ACCESSORY DRIVE NOISE (FOLLOW DIAG. PROC.)

SUBJECT: ACCESSORY DRIVE NOISE (FOLLOW DIAGNOSTIC PROCEDURES)

MODELS: 1998 CADILLAC DEVILLE, ELDORADO, SEVILLE, COMMERCIAL CHASSIS 1998 OLDSMOBILE AURORA WITH 4.0L OR 4.6L ENGINE (VINS C, Y, 9 - RPOS L47, LD8, L37) BUILT PRIOR TO FEBRUARY 1, 1998

CONDITION:

SOME OWNERS MAY COMMENT ABOUT CHIRPING, TICKING, KNOCKING, OR "TRASHY" NOISES FROM THE FRONT OF THE ENGINE. THE SERVICE WRITER AND TECHNICIAN SHOULD NOTE IN WRITING ON THE REPAIR ORDER THE CONDITIONS ASSOCIATED WITH THE NOISE SUCH AS OUTSIDE AMBIENT AND ENGINE OPERATING TEMPERATURES, AND WHEN THE NOISE IS OBSERVED. THE SERVICE WRITER SHOULD PERSONALLY OBSERVE AND DESCRIBE THE TYPE AND LOCATION OF NOISE ON THE REPAIR ORDER. THE NOISE MAY SOUND LIKE AN UNDER HOOD SQUEAK, A METALLIC TRASHY NOISE, OR AN INSIDE VEHICLE THUMP, ETC. THE SERVICE WRITER SHOULD ASK THE OWNER IF THE NOISE OCCURS FOLLOWING START UP AFTER AN OVERNIGHT SOAK, AND WHETHER THE NOISE REDUCES OR GOES AWAY COMPLETELY AS THE ENGINE WARMS UP. WRITE THE CUSTOMER RESPONSE ON THE SERVICE REPAIR ORDER.

CAUSE:

THIS CONDITION MAY BE CAUSED BY PULLEY MISALIGNMENT OF THE ACCESSORY DRIVE SYSTEM.

CORRECTION:

THE CORRECTIVE PROCEDURE BELOW HAS BEEN DEVELOPED FOR THE 4.0L AND 4.6L ENGINES IDENTIFIED ABOVE, AND CAN BE USED TO SERVICE 4.0L AND 4.6L ENGINES EXHIBITING THESE NOISES. IF A VEHICLE IS ENCOUNTERED WITH ANY OF THE ABOVE CONCERNS AND THE CONDITION IS STILL PRESENT AFTER COMPLETING ALL OF THE DIAGNOSTIC PROCEDURES LISTED IN THE SERVICE MANUAL, THEN PERFORM THE FOLLOWING PROCEDURE:

1. CHECK POWER STEERING FLUID LEVEL AND ADD FLUID IF NECESSARY.

2. START VEHICLE AND RUN FOR THREE (3) MINUTES, IDLING IN PARK WITH THE HOOD OPEN.

3. WHILE THE ENGINE IS RUNNING, VERIFY THE TYPE AND LOCATION OF NOISE DESCRIBED BY THE CUSTOMER. IT MAY BE NECESSARY TO INCREASE THE ENGINE SPEED UP TO APPROXIMATELY 2,500 RPM AND CLOSELY LISTEN FOR NOISE.

4. REMOVE THE ACCESSORY DRIVE BELT AND INSPECT THE BELT GROOVES FOR DAMAGE AND PILLING (FIGURE 1). PILLING APPEARS AS SHINY AREAS IN THE GROOVES OF THE ACCESSORY DRIVE BELT. COMPLETELY DESCRIBE ANY BELT DAMAGE OR PILLING OBSERVED ON THE REPAIR ORDER. TAG THE REMOVED BELT WITH ALL PERTINENT PART RETURN INFORMATION AND RETURN IT TO THE WARRANTY PARTS CENTER.

5. START THE VEHICLE AND LISTEN FOR NOISE. IF THE NOISE IS STILL PRESENT, THE SOURCE IS NOT THE BELT OR ACCESSORY DRIVE COMPONENTS, FOLLOW THE ENGINE MECHANICAL NOISE DIAGNOSIS SECTION OF THE APPLICABLE SERVICE MANUAL. IF THE NOISE IS NO LONGER PRESENT, PROCEED TO THE NEXT STEP OF THIS PROCEDURE.

6. INSPECT THE ACCESSORY DRIVE PULLEYS FOR DAMAGE SUCH AS CHIPS, DINGS, DENTS, OR UNCOMMON WEAR PATTERNS. CHECK ALL PULLEYS FOR TRUENESS OR UNUSUAL WEAR. TO DETERMINE TRUENESS, ROTATE THE PULLEY AND COMPARE THE VERTICAL SURFACE TO A FIXED POINT USING A MEASURING DEVICE. IF THE MEASURED DISTANCE BETWEEN THE TWO POINTS REMAINS CONSTANT, THE PULLEY IS RUNNING TRUE; IF THE DISTANCE VARIES, THE PULLEY IS NOT RUNNING TRUE. REPLACE ANY ACCESSORY DRIVE PULLEYS WHICH ARE NOT TRUE, DAMAGED OR WORN.

