COLD ENGINE LIFTER TICK NOISE

SUBJECT: COLD ENGINE LIFTER TICK NOISE (MODIFY CAMSHAFT THRUST PLATE OILING)

MODELS: 1991-94 CHEVROLET LUMINA 1995 CHEVROLET LUMINA, MONTE CARLO BUILT PRIOR TO VIN BREAKPOINT S9148603 1991-94 PONTIAC GRAND PRIX 1991-94 OLDSMOBILE CUTLASS SUPREME WITH 3.4L DOHC V6 ENGINE (VIN X - RPO LQ1)

CONDITION:

SOME OWNERS MAY COMMENT ON A TICK TYPE NOISE ON A COLD ENGINE. THIS NOISE WILL BE PRESENT AFTER A MINIMUM OF A 2 HOUR COLD SOAK. THE ENGINE MAY BE QUIET ON THE INITIAL START FOR APPROXIMATELY 30-60 SECONDS, THEN THE TICK WILL APPEAR FOR 5-10 MINUTES AND THEN GOES AWAY AFTER THE ENGINE IS WARMED UP. THIS TICK NOISE WILL NOT BE HEARD ON A HOT RESTART. THIS NOISE IS NOT DETRIMENTAL TO THE DEPENDABILITY OR RELIABILITY OF THE ENGINE.

CAUSE:

LIFTER TICK NOISE IS A FUNCTION OF OIL TEMPERATURE. UNDER COLD CONDITIONS, HIGH OIL PRESSURE FLUCTUATIONS IN THE LIFTER GALLERY ARE UNSEATING THE INTERNAL LIFTER CHECK BALL WHICH ALLOWS THE LIFTER TO MOMENTARILY COLLAPSE. LIFTER GALLERY PRESSURE FLUCTUATIONS AT LOW SPEED VARY SIGNIFICANTLY WITH OIL TEMPERATURE. THUS, TICK NOISE IS DEPENDENT ON THE TIMING OF A RAPID OIL PRESSURE DROP IN THE LIFTER GALLERY.

CORRECTION:

AN OILING SCHEME IMPROVEMENT PACKAGE HAS BEEN DEVELOPED. FOR ENGINES PRODUCED AFTER AUGUST 23, 1994 THE IMPROVED SYSTEM WILL HAVE A CAMSHAFT WHICH WILL NOT HAVE THE THRUST PLATE GROOVE 4MM OILING HOLE. THE CUP PLUG IN THE CAMSHAFT WILL HAVE A 2MM HOLE TO OIL THE THRUST PLATE. BY RESTRICTING THE FLOW OF OIL FROM THE LIFTER GALLERY WITH A 2MM HOLE, IT IMPROVES OVERHEAD OIL PRESSURE AND DAMPENS THE OIL PULSATIONS OF COLD ENGINE OIL. THE OILING SCHEME IMPROVEMENT PACKAGE IS AVAILABLE AS A SERVICE REPAIR KIT, PART NUMBER 12538687. THE REPAIRS INVOLVE ELIMINATING THE 4MM THRUST PLATE GROOVE OIL HOLE, INSTALLING A NEW CUP PLUG WITH A 2MM HOLE IN THE END OF THE CAMSHAFTS AND A THINNER THRUST PLATE (FIGURE 1).

THE FOLLOWING SERVICE PROCEDURE IS APPLICABLE TO 1991-94 W CARS WITH THE 3.4L DOHC V6 ENGINE AND 1995 CHEVROLET LUMINA, MONTE CARLO BUILT PRIOR TO VIN S9148603.

