Engine - Knock at Low Ambient Temperatures

91oldsmobile05

NUMBER: 90-T-208

CORP.REF.NO: 136515R

DATE: November 1991

SECTION: 6A4


SUBJECT: PISTON SCUFFING - 3.1L ENGINE
- REPLACE A PARTIAL ENGINE - NOT THE PISTON


MODELS/YEARS: 1989-90 CUTLASS SUPREME AND 1990 SILHOUETTE
WITH 3.1L ENGINE (VIN D & T)


CONDITION: Some 1989-90 Cutlass Supremes and 1990 Silhouettes 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.