RATTLING NOISE ENGINE OVER HEATING. Buick Skylark 1988

REVISION: 01/05/95

THIS BULLETIN IS BEING REVISED TO REMOVE THE W CAR. PLEASE DISCARD BULLETIN 47-61-47 (SECTION 6 - ENGINE). ----------------------------------------------------------------------

SUBJECT: RATTLING NOISE/ENGINE OVERHEATING (REPLACE IDLER SPROCKET AND BEARING)

MODELS: 1988 BUICK SKYLARK 1987-88 OLDSMOBILE CALAIS 1988 PONTIAC GRAND AM WITH 2.3L ENGINE (VIN D - RPO LD2)

CONDITION:

SOME CUSTOMERS MAY COMMENT ON A RATTLING NOISE EMANATING FROM THE FRONT COVER AREA OF THE ENGINE AND/OR LACK OF COOLING CAPABILITY OF THE ENGINE.

CAUSE:

THE TIMING CHAIN IDLER SPROCKET ON SOME ENGINES WAS MANUFACTURED WITHOUT THE 4MM HOLE IN THE CENTER OF THE IDLER SPROCKET ASSEMBLY. THIS HOLE IS NECESSARY FOR ADEQUATE LUBRICATION AT SPROCKET TO COOLANT PUMP SPLINE CONNECTION. WITHOUT THE NECESSARY LUBRICATION, SPLINE WEAR OCCURS ON THE SPROCKET SPLINES AND POSSIBLY THE SPLINES ON THE COOLANT PUMP SHAFT.

CORRECTION:

IF ABOVE CONDITIONS EXIST, REMOVE TIMING CHAIN FRONT COVER AND INSPECT FOR 4MM HOLE LOCATED DIRECTLY IN THE CENTER OF THE TIMING CHAIN IDLER SPROCKET (SEE FIGURE). IF HOLE IS NOT PRESENT, REMOVE TIMING CHAIN HOUSING ASSEMBLY AS INSTRUCTED IN SERVICE PROCEDURE AND REPLACE IDLER SPROCKET AND BEARING. THE COOLANT PUMP MUST ALSO BE INSPECTED FOR SHAFT SPLINE DAMAGE AND REPLACED IF NECESSARY.

SERVICE PROCEDURE

REMOVE OR DISCONNECT

1. ENGINE FRONT COVER. REFER TO "ENGINE FRONT COVER" IN SECTION 6A7 OF THE SERVICE MANUAL. 2. CHECK FOR PRESENCE OF 4MM HOLE IN CENTER OF TIMING CHAIN IDLER SPROCKET. IF HOLE IS NOT PRESENT, PROCEED WITH REPLACEMENT OF SPROCKET AND BEARING ASSEMBLY. 3. TIMING CHAIN HOUSING. REFER TO "TIMING CHAIN HOUSING" IN SECTION 6A7 OF THE SERVICE MANUAL. 4. TIMING CHAIN IDLER SPROCKET AND BEARING. REFER TO "TIMING CHAIN IDLER SPROCKET AND BEARING" IN SECTION 6A7 OF THE SERVICE MANUAL. IMPORTANT: ANY TIME THE TIMING CHAIN IDLER SPROCKET IS PRESSED OUT OF THE BEARING, THE BEARING MUST BE REPLACED. THE BEARING IS DAMAGED DURING THE PRESSING OPERATION.

INSPECT

1. COOLANT PUMP FOR DAMAGE TO SPLINES ON COOLANT PUMP DRIVE SHAFT. IF COOLANT PUMP OR DRIVE SHAFT IS DAMAGED, REPLACE PUMP. REFER TO "COOLANT PUMP" REPLACEMENT PROCEDURE IN SECTION 6B OF THE SERVICE MANUAL.

CLEAN

ALL GASKET MATING SURFACES.

INSTALL OR CONNECT

1. COOLANT PUMP, IF IT WAS REPLACED DUE TO SHAFT SPLINE DAMAGE. REFER TO "COOLANT PUMP" IN SECTION 6B OF THE SERVICE MANUAL. 2. TIMING CHAIN IDLER SPROCKET AND BEARING. REFER TO "TIMING CHAIN IDLER SPROCKET AND BEARING" IN SECTION 6A7 OF THE SERVICE MANUAL. 3. TIMING CHAIN HOUSING. REFER TO "TIMING CHAIN HOUSING" IN SECTION 6A7 OF THE SERVICE MANUAL. 4. FILL COOLANT, AS NECESSARY. 5. CHECK OIL LEVEL AND FILL AS NECESSARY. 6. START ENGINE AND CHECK FOR LEAKS.

PARTS INFORMATION:

PART NUMBER PART DESCRIPTION ****************************************************** * 22537881 SPROCKET, TIMING CHAIN IDLER * * 24571389 PUMP, COOLANT * * 12353643 GASKET KIT, COOLANT PUMP * * 908468 BEARING, TIMING CHAIN IDLER SPRKT.* ******************************************************

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

LABOR TIME INFORMATION:

LABOR OPERATION LABOR TIME ******************************************************* * JO844 IDLER SPROCKET AND/OR BEARING, 3.2 * * TIMING CHAIN - REPLACE * * ADD A: WITH LOCKING WHEEL COVERS/NUTS 0.1 * * (SUBMIT AS REGULAR LABOR HOURS) * * ADD B: TO CLEAN PARTS ON VEHICLES OVER 0.2 * * 30,000 MILES, IF NECESSARY * * (SUBMIT AS REGULAR LABOR HOURS) * * J3480 PUMP AND/OR GASKET, COOLANT - 1.4 * * REPLACE * *******************************************************

FIGURES: 1 ATTACHMENTS: 0

Object Number: 82859 Size: FS

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