7. REMOVE THE POWER STEERING PUMP AND BRACKET AND PLACE IN A SHOP VISE (FIGURE 2). INSPECT THE POWER STEERING PULLEY FOR CRACKS, CHIPS AND EXCESSIVE RUNOUT. REPLACE ANY DAMAGED PULLEYS.

8. REMOVE ANY FLASH FROM THE MOLD PARTING LINES IN THE BELT CONTACT AREA OF THE POWER STEERING PUMP PULLEY (FIGURE 3). FLASH CAN BE DETECTED BY RUNNING YOUR FINGER NAIL PERPENDICULAR TO THE GROOVES IN THE PULLEY. USE A PIECE OF 400 GRIT SANDPAPER FOLDED INTO A "V" OR A SMALL SMOOTH FILE TO REMOVE ALL FLASH FROM THE ENTIRE BELT CONTACT AREA OF THE POWER STEERING PUMP PULLEY. CONTINUE TO SAND THE PULLEY UNTIL THE FLASH CAN NO LONGER BE DETECTED IN THE ENTIRE BELT CONTACT AREA BY RUNNING YOUR FINGER NAIL PERPENDICULAR TO THE GROOVES IN THE PULLEY. THOROUGHLY CLEAN THE PULLEY WITH SHOP AIR AND A CLEAN SHOP TOWEL AFTER REMOVING THE FLASH.

9. REMOVE THE DUST CAP AND CHECK THE POWER STEERING PUMP PULLEY TO SHAFT FLUSHNESS WITH A STRAIGHT EDGE (FIGURE 4). IF NECESSARY, ADJUST THE PULLEY SO IT IS FLUSH WITH THE POWER STEERING PUMP SHAFT USING PULLEY INSTALLER TOOL J25033-B, AND REMOVER TOOL J38825.

10.FILE A CHAMFER ON THE FRONT FACE OF ENGINE BLOCK WHERE THE POWER STEERING PUMP MOUNTING BRACKET LOCATING PAD IS LOCATED SO THAT THE SHARP CORNER HAS BEEN ELIMINATED (FIGURE 5). DO NOT FILE THE POWER STEERING PUMP MOUNTING BRACKET.

11.REINSTALL THE POWER STEERING PUMP AND BRACKET ASSEMBLY, MAKING SURE TO PUSH AND HOLD THE PUMP TOWARD THE REAR OF THE ENGINE WHILE TIGHTENING THE ATTACHING BOLT. (THE PROPER TORQUE FOR THE BOLT IS 50 NM (37 LB FT). VERIFY THAT THERE IS NO GAP BETWEEN THE POWER STEERING PUMP BRACKET LOCATING EAR AND THE ENGINE BLOCK (FIGURE 6). ADD POWER STEERING FLUID AS NECESSARY TO FILL THE POWER STEERING SYSTEM.

12.INSTALL THE APPROPRIATE NEW ACCESSORY DRIVE BELT FOR THE VEHICLE BEING SERVICED AS SPECIFIED IN THE PARTS INFORMATION SECTION OF THIS BULLETIN.

13.START THE ENGINE AND VERIFY THAT ALL COMPONENTS REMOVED HAVE BEEN REASSEMBLED PROPERLY.

14.CHECK POWER STEERING FLUID LEVEL, AND ADD FLUID IF NECESSARY.

15.RETURN VEHICLE TO CUSTOMER.

PARTS INFORMATION:

WHEN PERFORMING THIS OPERATION USE THE FOLLOWING INFORMATION:

PART NUMBER DESCRIPTION 12555239 ACCESSORY DRIVE BELT--SEVILLE ONLY

12560973 ACCESSORY DRIVE BELT--CADILLAC EXCEPT DEVILLE WITHOUT KG9 OPTION AND SEVILLE

12560974 ACCESSORY DRIVE BELT--CADILLAC WITH KG9 OPTION

12561088 ACCESSORY DRIVE BELT--OLDSMOBILE AURORA

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR LABOR OPERATION DESCRIPTION TIME --------- ----------- ----

T2267 ACCESSORY DRIVE 1.3 HRS (E/K CARS) SERVICE 1.6 HRS (G CARS)

FIGURES: 6 ATTACHMENTS: 0

NOTE: FOR STG PUBLICATIONS ONLY THE ART USED IN THIS BULLETIN HAS BEEN PREVIOUSLY USED IN BULLETIN NUMBER 77-61-19 DATED NOVEMBER, 1997. THE S.I.E. NUMBERS FOR THE ART ASSOCIATED WITH THIS BULLETIN ARE AS FOLLOWS:

FIGURE 1 GPENGINE01.DG FIGURE 2 GPENGINE02.DG FIGURE 3 GPENGINE03.DG FIGURE 4 GPENGINE04.DG FIGURE 5 GPENGINE05.DG FIGURE 6 GPENGINE06.DG

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.

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