Engine - #4 Main Bearing Cap Service
90buick11 Bulletin 91-6-1Date Sept. '90
Ref. No. 91-012-6
Corp. Ref. No. 006104
SUBJECT: REMOVAL AND INSTALLATION OF NO. 4 (REAR) MAIN BREARING CAP
MODELS AFFECTED: 1990-91 REGAL WITH 3800 ENGINE (VIN CODE L) 1991 PARK AVENUE, RIVIERA AND REATTA WITH 3800 ENGINE (VIN CODE L) 1991 LESABRE WITH 3800 ENGINE (VIN CODE C) 1991 CENTURY, SKYLARK WITH 3300 ENGINE (VIN CODE N)
Anytime the # 4 (Rear) main bearing cap has been removed during servicing the following installation procedures must be followed.
The # 4 (Rear) main bearing cap must be installed flush with or .254 mm (.010 in.) forward of the rear face of the cylinder block. Misalignment of the cap toward the transaxle may cause interference with the flywheel to converter bolt heads.
The rear main bearing lip seal must be replaced whenever the # 4 (Rear) main bearing cap is removed. The new seal should be installed after the main bearing cap has been installed. Installing the # 4 (Rear) main bearing cap with the rear main bearing lip seal in place may cause pinching or misalignment of the seal resulting in an oil leak.