PISTON SCUFFING ON 3.1L ENGINE (REPLACE PARTIAL ENGINE ONLY)

Subject: PISTON SCUFFING

Model and Year: 1990 CAVALIER, CORSICA, BERETTA AND LUMINA WITH 3.1L ENGINE 1990 LUMINA (APV) WITH 3.1L ENGINE

Condition: Some 1990 J, L and W cars and U-vans (APV) may exhibit engine piston scuffing, which could result in cold engine knock at low ambient temperatures. This condition will not lead to engine failure and is limited to cylinders #2, #4 and #6.

Cause: Premature wear of the pistons due to low adhesion of the tin plating.

Correction: If pistons need replacement due to scuffing, a partial engine replacement is HIGHLY recommended rather than replacement of individual pistons. This recommendation is made since other pistons in these engines might have to be replaced later.

Labor Operation Number: J 1820

Labor Time: Use applicable time

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.