TIMING CHAIN COVER OIL LEAK R AND R PROCEDURE CHANGE

* This bulletin is being revised to add further applications to this information.

VEHICLES AFFECTED: 1986 Passenger Cars & Trucks (VIN Code N or Z), 5.0L (VIN Code F, G, H or Y), or 5.7L (VIN Code 6, 8, K, L or M) Engines

The 1986 Service Manuals state that the front timing chain cover can'be removed and reinstalled (R and R) without the removal of the oil pan or oil pan gasket. Due to a change in the oil pan gasket, the oil pan and gasket must now be removed in order to "R and R" the front timing chain cover. If the oil pan and gasket are not removed, it can result in an oil leak at the front of the oil pan.

Use the oil pan "R and R" procedures listed in the appropriate section of the 1986 Service Manual when removal of the front timing chain cover becomes necessary.

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.