REMOVE OR DISCONNECT

1. NEGATIVE BATTERY CABLE 2. AIR CLEANER 3. DRAIN ENGINE COOLANT 4. CONTROL CABLES FROM THROTTLE BODY OF UPPER INTAKE 5. FUEL RAIL COVER 6. PCV VALVE AND VACUUM LINE FROM THROTTLE BODY, VACUUM MODULATOR LINE AT INTAKE MANIFOLD 7. HEATER HOSE AT LOWER INTAKE MANIFOLD 8. ELECTRICAL CONNECTORS ON TPS, EGR, EVAPORATIVE EMISSION CANISTER PURGE SOLENOID, MAP 9. EGR BOLTS 10. EGR VALVE, SET ASIDE 11. FUEL LINE BRACKET AT THROTTLE BODY OF UPPER INTAKE 12. LOOSEN THROTTLE BODY HEATER HOSE CLAMP AT UPPER INTAKE MANIFOLD HEATER HOSE CLAMP AT UPPER INTAKE MANIFOLD 13. BOLTS AT VACUUM SOURCE MANIFOLD ASSEMBLY/MAP ON UPPER INTAKE MANIFOLD 14. REAR BANK SPARK PLUG WIRES 15. NUTS AT UPPER INTAKE MANIFOLD SUPPORT BRACKET 16. UPPER INTAKE MANIFOLD BOLTS 17. UPPER INTAKE MANIFOLD 18. COVER INTAKE RUNNERS WITH A SHOP TOWEL

CAM CARRIER THRUST PLATE REAR COVER RIGHT SIDE (REAR)

REMOVE OR DISCONNECT

19. CAM CARRIER REAR COVER MOUNTING BOLT/SCREW 20. CAM CARRIER REAR COVER AND GASKET 21. REMOVE THE CUP PLUGS IN THE END OF THE CAMSHAFTS BY PUNCHING A HOLE IN THE PLUG USING AN AWL. INSERT A LONG SCREW INTO THE HOLE AND USE A PRY DEVICE AGAINST THE SCREW HEAD TO REMOVE THE CUP PLUG (FIGURE 2). 22. REMOVE THE CAMSHAFT THRUST PLATE. 23. ROTATE ENGINE SO THAT THE OIL HOLES LOCATED IN THE THRUST PLATE GROOVE ARE FACING UP. 24. FABRICATE A CHIP TRAY BY FOLDING A 1 X 5 PIECE OF PAPER INTO A VEE SHAPE AND INSERT INTO THE END OF EACH CAMSHAFT. 25. DRILL BOTH CAMSHAFTS OIL HOLES (LOCATED IN THE THRUST PLATE GROOVE WITH A NUMBER 21 DRILL (.1590) BIT) (FIGURE 3). 26. USE A 10/32 TAP AND TAP BOTH OIL HOLES TO A DEPTH OF APPROXIMATELY 6MM, OR TAKE THE SET SCREW AND IF USING A TAPERED TAP, PLACE IT ON THE UNTAPPERED PORTION OF THE TAP AND MARK THE TAP WITH A PAINT PENCIL. IF USING A BOTTOMING TAP, SIMPLY MARK THE TAP THE LENGTH OF THE SET SCREW THUS SETTING YOUR DEPTH (FIGURE 4). IT IS NOT NECESSARY TO TAP THE COMPLETE HOLE, FOR YOU WANT TO LEAVE A SHOULDER FOR THE SET SCREW TO BOTTOM AGAINST. 27. EMERY CLOTH THE THRUST PLATE GROOVE AT THE OIL HOLE TO REMOVE ANY BURRS. 28. REMOVE THE CHIP TRAYS, USE A SPRAY CLEANER TO REMOVE EXCESS DEBRIS AND BLOW DRY WITH AIR. 29. RED LOCTITE(R) (GM PART NUMBER 12345493 OR EQUIVALENT) BOTH SET SCREWS AND INSERT INTO THE TAPPED OIL HOLES. 30. INSTALL THE NEW CAM THRUST PLATE PROVIDED WITH THE KIT, TIGHTEN BOLTS TO 10 N.M (89 LB IN.).

NOTICE: IT IS IMPORTANT THAT YOU CLEAN ALL DEBRIS FROM THE OIL PASSAGE HOLE, FAILURE TO DO SO COULD RESULT IN A PREMATURE ENGINE FAILURE.

