Engine - Rap Noise During Warm-Up

90buick02

DCS NO. 90-02 GROUP NO. 6 September 28, 1989
SUBJECT: Engine "Rap" Noise During Warm-Up (Noise Goes Away Hot) - 1989/1990 3300 V-6 1990 Early Production 3800 V-6


TO: All Buick Dealers


ATTN: SERVICE MANAGERS BE SURE TO REVIEW THIS INFORMATION WITH YOUR SERVICE DEPARTMENT PERSONNEL


Some owners of 1989-1990 Buick vehicles equipped with 3300 V-6 or 3800 V-6 engines may comment on an engine "rap" or "diesel" type noise prior to the engine reaching nomal operating temperature. The noise will normally appear after one (1) or two (2) minutes of operation and disappear after ten (10) or fifteen (15) minutes of operation. The source of the noise was found to be caused by the addition of a splash oil hole in the pistons. This hole was added to improve high mileage durability and the noise will in no way adversely affect engine operation or durability.

For purposes of customer satisfaction, the noise can be eliminated on 3800 V-6 engines by installing a set of service pistons. GMSPO service pistons do not have the extra splash oil hole drilled.

A service fix for 3300 V-6 engine is currently under investigation.