EXHAUST RATTLE NOISE (SERVICE PROCEDURE). Cadillac Concours 1996

For 1990-2009 cars

# EXHAUST RATTLE NOISE (SERVICE PROCEDURE)

#### SUBJECT: EXHAUST RATTLE NOISE (SERVICE PROCEDURE)

#### MODELS: 1996 CADILLAC CONCOURS, DEVILLE, ELDORADO, SEVILLE, STS WITH 4.6L ENGINE (VINS 9, Y - RPOS L37, LD8)

#### CONDITION:

SOME CUSTOMERS MAY COMMENT ON A METALLIC RATTLE SOUND, WHICH IS PRESENT DURING VEHICLE OPERATION. THIS METALLIC RATTLE IS MOST NOTICEABLE WITH THE A/C CLUTCH ENGAGED DURING IDLE (BRAKE ON OR OFF) AND/OR UNDER LIGHT TO MODERATE ACCELERATION.

#### CAUSE:

THIS NOISE EMANATES FROM THREE TABS WITHIN THE FLEX COUPLING (1) WHERE THREE SECTIONS OF THE EXHAUST MANIFOLD REAR PIPE ARE WELDED TOGETHER.

#### CORRECTION:

TO DETERMINE IF THE EXHAUST MANIFOLD REAR PIPE IS CAUSING THE EXHAUST SYSTEM TO RATTLE, REFER TO THE FOLLOWING PROCEDURE:

1. PLACE THE VEHICLE ON SUITABLE HOIST AND RAISE THE VEHICLE ACCORDING TO THE PROCEDURE OUTLINED IN THE SERVICE MANUAL.

2. START ENGINE AND TURN ON AIR CONDITIONING SYSTEM.

3. WEARING A HEAT PROTECTED GLOVE, GENTLY PUSH THE EXHAUST SYSTEM AT THE THREE WAY + OXIDATION CATALYTIC CONVERTER AND EXHAUST MANIFOLD REAR PIPE MATING SURFACES (2) IN A FORE TO AFT DIRECTION AND LISTEN FOR EXHAUST RATTLE COMING FROM WITHIN THE FLEX COUPLING.

4. IF EXHAUST RATTLE IS PRESENT WITHIN THE FLEX COUPLING, THE EXHAUST MANIFOLD REAR PIPE MUST BE REPLACED. EXHAUST MANIFOLD REAR PIPE UNITS ARE AVAILABLE WITH AN INTERNAL SINGLE PIECE SLEEVE WHICH WILL CORRECT THIS CONDITION.

5. IF THE EXHAUST SYSTEM RATTLES AND OR CONTACTS THE BODY OF THE VEHICLE, THE EXHAUST SYSTEM MUST BE ALIGNED ACCORDING TO THE EXHAUST SYSTEM ALIGNMENT PROCEDURE IN SECTION 6F OF THE 1996 E/K/K SPECIAL SERVICE INFORMATION MANUAL.

PARTS INFORMATION WHENEVER IT IS NECESSARY TO REPLACE THE EXHAUST MANIFOLD REAR PIPE, REFER TO THE FOLLOWING PART NUMBER:

DESCRIPTION PART NUMBER EXHAUST MANIFOLD REAR PIPE 3544526

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

#### WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION NUMBER: L2160 (REPLACE REAR PIPE) LABOR TIME: USE PUBLISHED LABOR OPERATION TIME.

LABOR OPERATION NUMBER: L2005 (EXHAUST SYSTEM ALIGNMENT) LABOR TIME: USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 1 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.