31. INSTALL THE NEW CUP PLUGS PROVIDED WITH THE KIT INTO THE END OF THE CAMSHAFTS. ONE WAY OF DOING THIS IS TO PLACE THE CUP PLUG ONTO A SOCKET, USE A PAIR OF PLIERS TO GRIP THE SOCKET AND TAP THE SOCKET WITH A HAMMER TO SET THE CUP PLUG. THE PLUG WILL BOTTOM OUT ON A SHOULDER IN THE HOLE OF THE CAMSHAFT (FIGURE 5). 32. INSTALL A NEW COVER GASKET PROVIDED WITH THE KIT, TIGHTEN BOLTS TO 10 N.M (89 LB IN).

CAM CARRIER THRUST PLATE REAR COVER LEFT SIDE (FRONT)

REMOVE OR DISCONNECT

33. UPPER RADIATOR HOSE 34. EXHAUST CROSSOVER PIPE 35. HEATER PIPE ASSEMBLY FROM COOLANT PUMP TO UPPER INTAKE MANIFOLD 36. THERMOSTAT HOUSING 37. ENGINE TORQUE STRUT 38. ENGINE LIFT SUPPORT 39. CAM CARRIER REAR COVER MOUNTING BOLT/SCREW 40. CAM CARRIER REAR COVER AND GASKET 41.REMOVE THE CUP PLUGS IN THE END OF THE CAMSHAFTS BY PUNCHING A HOLE IN THE PLUG USING AN AWL. INSERT A LONG SCREW INTO THE HOLE AND USE A PRY DEVICE AGAINST THE SCREW HEAD TO REMOVE THE CUP PLUG (FIGURE 2). 42. REMOVE THE CAMSHAFT THRUST PLATE. 43. ROTATE ENGINE SO THAT THE OIL HOLES LOCATED IN THE THRUST PLATE GROOVE ARE FACING UP. 44. FABRICATE A CHIP TRAY BY FOLDING A 1 X 5 PIECE OF PAPER INTO A VEE SHAPE AND INSERT INTO THE END OF EACH CAMSHAFT. 45. DRILL BOTH CAMSHAFTS OIL HOLES (LOCATED IN THE THRUST PLATE GROOVE WITH A NUMBER 21 DRILL (.1590) BIT) (FIGURE 3). 46. USE A 10/32 TAP AND TAP BOTH OIL HOLES TO A DEPTH OF APPROXIMATELY 6MM, OR TAKE THE SET SCREW AND IF USING A TAPERED TAP, PLACE IT ON THE UNTAPPERED PORTION OF THE TAP AND MARK THE TAP WITH A PAINT PENCIL. IF USING A BOTTOMING TAP, SIMPLY MARK THE TAP THE LENGTH OF THE SET SCREW THUS SETTING YOUR DEPTH (FIGURE 4). IT IS NOT NECESSARY TO TAP THE COMPLETE HOLE, FOR YOU WANT TO LEAVE A SHOULDER FOR THE SET SCREW TO BOTTOM AGAINST. 47. EMERY CLOTH THE THRUST PLATE GROOVE AT THE OIL HOLE TO REMOVE ANY BURRS. 48. REMOVE THE CHIP TRAYS, USE A SPRAY CLEANER TO REMOVE EXCESS DEBRIS AND BLOW DRY WITH AIR. 49. RED LOCTITE(R) (GM PART NUMBER 12345493 OR EQUIVALENT) BOTH SET SCREW AND INSERT INTO THE TAPPED OIL HOLES. 50. INSTALL THE NEW CAM THRUST PLATE PROVIDED WITH THE KIT, TIGHTEN BOLTS TO 10 N.M (89 LB IN).

NOTICE: IT IS IMPORTANT THAT YOU CLEAN ALL DEBRIS FROM THE OIL PASSAGE HOLE, FAILURE TO DO SO COULD RESULT IN A PREMATURE ENGINE FAILURE.

