EXHAUST MOAN/BOOM (INSTALL DAMPENER)

SUBJECT: EXHAUST MOAN/BOOM (INSTALL DAMPENER)

MODELS: 1994-95 BUICK ROADMASTER 1994-95 CHEVROLET CAPRICE CLASSIC AND IMPALA SUPER SPORT WITH 5.7L V8 ENGINE (VIN P - RPO LT1)

CONDITION:

SOME CUSTOMERS MAY COMMENT ON AN EXHAUST MOAN/BOOM EVIDENT WHEN THE ENGINE IS OPERATED AT APPROXIMATELY 1,200 RPM. THIS CONDITION IS MOST APPARENT AT LOWER AMBIENT TEMPERATURES AFTER A COLD START.

CAUSE:

VEHICLE EXHAUST SYSTEM EXCITATION CAUSED BY ENGINE EXHAUST PULSE INDUCED VIBRATION.

CORRECTION:

INSTALL DAMPENER TO LH CATALYTIC CONVERTER FLANGE USING COMPONENTS AND SERVICE PROCEDURE INDICATED BELOW:

COMPONENTS REQUIRED

DESCRIPTION P/N QUANTITY

DAMPENER 10272298 1 BOLT 3522364 2 WASHER 3790768 2 NUT 10255857 2

SERVICE PROCEDURE:

1. RAISE AND SUITABLY SUPPORT VEHICLE.

2. LOCATE AND ENLARGE THE TWO HOLES OF THE LH CATALYTIC CONVERTER ATTACHING FLANGE SHOWN IN FIGURE 1 UTILIZING A 25/64" DRILL BIT.

3. USING AN AIR HAMMER AND CHISEL BIT OR DIE GRINDER, REMOVE REMAINING RAISED BOSS FROM AROUND HOLES THAT WERE ENLARGED IN STEP TWO (2).

4. INSTALL DAMPENER, P/N 10272298, AS SHOWN IN FIGURE 2 AND SECURE IN POSITION USING TWO (2) BOLTS, P/N 3522364, TWO (2) WASHERS, P/N 3790768 AND TWO (2) NUTS, P/N 10255857.

5. HOLDING BOLTS WITH A BACK-UP WRENCH, TORQUE NUTS TO 50 N.M (37 LB. FT.).

6. LOWER VEHICLE.

PART AVAILABILITY:

PARTS WILL BE AVAILABLE FROM GMSPO ON OCTOBER 10, 1994.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE: LABOR OPERATION: L2008 LABOR TIME: 0.3 HR.

FIGURES: 2

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 1994 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.