B350 1 Ton Van V6-239 3.9L (1990)
Crankshaft Main Bearing Seal: Technical Service Bulletins
Engine Rear Main Bearing Seal - Oil Leak Diagnosis
NO: 09-09-94 Rev. B
GROUP: Engine
DATE: Jan. 20, 1995
SUBJECT:
Oil Leak Diagnosis - Rear Main Bearing Area
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN NUMBER 09-09-94 Rev. A, DATED NOV. 25, 1994 WHICH SHOULD BE
REMOVED FROM YOUR FILES. THE CHANGES HAVE BEEN HIGHLIGHTED WITH **ASTERISKS** AND INVOLVE THE ADDITION OF
A BEARING CLEARANCE CHECK WHICH MUST BE PERFORMED AFTER ANY MODIFICATIONS ARE MADE TO THE MAIN BEARING
CAP.
MODELS:
1989 - 1995
(AB) Ram Van/Wagon
1989 - 1993
(AD) Ram Pickup/Ram Cab & Chassis
1989 - 1995
(AN) Dakota/Dakota Cab & Chassis
1994
(BR)Ram Pickup
1993 - 1995
(ZJ) Grand Cherokee/Grand Wagoneer
NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A 3.9L/5.2L GASOLINE OR 5.2L CNG ENGINE.
DISCUSSION:
Various conditions may cause an engine oil leak. Some conditions may be found easily by the technician, while other conditions are not readily apparent.
This Technical Service Bulletin is a summary of conditions that may generate an engine oil leak complaint in the area of the rear main bearing.
NOTE:
A THOROUGH ENGINE OIL LEAK TEST MUST BE PERFORMED IF THE CONDITION CAUSING THE OIL LEAK IS NOT EASILY
IDENTIFIABLE.
ENGINE OIL LEAK TEST:
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 test procedure may assist in your diagnosis.
DYE TEST
1.
Do not clean or degrease the engine at this time because some solvents may cause rubber to swell and temporarily stop the leak.
2.
Add an oil soluble dye (use as recommended by the 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 florescent dye, particularly at the rear main bearing area. If the oil leak is found and identified,
repair per the Service Manual instructions or per procedures in this TSB.
4.
If dye is not observed, drive the vehicle at various speeds for approximately 1 5 miles (24 km) and repeat step # 2. If an oil leak is not detected,
proceed to the air pressure oil leak test.
AIR PRESSURE TEST
1.
Disconnect the battery.
2.
Raise the vehicle.
3.
Inspect the rear of the block for evidence of oil. Use a black light to check for the oil leak.
NOTE:
TO PERFORM A THOROUGH INSPECTION OF THE REAR MAIN BEARING AREA, REMOVAL OF THE FLYWHEEL MAY BE
REQUIRED.
