GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 8433 Two Jaw Puller
    • J 41558 Crankshaft Sprocket Remover
    • J 41665 Crankshaft Balancer and Sprocket Installer
    • J 41816-2 Crankshaft End Protector

Removal Procedure

Notice: Do not turn the crankshaft assembly after the timing chain has been removed in order to prevent damage to the piston assemblies or the valves.


    Object Number: 1402055  Size: SH
  1. Remove the oil pump. Refer to Oil Pump, Screen, and Crankshaft Oil Deflector Replacement .
  2. Remove the camshaft sprocket bolts (206).
  3. Remove the camshaft sprocket (205) and timing chain (208).

  4. Object Number: 1402069  Size: SH
  5. Remove the bolts (231) and chain dampener (232).

  6. Object Number: 63189  Size: SH
  7. Use the J 8433 , J 41816-2 and J 41558 in order to remove the crankshaft sprocket.

  8. Object Number: 156150  Size: SH
  9. Remove the crankshaft sprocket.

  10. Object Number: 156149  Size: SH
  11. Remove the crankshaft sprocket key, if required.
  12. Clean and inspect the timing chain and sprockets. Refer to Camshaft Timing Chain and Sprocket Cleaning and Inspection .

Installation Procedure


    Object Number: 156149  Size: SH
  1. Install the key into the crankshaft keyway, if previously removed.

  2. Object Number: 1272887  Size: SH
  3. Tap the key (122) into the keyway until both ends of the key, bottom onto the crankshaft.

  4. Object Number: 1402075  Size: SH
  5. Install the crankshaft sprocket onto the front of the crankshaft. Align the crankshaft key with the crankshaft sprocket keyway.

  6. Object Number: 63199  Size: SH
  7. Use the J 41665 in order to install the crankshaft sprocket.
  8. Install the sprocket onto the crankshaft until fully seated against the crankshaft flange.

  9. Rotate the crankshaft sprocket until the alignment mark is in the 12 o'clock position.
  10. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1402069  Size: SH
  11. Install the timing chain dampener (232) and bolts (231).
  12. Tighten
    Tighten the timing chain dampener bolts to 25 N·m (18 lb ft).


    Object Number: 1402098  Size: SH
  13. With the chain dampener properly installed, the heads of the bolts (231) should install to flush or below the face of the dampener (232).

  14. Object Number: 1402055  Size: SH

    Important: 

       • Properly locate the camshaft sprocket onto the locating pin of the camshaft.
       • The sprocket teeth and timing chain must mesh.
       • The camshaft and the crankshaft sprocket alignment marks MUST be aligned properly.
            Position the camshaft sprocket alignment mark in the 6 o'clock position.

  15. Install the camshaft sprocket (205) and the timing chain (208). If necessary, rotate the camshaft or crankshaft sprockets in order to align the timing marks.
  16. Install the camshaft sprocket bolts (206).
  17. Tighten
    Tighten the camshaft sprocket bolts to 25 N·m (18 lb ft).


    Object Number: 1402101  Size: SH
  18. Inspect for proper alignment of the camshaft and crankshaft sprocket timing marks (1, 2).
  19. Install the oil pump. Refer to Oil Pump, Screen, and Crankshaft Oil Deflector Replacement .