GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Important: If the timing chain, timing gears, front cover, crankshaft position sensor, crankshaft or other components affecting timing are replaced, it will be necessary to reprogram TDC Offset into the PCM. Refer to Engine Controls for the proper service procedures.


    Object Number: 346972  Size: SH
  1. Disconnect the battery negative cables from the batteries. Refer to Battery Cable Replacement in Engine Electrical.
  2. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  3. Remove the fan shrouds from the radiator. Refer to Fan Shroud Replacement in Engine Cooling.
  4. Remove the drive belt from the vehicle. Refer to Drive Belt Replacement .
  5. Remove the crankshaft balancer from the crankshaft. Refer to Crankshaft Balancer Replacement .
  6. Remove the engine front cover from the engine block. Refer to Engine Front Cover Replacement .

  7. Object Number: 59876  Size: SH
  8. Remove the timing chain sprocket/fuel injection pump drive gear, from the camshaft.

  9. Object Number: 59879  Size: SH
  10. Remove the crankshaft sprocket from the crankshaft.

Installation Procedure

Important: If the timing chain, timing gears, front cover, crankshaft position sensor, crankshaft or other components affecting timing are replaced, it will be necessary to reprogram TDC Offset into the PCM. Refer to Engine Controls for the proper service procedures.


    Object Number: 59879  Size: SH
  1. Install the crankshaft sprocket to the crankshaft.

  2. Object Number: 59876  Size: SH
  3. Install the timing chain sprocket and chain to the camshaft.

  4. Object Number: 59874  Size: SH
  5. Install the fuel injection pump drive gear to the camshaft.

  6. Object Number: 59872  Size: SH
  7. Install the camshaft bolt to the camshaft.
  8. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  9. Install the bolt and the washer for the camshaft gear.
  10. Tighten
    Tighten the bolt for the camshaft gear to 171 N·m (126 ft lb).

  11. Install the engine front cover to the engine block. Refer to Engine Front Cover Replacement .
  12. Install the crankshaft balancer to the crankshaft. Refer to Crankshaft Balancer Replacement .
  13. Install the drive belt on the pulleys. Refer to Drive Belt Replacement .
  14. Install the fan shrouds to the radiator. Refer to Fan Shroud Replacement in Engine Cooling.
  15. Connect the battery negative cables to the batteries. Refer to Battery Cable Replacement in Engine Electrical.
  16. Perform the TDC offset timing procedure. Refer to Fuel Injection Pump Top Dead Center Offset Adjustment in Engine Controls-6.5L-L65.