OIL LEAK AT FILTER ADAPTER NEW OIL FILTER GASKET P/N

VEHICLES AFFECTED: 1989-91 T-TRUCK

CONDITION:

Some 1989-90 and early 1991 T-trucks may exhibit an oil leak at the left rear of the engine coming from the oil filter adapter bolts.

CAUSE:

This condition may be due to the inability of the gasket between the oil filter adapter and engine block to seal properly. This loss of sealing may also result in the adapter bolts losing torque.

CORRECTION:

This condition may be repaired by installing a new oil filter adapter (P/N 10172750) and gasket (P/N 10172754) per the following instructions.

IMPORTANT: Retorquing the bolts with the existing gasket will only result in a temporary fix for the customer.

PROCEDURE:

1. Disconnect negative battery cable and raise vehicle on hoist.

2. Remove transfer case and front axle skid plates from vehicle.

3. Using a long extension through the opening created by removing the front axle skid plate, remove the remote oil filter adapter line bolt.

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.