GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Remove the timing chain housing. Refer to Timing Chain Housing Replacement .
  3. Remove the spark plugs in order to make rotating the crankshaft to line up the timing marks easier.

  4. Object Number: 466546  Size: SH

    Important: The timing marks must be correctly aligned before disassembly.

  5. Rotate the crankshaft so that the following conditions are met:
  6. • The number 1 (frontmost) cylinder is at the top dead center (TDC) position on the compression stroke.
    • The keyway on the crankshaft (5) aligns with the mark on the engine block (4).
    • The arrow (3) on the idler sprocket is pointing upward.
    • The guide pins (1) on the camshaft sprockets line up with the notches (6) on the cylinder head.

    Object Number: 464755  Size: SH

    Important: Do not turn the crankshaft or camshaft once the tensioner is removed.

  7. Remove the 2 bolts (1) and the crankshaft timing chain tensioner.
  8. Inspect that the latch and teeth of the crankshaft timing chain tensioner are undamaged and that the tensioner functions correctly.

Installation Procedure


    Object Number: 464753  Size: SH
  1. Hold back the latch, compress the plunger and install a retainer (a paper clip or similar tool) to hold the plunger in place.

  2. Object Number: 464755  Size: SH

    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.

  3. Install the timing chain tensioner.
  4. Tighten
    Tighten the 2 bolts (1) to 11 N·m (97 lb in).

  5. Remove the retainer.

  6. Object Number: 466546  Size: SH
  7. Turn the crankshaft 2 revolutions realigning the keyway on the crankshaft (5) with the timing mark on the engine block (4).
  8. Ensure that the guide pins on the camshafts (1) are in line with the notches on the cylinder head (6).
  9. Apply engine oil to the following:
  10. • The timing chains
    • The tensioner
    • The guides
    • The sprockets
  11. Install the spark plugs.
  12. Tighten
    Tighten the spark plugs to 25 N·m (18 lb ft).

  13. Install the timing chain housing. Refer to Timing Chain Housing Replacement .
  14. Connect the negative battery cable.