GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • EN-47812 Installer Bolt
    • J 8433-1 Two Jaw Puller
    • J 41558 Crankshaft Sprocket Remover
    • J 41816-2 Crankshaft End Protector
    • J 41665 Crankshaft Balancer and Sprocket Installer

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: 1552489  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: 1552490  Size: SH
  5. Remove the bolts (231) and chain dampener (232).

  6. Object Number: 1552486  Size: SH
  7. Use the J 41816-2 (1), the J 41558 (2), and the J 8433 (4) 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 (1) into the keyway until both ends of the key bottom onto the crankshaft.

  4. Object Number: 1552487  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: 1552502  Size: SH
  7. Use the EN-47812 (1), and the J 41665 (2) in order to install the crankshaft sprocket. Install the sprocket onto the crankshaft until fully seated against the crankshaft flange.
  8. Rotate the crankshaft sprocket until the alignment mark is in the 12 o'clock position.
  9. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1552490  Size: SH
  10. Install the chain dampener (232) and bolts (231).
  11. Tighten
    Tighten the chain guide bolts to 25 N·m (18 lb ft).


    Object Number: 1552489  Size: SH

    Important: 

       • Properly locate the camshaft sprocket locating pin with the camshaft sprocket alignment hole.
       • The sprocket teeth and timing chain must mesh.
       • The camshaft and the crankshaft sprocket alignment marks MUST be aligned correctly.
            Locate the camshaft sprocket alignment mark in the 6 o'clock position.

  12. Install the camshaft sprocket (205) and timing chain (208). If necessary, rotate the camshaft or crankshaft sprockets in order the align the timing marks.

  13. Object Number: 1649254  Size: SH
  14. Inspect the sprockets for proper alignment. The mark on the camshaft sprocket (1) should be located in the 6 o'clock position and the mark on the crankshaft sprocket (2) should be located in the 12 o'clock position.
  15. Install the camshaft sprocket bolts.
  16. Tighten
    Tighten the camshaft sprocket bolts to 25 N·m (18 lb ft).

  17. Install the oil pump. Refer to Oil Pump, Screen, and Crankshaft Oil Deflector Replacement .