SMU - SECTION 6A - ENGINE MECHANICAL. Chevrolet Corsica 1990

SUBJECT: SERVICE MANUAL UPDATE-SECTION 6A-ENGINE MECHANICAL- CYLINDER HEAD FLATNESS SPECIFICATION FOR 2.0L AND 2.2L ENGINES (VINS 1, G, 4 - RPOS LL8, LM3, LN2)

MODELS: 1987-89 BUICK SKYHAWK 1993-96 BUICK CENTURY 1987 CADILLAC CIMARRON 1987-96 CHEVROLET BERETTA, CORSICA, CAVALIER 1987-88 OLDSMOBILE FIRENZA 1993-96 OLDSMOBILE CUTLASS CIERA 1987-93 PONTIAC TEMPEST (GM OF CANADA ONLY) 1995-96 PONTIAC SUNFIRE

1994-96 CHEVROLET AND GMC TRUCK S MODELS WITH 2.0L OR 2.2L ENGINES (VINS 1, G, 4-RPOS LL8, LM3, LN2)

THE CYLINDER HEAD FLATNESS SPECIFICATION WAS OMITTED IN SOME OF THE SERVICE MANUALS FOR THE ABOVE VEHICLES.

CYLINDER HEAD FLATNESS SPECIFICATION:

THE CYLINDER HEAD CAN BE REUSED IF THE CYLINDER HEAD WARPAGE IS LESS THAN 0.05 MM (0.002 IN.) WITHIN ANY 152 MM (6.0 IN.) AREA OF THE CYLINDER HEAD SEALING SURFACE OR 0.1 MM (0.004 IN.) OVER THE ENTIRE LENGTH OF THE CYLINDER HEAD.

RESURFACE THE CYLINDER HEAD IF WARPAGE IS OVER 0.05 MM (0.002 IN.) WITHIN ANY 152 MM (6.0 IN.) AREA, OR MORE THAN 0.1 MM (0.004 IN.) AND LESS THAN 0.25 MM (0.010 IN.) OVER THE ENTIRE LENGTH OF THE CYLINDER HEAD. THE CYLINDER HEAD MUST BE REPLACED IF WARPAGE IS OVER 0.25 MM (0.010 IN.).

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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.