A/C COMPRESSOR MOAN NOISE UNDER LIGHT ACCELERATION. Cadillac Concours 1994

For 1990-2009 cars

# A/C COMPRESSOR MOAN NOISE UNDER LIGHT ACCELERATION

REVISION: 05/31/96

THIS BULLETIN IS BEING REVISED TO INCLUDE THE 1992-93 E/K MODELS. PLEASE DISCARD CORPORATION BULLETIN NUMBER 43-12-25 (SECTION 1- HVAC). **********************************************************************

#### SUBJECT: A/C COMPRESSOR MOAN NOISE UNDER LIGHT ACCELERATION (REPLACE A/C COMPRESSOR HOSE ASSEMBLY AND CLUTCH DRIVER)

#### MODELS: 1992-93 CADILLAC ELDORADO, SEVILLE 1994 CADILLAC DEVILLE

#### ENGINE APPLICATIONS:

1992 4.9L VIN B - RPO L26

1993 4.6L VINS Y, 9 - RPOS LD8, L37 4.9L VIN B - RPO L26

1994 4.9L VIN B - RPO L26

#### CONDITION:

SOME OWNERS MAY COMMENT ON AN A/C COMPRESSOR MOAN NOISE THAT BECOMES EVIDENT UNDER LIGHT ACCELERATION WHEN THE A/C COMPRESSOR CLUTCH IS ENGAGED. THIS CONDITION IS MORE LIKELY TO EXIST IN HIGH AMBIENT TEMPERATURE/HUMIDITY AND BE MOST REPEATABLE UNDER LIGHT ACCELERATION BETWEEN 1400 AND 2100 ENGINE RPM.

#### CAUSE:

THE COMPRESSOR HOSE ASSEMBLY TRANSMITS THE COMPRESSOR PUMPING PULSES INTO THE BODY. THE MATERIAL OF THE COMPRESSOR HOSE DOES NOT PROVIDE SUFFICIENT DAMPENING CAUSING THE TRANSMITTAL OF THESE NOISES.

#### CORRECTION:

TO DETERMINE THE CORRECT CAUSE OF THE MOAN NOISE, THE FOLLOWING STEPS MUST BE FOLLOWED:

1. CHECK THE TORQUE OF THE MOUNTING BRACKET TO ENGINE. CHECK THE TORQUE OF THE A/C COMPRESSOR TO THE MOUNTING BRACKET.

2. CHECK THAT NO A/C HOSES ARE TOUCHING OTHER COMPONENTS. COMMON GROUND POINTS ARE:

- LOW SIDE TO RIGHT STRUT TOWER - LOW SIDE TO BATTERY TRAY OR ROUTING CLIP - HIGH SIDE TO ABS VALVE ASSEMBLY - CONDENSER INLET OR OUTLET PIPES TO RADIATOR, BODY OR WIRE HARNESS - HIGH SIDE TO PLASTIC COVER (DRIVER'S SIDE UNDERHOOD) - HIGH SIDE TO BODY WIRE HARNESS NEAR BRAKE BOOSTER

3. REPLACE THE A/C COMPRESSOR HOSE ASSEMBLY WITH NEW HOSE (SEE BELOW FOR P/N). THE HOSE MATERIAL USED IN THIS ASSEMBLY IS SOFTER. REFER TO SECTION 1B OF THE SERVICE MANUAL FOR REPLACEMENT PROCEDURE.

4. REPLACE THE A/C COMPRESSOR CLUTCH DRIVER WITH THE DAMPENED TYPE USING KIT, P/N 6553791. REFER TO SECTION 1D2 OF THE SERVICE MANUAL FOR REPLACEMENT PROCEDURE.

#### IMPORTANT: THIS CLUTCH MUST BE CYCLED 50 TIMES TO ASSURE OPTIMAL PERFORMANCE.

#### PARTS INFORMATION:

A/C COMPRESSOR MODEL YEAR HOSE ASSM. P/N USAGE ========== ============== =====

1992 25655631 4.9L 1993 25655632 4.9L 1993 25655633 4.6L 1994 3542985 4.9L

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

#### WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

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

D4237 BRACKET(S), COMPRESSOR 0.3 HR MOUNTING R&R OR REPLACE (ALL) (STEPS 1 & 2)

ADD TO INSPECT A/C HOSES 0.1 HR

D3088 COMPRESSOR SUCTION AND USE PUBLISHED DISCHARGE HOSE ASSEMBLY - LABOR TIME REPLACE (STEP 3)

D4240 CLUTCH PLATE AND HUB USE PUBLISHED ASSEMBLY, COMPRESSOR - LABOR TIME REPLACE (STEP 4)

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.