CONDITION POSSIBLE CAUSES CORRECTION
OIL LEAKS 1. Gaskets and O-Rings. Misaligned
or damaged.1. Replace as necessary.
(a) Loose fasteners, broken or
porous metal parts.(a) 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.
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.
CONDITION POSSIBLE CAUSES CORRECTION
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 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. Clean the spark plug recesses with compressed air.
2. Remove the spark plugs.
3. Disable the fuel system (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY - DESCRIPTION).
4. Remove the ASD relay (Refer to 8 - ELECTRICAL/IGNITION CONTROL/AUTO SHUTDOWNRELAY-
REMOVAL).
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 cylinders.
7. (Refer to 9 - ENGINE - SPECIFICATIONS) for the correct engine compression pressures.
DIAGNOSIS AND TESTING - CYLINDERCOMBUSTION PRESSURE LEAKAGE
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.
1. Check the coolant level and fill as required. DO NOT install the radiatorcap.
2. Start and operate the engine until it attains normal operating temperature, then turn the engine OFF.
3. Remove the spark plugs.
4. Remove the oil filler cap.
5. Remove the air cleaner hose.
6. 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 and 552 kPa (80 psi) recommended.
7. Perform the test procedures on each cylinder according to the tester manufacturer’s instructions. Set piston of
cylinder to be tested at TDC compression,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 pressure, a minimum of 414 kPa (60 psi) should be maintained in the
cylinder.
Refer to CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART .
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary.
Inspect valve springs. Replace as
necessary.
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary.
Inspect valve springs. Replace as
necessary.
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuckorbrokenpistonrings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
STANDARD PROCEDURE
STANDARD PROCEDURE - REPAIR DAMAGED OR WORN THREADS
CAUTION: Be sure that the tapped holes maintain the original center line.
Damaged or worn threads can be repaired. Essentially, this repair consistsof:
Drilling out worn or damaged threads.
Tapping the hole with a special Heli-Coil Tap, or equivalent.
Installing an insert into the tapped hole to bring the hole back to its original thread size.
STANDARD PROCEDURE - 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
MoparGasket 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
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
material also will prevent corrosion. Mopar
Gasket Sealant is available in a 13 oz. aerosol can or 4oz./16 oz. can
w/applicator.
FORM-IN-PLACE GASKET AND SEALER APPLICATION
Assembling parts using a form-in-place gasket requires care but it’s easier than using precut gaskets.
Mopar
Gasket 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, a 3.17 or 6.35 mm (1/8 or 1/4 in.)
drop is placed in the center of the gasket contact area. Uncured sealant maybe removed with a shop towel. Com-
ponents should be torqued in place while the sealant is still wet to the touch (within 10 minutes). 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.
STANDARD PROCEDURE - 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 (3).
Abrasive pad (1) or paper to clean cylinder block
and head.
High speed power tool (1) with an abrasive pad
orawirebrush.
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.
Drill motor with 3M Roloc™ Bristle Disc (white or yellow).
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.
17. Disconnect the engine wiring harness at the fol-
lowing points :
Intake air temperature (IAT) sensor (4)
Fuel Injectors
Throttle Position (TPS) Switch (2)
Idle Air Control (IAC) Motor (3)
Engine Oil Pressure Switch
Engine Coolant Temperature (ECT) Sensor
Manifold Absolute Pressure MAP) Sensor
Camshaft Position (CMP) Sensor
Coil Over Plugs
Crankshaft Position Sensor
18. Remove coil over plugs.
19. Release fuel rail pressure.
20. Remove fuel rail and secure away from engine.
NOTE: It is not necessary to release the quick
connect fitting from the fuel supply line for engine
removal.
21. Remove the PCV hose.
22. Remove the breather hoses.
23. Remove the vacuum hose for the power brake
booster.
24. Disconnect knock sensors.
25. Remove engine oil dipstick tube.
26. Remove intake manifold.
27. Install engine lifting fixture,special tool#8247, using original fasteners from the removed intake manifold, and
fuel rail. Torque to factory specifications.
NOTE: Recheck bolt torque for engine lift plate before removing engine.
28. Secure the left and right engine wiring harnesses away from engine.
29. Raise vehicle.
30. Disconnect oxygen sensor wiring.
8. Install the starter (4).
9. Connect the crankshaft position sensor.
10. Install the engine block heater power cable, if
equipped.
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
11. Install the structural cover.
NOTE: New clamps must be used on exhaust man-
ifold flanges. Failure to use new clamps may
result in exhaust leaks.
12. Install the left and right exhaust pipes.
13. Connect the left and right oxygen sensors.
14. Lower vehicle.
15. Remove the engine lift plate.
16. Connect the knock sensors.
17. Connect the engine to body ground straps at the
left side of the cowl.
18. Install the intake manifold.
19. Install the engine oil dipstick tube.
20. Install the power brake booster vacuum hose.
21. Install the breather hoses.
22. Install the PCV hose.
23. Install the fuel rail.
24. Install the coil over plugs.
25. Connect the engine wiring harness at the follow-
ing points :
Intake air temperature (IAT) sensor (4)
Fuel Injectors
Throttle Position (TPS) Switch (2)
Idle Air Control (IAC) Motor (3)
Engine Oil Pressure Switch
Engine Coolant Temperature (ECT) Sensor
Manifold Absolute Pressure MAP) Sensor
Camshaft Position (CMP) Sensor
Coil Over Plugs
Crankshaft Position Sensor
26. Reinstall the radiator/cooling module assembly.
27. Connect lower radiator hose.
28. Connect upper radiator hose.
29. Connect throttle and speed control cables.
30. Install the heater hose assembly.
31. Install coolant recovery bottle.
32. Install the power steering pump.
33. Install the generator (3).
34. Install the A/C compressor (2).
35. Install the drive belt.
36. Install the fan shroud with the viscous fan assem-
bly.
37. Install the radiator core support bracket.
38. Install the air cleaner assembly.
39. Refill the engine cooling system.
40. Recharge the air conditioning.
41. Check and fill engine oil.
42. Connect the battery negative cable.
43. Start the engine and check for leaks.
SPECIFICATIONS
SPECIFICATIONS - 3.7L ENGINE
GENERAL SPECIFICATIONS
DESCRIPTION SPECIFICATION
Type 90°SOHCV612Valve
Number of Cylinders 6
Firing Order 1-6-5-4-3-2
Lead Cylinder No. 1 Left Bank
Compression Ratio 9.6:1
Max. Variation Between Cylinders 25%
Metric Standard
Displacement 3.7 Liters 226 Cubic Inches
Bore 93.0 mm 3.66 in.
Stroke 90.8 mm 3.40 in.
Horsepower 211 @ 5200 RPM
Torque 236ft. lbs.@4000 PRM
Compression Pressure 1172-1551 kPa 170-225 psi
CYLINDER BLOCK
DESCRIPTION SPECIFICATION
Metric Standard
Bore Diameter 93.013 ± .0075 mm 3.6619 ± 0.0003 in.
Out of Round (MAX) 0.076 mm 0.003 in.
Taper (MAX) 0.051 mm 0.002 in.
PISTONS