 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.Excessive pressure built up, by
continuous engine operation, must be released to a safe pressure point. Never permit pressure 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.
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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.
HYDRAULIC TAPPET NOISE DIAGNOSIS
PRELIMINARY STEP TO CHECKING THE HYDRAULIC TAPPETS
Before disassembling any part of the engine to correct tappet noise, checkengine oil level and oil pressure.
1. Check the engine oil level.
Oil Level Check: stop engine after reaching normal operating temperature
The oil level should never be above the FULL mark on dipstick, or below the ADD mark. Either of
these two conditions could be responsible for noisy tappets. Allow 5 minutes to stabilize oil level,
check dipstick.
2. Remove oil pressure sensor.
3. Install a reliable oil pressure gauge at oil pressure sensor location.
The oil pressure should be 206.8 - 551.6 kPa (30 - 80 psi) at 2000 rpm.
OIL LEVEL TOO HIGH
If oil level is above the FULL mark on dipstick, it is possible for the connecting rods to dip into the oil while engine
is running and create foam. Foam in oil pan would be fed to the hydraulic tappets by the oil pump causing them to
become soft and allow valves to seat noisily.
OIL LEVEL TOO LOW
Low oil level may allow pump to take in air which when fed to the tappets, causes them to become soft and allows
valves to seat noisily. Any leaks on intake side of pump through which air canbedrawnwillcreatethesametappet
action. Check the lubrication system from the intake strainer to the pump cover, including the relief valve retainer
cap. When tappet noise is due to aeration, it may be intermittent or constant, and usually more than one tappet will
be noisy. When oil level and leaks have been corrected, engine should be operated at fast idle to allow all of the air
inside of the tappets to be bled out.
VALVE TRAIN NOISE DIAGNOSIS
To determine source of valve train noise, operate engine at idle with cylinder head covers removed and listen for
source of the noise.
NOTE: Worn valve guides or cocked springs are sometimes mistaken for noisytappets. If such is the case,
noise may be dampened by applying side thrust on the valve spring. If noise is not appreciably reduced, it
can be assumed the noise is in the tappet. Inspect the rocker arm push rod sockets and push rod ends for
wear.
Valve tappet noise ranges from light noise to a heavy click. A light noise isusually caused by excessive leak-down
around the unit plunger which will necessitate replacing the tappet, or bythe plunger partially sticking in the tappet
body cylinder. A heavy click is caused either by a tappet check valve not seating, or by foreign particles becoming
wedged between the plunger and the tappet body causing the plunger to stickin the down position. This heavy click
will be accompanied by excessive clearance between the valve stem and rocker arm as valve closes. In either case,
tappet assembly should be removed and replaced.
ENGINE OIL LEAK INSPECTION
Begin with a thorough visual inspection of the engine, particularly at thearea of the suspected leak. If an oil leak
source is not readily identifiable, thefollowingstepsshouldbefollowed:
1. Do not clean or degrease the engine at this time because some solvents maycause 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.
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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 as necessary.
4. If dye is not observed, drive the vehicle at various speeds for approximately 24 km (15 miles), and repeat inspec-
tion.
5.If the oil leak source is not positively identified at this time, proceed with the air leak detection test method
as follows:
1. Disconnect the PCV hoses at the cylinder head covers and plug or cap the outlet on the covers.
2. 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.
3. Gradually apply air pressure from 6.89 kPa (1 psi) to 17.23 kPa (2.5 psi) maximum while applying soapy water
at the suspected source. Adjust the regulator to the suitable test pressure that provides the best bubbles which
will pinpoint the leak source. If the oil leak is detected and identified, repair per service manual procedures.
4. If the leakage occurs at the crankshaft 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. Remove the air hose, allplugs, and caps. Connect the PCV
hoses. Proceed to next step.
7. Clean the oil off the suspect oil leak area using a suitable solvent. Drive the vehicle at various speeds approx-
imately 24 km (15 miles). Inspect the engine for signs of an oil leak by usinga black light.
NOTE: If oil leakage is observed at the dipstick tube to oil pan location; remove the tube, clean and reseal
using Mopar
Stud & Bearing Mount (press fit tube applications only), and for O-ring style tubes, remove
tube and replace the O-ring seal.
INSPECTION FOR REAR SEAL AREA LEAKS
Since it is sometimes difficult to determine the source of an oil leak in therear seal area of the engine, a more
involved inspection is necessary. The following steps should be followedto 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 clutch housing inspection cover and inspect rear of block for evidence of oil. Use a black light to check
for the oil leak. If a leak is present in this area, remove transmission for further inspection.
a. Circular spray pattern generally indicates seal leakage or crankshaftdamage.
b. Where leakage tends to run straight down, possible causes are a porous block, oil gallery cup plug or rear
crankshaft seal retainer gasket leak. See proper repair procedures for these items.
