GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 22102 Front Cover Aligner and Seal installer
    • J 42846 Crankshaft Protector Button

Removal Procedure


    Object Number: 470814  Size: SH
  1. Remove the engine front cover. Refer to Engine Front Cover Replacement .
  2. Align the timing marks on the camshaft and crankshaft sprockets.
  3. Remove the camshaft sprocket bolts.
  4. Remove the camshaft sprocket and timing chain.

  5. Object Number: 639535  Size: SH
  6. Install the J 42846 (1) into the end of the crankshaft.
  7. Remove the crankshaft sprocket using a suitable three jaw puller.
  8. Clean and inspect the timing chain and sprockets. Refer to Camshaft Timing Chain and Sprocket Cleaning and Inspection in Engine Mechanical - 8.1L Unit Repair.

Installation Procedure


    Object Number: 65850  Size: SH
  1. Use the J 22102 in order to install the crankshaft sprocket.
  2. Align the keyway of the sprocket with the crankshaft pin.

  3. Remove the J 22102 .
  4. Rotate the crankshaft until the crankshaft sprocket alignment mark is in the 12 o'clock position.

  5. Object Number: 470814  Size: SH

    Important: 

       • Install the camshaft sprocket with the alignment mark in the 6 o'clock position.
       • The sprocket teeth must mesh with the timing chain in order the prevent damage to the camshaft retainer.
       • Do not use a hammer to install the camshaft sprocket onto the camshaft. To do so may damage the camshaft.

  6. Install the camshaft sprocket and timing chain.

  7. Object Number: 677756  Size: SH
  8. Look to ensure that the crankshaft sprocket is aligned at the 12 o'clock position and the camshaft sprocket is aligned at the 6 o'clock position.
  9. 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.

  10. Install the camshaft sprocket bolts.
  11. Tighten

    1. Tighten the camshaft sprocket bolts a first pass to 30 N·m (22 lb ft).
    2. Tighten the camshaft sprocket bolts a final pass to 30 N·m (22 lb ft).
  12. Install the engine front. Refer to Engine Front Cover Replacement .