INCREASED OIL CONSUMPTION (REPLACE LOWER INTAKE GASKET). Buick Skylark 1994

SUBJECT: INCREASED OIL CONSUMPTION (REPLACE LOWER INTAKE GASKET)

MODELS: 1994-96 BUICK CENTURY, REGAL, SKYLARK 1994-96 CHEVROLET LUMINA, MONTE CARLO 1994-96 OLDSMOBILE ACHIEVA, CUTLASS CIERA, CUTLASS SUPREME 1994-96 PONTIAC GRAND AM, GRAND PRIX WITH 3100 V6 ENGINE (VIN M - RPO L82)

CONDITION:

SOME OWNERS MAY COMMENT ON A SUDDEN INCREASE IN ENGINE OIL USAGE AS THE VEHICLE MILEAGE APPROACHES 30,000 MILES. THE INCREASE IN ENGINE OIL USAGE IS DRAMATIC, TYPICALLY IN THE 600-800 MILES PER 1 QUART RANGE (965-1287 KILOMETERS PER .946 LITERS). NORMAL OIL ECONOMY RANGES IN THE LESS THAN 1 QUART IN 2000 MILES (.946 LITERS IN 3218 KILOMETERS).

CAUSE:

AFTER PROLONGED EXPOSURE TO FUEL ENRICHED AIR AND THERMAL CYCLING OF THE ENGINE, THE LOWER INTAKE MANIFOLD GASKETS TAKE A COMPRESSION SET. ENGINE OIL IS THEN DRAWN INTO THE LOWER INTAKE MANIFOLD AND INGESTED ALONG WITH THE AIR FUEL MIXTURE. DUE TO THE INTERNAL THERMAL TEMPERATURES AND THE EFFICIENCY OF THE CATALYTIC CONVERTER, NO ENGINE OIL SMOKE IS VISIBLE FROM THE VEHICLES EXHAUST TAILPIPE.

CORRECTION:

REFERENCE CORPORATE SERVICE BULLETIN 766004 AND FOLLOW THE GUIDELINES SET FORTH IN IT. CHECK FOR ANY EXTERNAL OIL LEAKS AND THEN COMPLETE AN OIL CONSUMPTION TEST. IF IT IS DETERMINED THAT THE VEHICLE IS USING OIL AT A RATE GREATER THAN 1 QUART (.946L) IN 2000 MILES (3218 KM), REPLACE THE LOWER INTAKE MANIFOLD GASKETS.

PARTS INFORMATION:

PART NUMBER DESCRIPTION QUANTITY ----------- ----------- --------

12537009 1994 1995 1ST DESIGN LOWER INTAKE MANIFOLD GASKET KIT 1

12480829 1995 SECOND DESIGN 1996 LOWER INTAKE MANIFOLD GASKET KIT 1

NOTE: 1ST DESIGN BALL AND NUT TYPE ROCKER ARM. 2ND DESIGN ROLLER ROCKER ARM.

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIR UNDER WARRANTY, USE:

LABOR OPERATION LABOR OPERATION NUMBER DESCRIPTION TIME --------------- ----------- ---------------

J0200 MANIFOLD AND/OR GASKET, USE PUBLISHED LABOR INTAKE - REPLACE OPERATION TIME

FIGURES: 00 ATTACHMENTS: 00

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.