MISDIAGNOSED POWER STEERING PUMP NOISE (DIAG. PROCEDURE)

SUBJECT: MISDIAGNOSED POWER STEERING PUMP NOISE (DIAGNOSTIC PROCEDURE)

MODELS: 1992-93 CHEVROLET AND GMC TRUCK C/K, S/T MODELS 1992-93 OLDSMOBILE BRAVADA WITH 4.3L, 5.0L, 5.7L ENGINES (RPOS LB4, L35, L03, L05)

CONDITION:

SOME OWNERS MAY COMMENT ON A WHINE NOISE EMANATING AT THE FRONT OF THE VEHICLE. AT FIRST GLANCE, THIS NOISE MAY APPEAR TO BE EMANATING FROM THE POWER STEERING PUMP. HOWEVER, THE NOISE MAY ACTUALLY BE THE RESULT OF A FAILED BEARING IN THE GENERATOR. THE DIAGNOSTIC PROCEDURE BELOW DESCRIBES A PROCEDURE WHICH WILL ENABLE THE POWER STEERING PUMP TO BE OPERATED INDEPENDENTLY OF THE GENERATOR. THIS PROCEDURE SHOULD BE USED AS A DIAGNOSTIC AID WHEN SEARCHING FOR THE ROOT CAUSE OF A FRONT ACCESSORY DRIVE NOISE.

DIAGNOSIS/CORRECTION:

BEFORE REPLACING ANY COMPONENTS, FOLLOW THE DIAGNOSIS PROCEDURE BELOW IN ORDER TO ISOLATE THE POWER STEERING PUMP FROM THE GENERATOR.

1. ISOLATE THE POWER STEERING PUMP FROM THE GENERATOR BY INSTALLING AN ACCESSORY DRIVE BELT OFF OF A 3.4L EQUIPPED 1993 OR 1994 CAMARO/FIREBIRD (P/N 10243486). INSTALL THE DIAGNOSIS BELT AS SHOWN IN FIGURE 1.

2. RUN THE ENGINE AND LISTEN FOR THE NOISE. DO NOT DRIVE THE VEHICLE WITH THIS BELT ATTACHED.

- IF THE NOISE IS GONE, THE POWER STEERING SYSTEM IS MOST LIKELY AT FAULT. REFER TO BULLETIN NUMBER 383001 DATED DECEMBER, 1993 WHICH DETAILS A REVISED STEERING SYSTEM BLEED PROCEDURE WHICH SHOULD BE USED FOR CASES OF STEERING SYSTEM NOISE.

- IF THE NOISE REMAINS, PROCEED TO DIAGNOSE THE REMAINING ELEMENTS OF THE ACCESSORY DRIVE INCLUDING THE GENERATOR.

3. AFTER THE NOISE IS SUCCESSFULLY CORRECTED, REMOVE THE ACCESSORY DRIVE BELT USED FOR DIAGNOSIS.

4. INSTALL THE ORIGINAL ACCESSORY DRIVE BELT AS SHOWN IN FIGURE 2.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME

J0667 DRIVE BELT, R + R TWICE .2 HRS.

FIGURES: 2

CAPTIONS:

FIGURE 1 - BELT ROUTING TO ISOLATE POWER STEERING PUMP FROM THE ACCESSORY DRIVE FIGURE 2 - PRODUCTION BELT ROUTING FOR 4.3L/5.0L/5.7L ENGINES

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.