EXHAUST NOISE BETWEEN EXHAUST SEAL & FRONT EXHAUST

SUBJECT: EXHAUST NOISE BETWEEN EXHAUST SEAL AND FRONT EXHAUST PIPE (REPLACE EXHAUST SEAL AND FRONT EXHAUST PIPE)

MODELS: 1992-93 BUICK SKYLARK 1992-93 OLDSMOBILE ACHIEVA 1992-93 PONTIAC GRAND AM WITH 3300 ENGINE (VIN N - RPO LG7)

CONDITION:

SOME OWNERS MAY COMMENT ABOUT AN ENGINE EXHAUST NOISE THAT IS TRACEABLE TO THE VICINITY OF THE EXHAUST SEAL AND FRONT EXHAUST PIPE CONNECTION.

CAUSE:

THE FRONT EXHAUST PIPE FLANGE SURFACE THAT MATES TO THE EXHAUST SEAL MAY BE WORN THROUGH AND SPLIT, CAUSING AN EXHAUST NOISE.

CORRECTION:

REPLACE THE CURRENT EXHAUST SEAL AND FRONT EXHAUST PIPE WITH A SERVICE SEAL AND PIPE. THE SERVICE SEAL IS MADE FROM DIFFERENT MATERIAL WHICH IS NOT AS ABRASIVE AS THE PRODUCTION SEAL. THE SERVICE FRONT EXHAUST PIPE IS A REPLACEMENT UNIT WITHOUT AN OXIDATION CATALYTIC CONVERTER ATTACHED TO IT.

SERVICE INFORMATION TO DIAGNOSE THE CONDITION, THE TECHNICIAN SHOULD START THE VEHICLE AND LISTEN FOR EXHAUST NOISE NEAR THE EXHAUST SEAL.

IF A NOISE IS DETECTED IN THIS AREA, FOLLOW THE PROCEDURE OUTLINED BELOW TO INSTALL THE SERVICE FRONT EXHAUST PIPE:

1. REMOVE THE FRONT EXHAUST PIPE FROM THE VEHICLE PER SERVICE MANUAL INSTRUCTIONS.

2. SEPARATE THE OXIDATION CATALYTIC CONVERTER FROM THE PRODUCTION FRONT EXHAUST PIPE BY CUTTING THE PIPE WITH APPROPRIATE TUBING CUTTERS AS CLOSE TO THE WELD AS POSSIBLE. REFER TO ILLUSTRATION.

3. REMOVE ALL BURRS FROM THE ID OF THE CATALYTIC CONVERTER INLET PIPE.

4. INSTALL A NEW SERVICE EXHAUST SEAL ONTO THE RIGHT EXHAUST MANIFOLD.

5. ATTACH THE SERVICE FRONT EXHAUST PIPE TO THE EXHAUST MANIFOLD.

6. SLIP THE CLAMP OVER THE OXIDATION CATALYTIC CONVERTER INLET PIPE.

7. SLIP THE OXIDATION CATALYTIC CONVERTER ONTO THE FRONT EXHAUST PIPE.

8. INSTALL A NEW OXIDATION CATALYTIC CONVERTER TO INTERMEDIATE PIPE GASKET, IF NEEDED, AND FASTEN THE INTERMEDIATE PIPE TO THE REAR OF THE OXIDATION CATALYTIC CONVERTER.

9. TIGHTEN THE EXHAUST CLAMP.

10. START THE VEHICLE AND INSURE NO EXHAUST LEAKS ARE PRESENT.

************** INSERT ILLUSTRATION HERE ********************

PARTS INFORMATION

SERVICE EXHAUST SEAL 24504544 SERVICE FRONT EXHAUST PIPE 12537203 EXHAUST CLAMP ASSEMBLY 10062891 OXIDATION CATALYTIC CONVERTER TO INTERMEDIATE PIPE GASKET 22545048

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION

LABOR OPERATION DESCRIPTION LABOR TIME L2160 R+R FRONT EXHAUST PIPE AND SEAL 0.5 HRS

FIGURES: 1

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.