COLD ENGINE PISTON KNOCK ON 2.OL (NEW PISTON)

VEHICLES AFFECTED: 1987-89 J AND L CARS

Some customers may comment of a cold engine knock at initial vehicle start-up. This condition may be repaired by installation of tighter fitting pistons available through service parts:

P/N 10112367 0.04mm O.S. P/N 10112368 0.50mm O.S. P/N 10112369 1.00mm O.S.

Piston fit should be reduced to .0008" - .0015 clearance. The cylinder case may need to be honed to achieve the desired piston fit. Refer to the Service Manual Section 6A-20 for proper piston fit instructions.

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.