Riviera V6-3.8L SC VIN 1 (1995)
Oil Pan: All Technical Service Bulletins
Engine - Leak at Oil Pan Sealing Flange
File In Section: 6 - Engine
Bulletin No.: 77-61-22
Date: October, 1997
Subject:
Engine Oil Leak at Oil Pan Sealing Flange
(Replace Oil Pan and Oil Pan Gasket)
Models:
1995-97 Buick Park Avenue, LeSabre, Regal, Riviera
1995 Chevrolet Lumina APV
1995-97 Oldsmobile Ninety Eight, Eighty Eight, LSS
1995 Oldsmobile Silhouette
1997 Oldsmobile Regency
1995-97 Pontiac Bonneville
1996-97 Pontiac Grand Prix
1995 Pontiac Trans Sport
with 3800 Engine (VINs 1, K, L - RPOs L67, L36, L27)
Condition
Some owners may comment about an engine oil leak that appears to originate from the bottom of the engine.
Cause
The engine oil pan sealing flange may have a wavy surface preventing the oil pan gasket to properly seal.
Diagnostics
1.
Install oil dye (P/N 12345795) into the crankcase and warm the engine up to operating temperature by driving the vehicle a few miles.
2.
Raise the vehicle on a hoist with the engine running and thoroughly inspect for oil leaks by using a black light. Pay particular attention to the oil
pan sealing flange.
Important:
AN OIL LEAK ORIGINATING ABOVE THE OIL PAN SEALING SURFACE MAY BE DUE TO A CRANKSHAFT REAR OIL SEAL
HOUSING GASKET LEAK, AN INTAKE END SEAL LEAK, MAIN BEARING SIDE BOLT LEAK, OR OTHER SOURCES. REPAIR ANY
LEAKS ORIGINATING ABOVE THE OIL PAN FIRST BEFORE REPLACING THE OIL PAN.
3.
Shut the engine off and remove the flywheel inspection cover.
4.
Use the black light to check for oil leaks in the flywheel area. A leak in this area may be due to a split gasket on the crankshaft rear oil seal
housing.
Correction
1.
If the leak appears to originate at the oil pan flange, then replace the oil pan and oil pan gasket using procedures outlined in the appropriate service
repair manual. The engine oil pan part numbers listed in this bulletin supersede previous part numbers and have much improved sealing flange
flatness.
Important:
1.
DO NOT USE ANY TYPE OF ADHESIVE ON THE OIL PAN GASKET.
2.
THOROUGHLY CLEAN ALL THE OIL PAN BOLTS AND APPLY TWO DROPS OF GM P/N 12345382 (LOCTITE 242 - BLUE)
THREAD LOCKER TO THE THREADED END OF THE BOLTS BEFORE INSTALLATION.
3.
TORQUE OIL PAN BOLTS TO 14 N.m (125 lb in.).
2.
If the leak appears to originate in the flywheel area, then remove the crankshaft rear oil seal housing and install a new gasket and a new crankshaft
rear oil seal per Bulletin 77-61-16.
