ENGINE OIL LEAK DIAGNOSIS NEW RTV SEALER FRT/RR MANIFOLD

SUBJECT: ENGINE OIL LEAKS (DIAGNOSIS/APPLY NEW RTV SEALER AT FRONT AND REAR OF MANIFOLD)

VEHICLES AFFECTED: 1990-91 A,J,L AND W CARS W/3.lL ENGINE

Condition:

Oil leaks on the above engines may be misdiagnosed as head gasket failures. However, these leaks may be occurring at the front or rear of the intake manifold where it contacts the cylinder block.

Cause:

Leaks may be due to an insufficient quantity of RTV sealer (where the intake manifold, cylinder block and cylinder head meet) at the front or rear of the intake manifold.

Correction:

Use normal diagnostic measures to determine if the oil leak is at the front or rear of the intake manifold to cylinder case ridge. If a leak is found, use Service Manual repair procedures and clean RTV sealant from front and rear ridges on intake manifold and cylinder case. Apply new RTV sealer, P/N 1052917 (or equivalent) and reassemble intake manifold per Service manual. The sealing bead must run-up the cylinder head face approximately 5mm (3/16 of an inch) at both ends of the front a and rear cylinder block ridges.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.