51. INSTALL THE NEW CUP PLUGS PROVIDED WITH THE KIT INTO THE END OF THE CAMSHAFTS. ONE WAY OF DOING THIS IS TO PLACE THE CUP PLUG ONTO A SOCKET, USE A PAIR OF PLIERS TO GRIP THE SOCKET AND TAP THE SOCKET WITH A HAMMER TO SET THE CUP PLUG. THE PLUG WILL BOTTOM OUT ON A SHOULDER IN THE HOLE OF THE CAMSHAFT. 52. INSTALL NEW COVER GASKET PROVIDED IN KIT AND COVER, TIGHTEN BOLTS TO 10 N.M (89 LB IN).

INSTALL OR CONNECT

53. ENGINE LIFT SUPPORT, TIGHTEN BOLTS TO 70 N.M (52 LB FT) 54. ENGINE TORQUE STRUT 55. THERMOSTAT HOUSING TO INLET MANIFOLD, BOLTS TO HOUSING WITH RTV SEALER GM PART NUMBER 1052366 OR EQUIVALENT, TIGHTEN BOLTS TO 25 N.M (18 LB FT). 56. HEATER PIPE ASSEMBLY FROM COOLANT PUMP TO UPPER INTAKE MANIFOLD, TIGHTEN BOLT TO 11 N.M (92 LB IN) NUT TO 25 N.M (18 LB FT). 57. EXHAUST CROSSOVER PIPE, TIGHTEN NUTS TO 25 N.M (18 LB FT). 58. UPPER RADIATOR HOSE 59. UPPER INTAKE MANIFOLD, GASKET AND O RING PROVIDED IN KIT 60. UPPER INTAKE MANIFOLD BOLTS, TIGHTEN TO 30 N.M (22 LB FT). 61. NUTS AT UPPER INTAKE MANIFOLD SUPPORT BRACKET, TIGHTEN TO 30 N.M (22 LB FT). 62. REAR BANK SPARK PLUG WIRES 63. BOLTS AT VACUUM SOURCE MANIFOLD ASSEMBLY/MAP ON UPPER INTAKE, TIGHTEN BOLTS TO 5 N.M (45 LB IN.). 64. TIGHTEN THROTTLE BODY HEATER HOSE CLAMP AT UPPER INTAKE. 65. FUEL LINE BRACKET AT THROTTLE BODY OF UPPER INTAKE 66. EGR VALVE AND GASKETS PROVIDED IN KIT, TIGHTEN BOLTS TO 27 N.M (20 LB FT). 67. ELECTRICAL CONNECTORS ON TPS, EGR, EVAPORATIVE EMISSION CANISTER PURGE SOLENOID, MAP 68. PCV VALVE AND VACUUM LINE AT THROTTLE BODY OF UPPER INTAKE, VACUUM MODULATOR LINE AT INTAKE MANIFOLD 69. FUEL RAIL COVER, TIGHTEN BOLTS 10 N.M (89 LB IN). 70. CONTROL CABLES AT THROTTLE BODY OF UPPER INTAKE 71. REFILL COOLANT (SEE SERVICE MANUAL SECTION 6B) 72. AIR CLEANER 73. NEGATIVE BATTERY CABLE

PART INFORMATION:

PARTS ARE EXPECTED TO BE AVAILABLE ON NOVEMBER 13, 1995 FROM GMSPO.

PART NUMBER NAME QUANTITY

12538687 REPAIR KIT - CAMSHAFT 1

THE KIT WILL CONSIST OF THE FOLLOWING PARTS:

NAME QUANTITY

THRUST PLATE - CAMSHAFT 2

GASKET - CAM CARRIER REAR COVER 2

CUP PLUG - CAMSHAFT 4

GASKET - UPPER INTAKE 1

SEAL - UPPER INTAKE 1

SET SCREW 5 (INCLUDES 1 EXTRA)

GASKET - EGR (ADAPTER TO MANIFOLD) 1

GASKET - EGR (ADAPTER TO EGR) 1

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION : J0032 LABOR TIME: 3.3 HRS

FIGURES: 5 ATTACHMENTS: 0

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 1995. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.