4. If no leaks are detected, pressurize the crankcase as previously described.
CAUTION: Do not exceed 20.6 kPa (3 psi).
5. If the leak is not detected, very slowly turn the crankshaft and watch forleakage. 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 canbe 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 disassembled.
7. After the oil leak root cause and appropriate corrective action have been identified, replace component(s) as
necessary.
Page 2031 of 5267

STANDARD PROCEDURE
ENGINE CORE AND OIL GALLERY PLUGS
Using a blunt tool such as a drift (4) and a hammer,
strike the bottom edge of the cup plug. With the cup
plug rotated, grasp firmly with pliers (2) or other suit-
able tool and remove plug (5).
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 cylinder
block or head. Be sure to remove old sealer. Lightly
coat inside of cup plug hole with Mopar
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.
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 apply-
ing 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-overwhich 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. Mopar
Engine RTV
GEN II, Mopar
ATF-RTV, and MoparGasket Maker gasket materials, each have different properties and can not
be used in place of the other.
MOPAR
ENGINE RTV GEN II
Mopar
Engine RTV GEN II is used to seal components exposed to engine oil. This material is a specially 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.
MOPAR
AT F R T V
Mopar
ATF RTV is a specifically designed black silicone rubber RTV that retains adhesion and sealing properties
to seal components exposed to automatic transmission fluid, engine coolants, and moisture. This material is avail-
able in three ounce tubes and has a shelf life of one year. After one year thismaterial will not properly cure. Always
inspect the package for the expiration date before use.
MOPAR
GASKET MAKER
Mopar
Gasket Maker is an anaerobic type gasket material. The material cures in the absence of air when
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.
MOPAR
BED PLATE SEALANT
Mopar
Bed Plate Sealant is a unique (green-in-color) anaerobic type gasket material that is specially made to seal
the area between the bedplate and cylinder block without disturbing the bearing clearance or alignment of these
components. The material cures slowly in the absence of air when torqued between two metallic surfaces, and will
rapidly cure when heat is applied.
MOPAR
GASKET SEALANT
Mopar
Gasket Sealant is a slow drying, permanently soft sealer. This material isrecommended for sealing
threaded fittings and gaskets against leakage of oil and coolant. Can be used on threaded and machined parts
under all temperatures. This material is used on engines with multi-layersteel (MLS) cylinder head gaskets. This
Page 2032 of 5267

material also will prevent corrosion. MoparGasket Sealant is available in a 13 oz. aerosol can or 4 oz./16 oz. can
w/applicator.
FORM-IN-PLACE GASKET AND SEALER APPLICATION
MoparGasket Maker material should be applied sparingly 1 mm (0.040 in.) diameter or less of sealant to one
gasket surface. Be certain the material surrounds each mounting hole. Excess material can easily be wiped off.
Components should be torqued in place within 15 minutes. The use of a locating dowel is recommended during
assembly to prevent smearing material off the location.
Mopar
Engine 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,a3.17mmor6.35mm(1/8in.
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 wettothetouch(within10minutes).The
usage of a locating dowel is recommended during assembly to prevent smearing material off the location.
Mopar
Gasket 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 shouldbeusedonengineswithmulti-
layer steel gaskets.
ENGINE GASKET SURFACE PREPARATION
To ensure engine gasket sealing, proper surface prep-
aration 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:
Metal scraper
Abrasive pad or paper to clean cylinder block
and head
High speed power tool with an abrasive pad or a
wire brush (1)
NOTE: Multi-Layer Steel (MLS) head gaskets
require a scratch free sealing surface.
Only use the following for cleaning gasket surfaces:
Solvent or a commercially available gasket
remover
Plastic or wood scraper (3)
Drill motor with 3M Roloc™ Bristle Disc (white or yellow) (2)
CAUTION: Excessive pressure or high RPM (beyond the recommended speed), can damage the sealing sur-
faces. The mild (white, 120 grit) bristle disc is recommended. If necessary, the medium (yellow, 80 grit) bris-
tle disc may be used on cast iron surfaces with care.
HYDROSTATIC LOCKED ENGINE
When an engine is suspected to be hydrostatically locked, regardless of what caused the problem, the following
steps should be used.
CAUTION: DO NOT use starter motor to rotate the engine, severe damage may occur.
1. Inspect air cleaner, induction system and intake manifold to ensure system is dry and clear of foreign material.
2. Remove negative battery cable.
3. Place a shop towel around the spark plugs when removing them from the engine. This will catch any fluid that
may possibly be in the cylinder under pressure.
4. With all spark plugs removed, rotate engine crankshaft using a breaker bar and socket.