For 1990-2009 cars

# SMU - SECTION 6 - REVISED PISTON RING IDENTIFICATION

REVISION: 09/16/95

THIS BULLETIN IS BEING REVISED TO CHANGE THE MODELS SECTION. **********************************************************************

REVISION: 10/02/95

THIS BULLETIN IS BEING REVISED TO REMOVE PONTIAC GRAND PRIX FROM MODELS SECTION. **********************************************************************

REVISION: 11/03/95

THIS BULLETIN IS BEING REVISED TO ADD APV TO CHEVROLET LUMINA IN MODELS SECTION. PLEASE DISCARD BULLETIN 57-61-29 (SECTION 6 - ENGINE). **********************************************************************

#### SUBJECT: SERVICE MANUAL UPDATE-SECTION 6-REVISED PISTON RING IDENTIFICATION AND INSTALLATION SERVICE PROCEDURES

#### MODELS: 1994-96 BUICK LESABRE, PARK AVENUE, REGAL 1995-96 BUICK RIVIERA 1994-95 CHEVROLET LUMINA APV 1995-96 CHEVROLET CAMARO 1994-95 OLDSMOBILE SILHOUETTE 1994-96 OLDSMOBILE EIGHTY EIGHT, NINETY EIGHT 1994-95 PONTIAC TRANS SPORT 1994-96 PONTIAC BONNEVILLE 1995-96 PONTIAC FIREBIRD WITH 3800 ENGINE (VINS L, K, 1 - RPOS L27, L36, L67)

THIS PROCEDURE REVISES THE PISTON RING INSTALLATION PROCEDURE FOUND IN THE SERVICE MANUAL. USE THE FOLLOWING PROCEDURE WHENEVER SERVICING OF THE PISTON RINGS IS REQUIRED ON THE 3800 ENGINE.

PISTON RING IDENTIFICATION

* PRIOR TO THE 1994 MODEL YEAR THERE WERE TWO MANUFACTURERS MAKING THE TOP PISTON RINGS FOR ALL 3800 APPLICATIONS. THE TOP PISTON RING WAS "MARKED" IN ORDER TO DIFFERENTIATE BETWEEN THE TWO MANUFACTURERS.

* SINCE THE 1994 MODEL YEAR, THERE IS ONLY ONE MANUFACTURER MAKING THE TOP PISTON RING FOR ALL 3800 APPLICATIONS. BECAUSE THERE IS ONLY ONE MANUFACTURER MAKING THE TOP RING IT IS NO LONGER "MARKED".

PISTON RING INSTALLATION

OIL CONTROL RING ASSEMBLY (BOTTOM RING). A. EXPANDER. B. LOWER OIL CONTROL RING. C. UPPER OIL CONTROL RING.

LOWER COMPRESSION RING (SECOND RING). * INSTALL WITH MANUFACTURER'S IDENTIFICATION MARK FACING "UP". * THE SECOND PISTON RING MUST BE INSTALLED WITH MARKS FACING "UP" TO INSURE PROPER OIL CONTROL.

UPPER COMPRESSION RING (TOP RING). * INSTALL WITH MANUFACTURER'S IDENTIFICATION MARK FACING "UP", IF MARKED. * IF THE TOP PISTON RING HAS NO MARK, THEN IT CAN BE INSTALLED IN EITHER DIRECTION.

FIGURES: 0 ATTACHMENTS: 0

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.

COPYRIGHT 1995. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.