For 1990-2009 cars

# A/C COMPRESSOR 'MOAN' NOISE AT 2100 RPM

#### SUBJECT: A/C COMPRESSOR "MOAN" NOISE AT 2100 RPM (REPLACE A/C COMPRESSOR CLUTCH PLATE AND HUB ASSEMBLY)

#### MODELS: 1993-95 CHEVROLET LUMINA APV 1993-95 OLDSMOBILE SILHOUETTE 1993-95 PONTIAC TRANS SPORT WITH 3.8L ENGINE (VIN L - RPO L27)

#### CONDITION:

SOME OWNERS MAY COMMENT ON A "MOAN" TYPE NOISE THAT BECOMES EVIDENT UNDER LIGHT ACCELERATION WHEN THE A/C COMPRESSOR CLUTCH IS ENGAGED. THIS CONDITION IS PREVALENT WHEN DRIVING AT OR AROUND 2100 RPM AND MORE NOTICEABLE IN HIGH AMBIENT TEMPERATURES AND/OR HUMIDITY.

#### CAUSE:

THE "MOAN" NOISE MAY BE CREATED BY COMPRESSOR PULSES WHICH SET UP A SYSTEM RESONANCE.

#### CORRECTION:

REPLACE THE A/C COMPRESSOR CLUTCH PLATE AND HUB ASSEMBLY, P/N 6553791, AS IDENTIFIED IN THE PROCEDURE IN SECTION 1D2 OF THE SERVICE MANUAL. THE REPLACEMENT OF THE CLUTCH PLATE AND HUB ASSEMBLY WILL IMPROVE THE CONDITION CONSIDERABLY; HOWEVER, BECAUSE OF VARIOUS BUILD CONFIGURATIONS WHICH ARE CRITICAL TO SYSTEM MOAN, IT MAY NOT TOTALLY REMOVE ALL OF THE MOAN ON SOME VEHICLES.

#### PARTS INFORMATION:

P/N DESCRIPTION QUANTITY === =========== ========

6553791 CLUTCH DRIVER, COMPRESSOR 1

PARTS ARE EXPECTED TO BE AVAILABLE ON SEPTEMBER 2, 1996.

#### WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION NUMBER DESCRIPTION LABOR TIME =============== =========== ==========

D4240 CLUTCH PLATE AND HUB ASSEMBLY, USE PUBLISHED COMPRESSOR - REPLACE LABOR 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.

COPYRIGHT 1996 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.