For 1990-2009 cars

# INFO. ON CRANKSHAFT IDENTIFICATION

#### SUBJECT: INFORMATION ON CRANKSHAFT IDENTIFICATION

#### MODELS: 1988-94 BUICK SKYLARK 1990-94 CHEVROLET BERETTA 1987-91 OLDSMOBILE CALAIS 1992-94 OLDSMOBILE ACHIEVA 1990-91 OLDSMOBILE CUTLASS SUPREME 1988-94 PONTIAC GRAND AM 1990-91 PONTIAC GRAND PRIX WITH 2.3L (VINS A, D, 3 - RPOS LG0, LD2, L40)

THIS BULLETIN CANCELS AND SUPERSEDES BULLETIN 976104. PREVIOUS DIVISIONAL PUBLICATIONS WERE: BUICK 89-6-9 PONTIAC 89-6-40 CANADA 89-623-105 OLDSMOBILE SERVICE GUILD - VOLUME 39, NO. 9

#### SERVICE INFORMATION:

CRANKSHAFTS USED IN 1987 - 88 2.3L QUAD-4 ENGINES ARE DIFFERENT FROM THE CRANKSHAFTS USED IN 1989 - 1994 2.3L QUAD-4 ENGINES. THESE CRANKSHAFTS ARE NOT INTERCHANGEABLE.

THE 1987 AND 1988 CRANKSHAFTS HAVE A RELUCTOR WHEEL WITH 0 DEGREES OF ADVANCE. THE 1989 THROUGH 1994 CRANKSHAFTS HAVE A RELUCTOR WHEEL WITH 15 DEGREES OF ADVANCE.

A 15 DEGREE ADVANCE CRANKSHAFT INSTALLED IN A VEHICLE REQUIRING A 0 DEGREE CRANKSHAFT WILL EXHIBIT AN IDLE FLUCTUATION OR SURGE CONDITION. A 0 DEGREE CRANKSHAFT INSTALLED IN A VEHICLE REQUIRING A 15 DEGREE ADVANCE CRANKSHAFT WILL EXHIBIT A LACK OF POWER. IF THE CRANKSHAFT WAS EVER REPLACED WITH THE INCORRECT ONE, THE ABOVE INFORMATION COULD ASSIST IN DIAGNOSING THE VEHICLE.

THE 1987 AND 1988 CRANKSHAFTS CAN BE IDENTIFIED BY A BLUE PAINT DOT ON THE #8 CRANKSHAFT COUNTERWEIGHT. THE 1989 THROUGH 1994 CRANKSHAFTS CAN BE IDENTIFIED BY A WHITE PAINT DOT ON THE #8 CRANKSHAFT COUNTERWEIGHT. IF THE PAINT DOTS ARE NOT DETECTABLE, REFER TO FIGURES 1 + 2 TO ASSIST IN IDENTIFYING THE QUESTIONABLE CRANKSHAFT.

FIGURES: 2 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 OCCURRING 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 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 1994. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.