GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • EN 46330 Timing Chain Tensioner Retaining Pin
    • J 8433 Puller Bar
    • J 41478 Crankshaft Front Oil Seal Installer
    • J 41558 Crankshaft Sprocket Remover
    • J 41665 Crankshaft Balancer and Sprocket Installer
    • J 41816-2 Crankshaft End Protector
    • J 42386-A Flywheel Holding Tool
    • J 45059 Angle Meter

Removal Procedure


    Object Number: 1658136  Size: SH
  1. Remove the oil pump. Refer to Oil Pump, Screen, and Crankshaft Oil Deflector Replacement.
  2. Remove the starter motor. Refer to Starter Motor Replacement.
  3. Notice: Refer to Fastener Notice in the Preface section.

    Important: Ensure that the teeth of the J 42386-A mesh with the teeth of the engine flywheel.

  4. Install the J 42386-A  (1) and bolts. Use one M10-1.5 x 120 mm and one M10-1.5 x 45 mm bolt for proper tool operation.
  5. Tighten
    Tighten the J 42386-A bolts to 50 N·m (37 lb ft).


    Object Number: 1670623  Size: SH
  6. Rotate the crankshaft sprocket until the camshaft position (CMP) actuator alignment mark (1) and the crankshaft sprocket alignment mark (2) are aligned.

  7. Object Number: 1670622  Size: SH
  8. Remove and discard the CMP actuator solenoid valve (234).

  9. Object Number: 1658255  Size: SH

    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.

  10. Remove the CMP actuator (235) and timing chain (208).

  11. Object Number: 1714936  Size: MH

    Caution: Do not push or pull on the reluctor wheel of the camshaft position (CMP) actuator during removal or installation. The reluctor wheel is retained to the front of the CMP actuator by 3 roll pins. Pushing or pulling on the wheel may dislodge the wheel from the front of the actuator. The actuator return spring is under tension and may rotate the dislodged reluctor wheel, causing personal injury.

  12. Loosen and separate the CMP actuator and timing chain from the camshaft. Position your fingers behind the actuator sprocket and pull the actuator away from the front of the camshaft. Never pull on the reluctor wheel when attempting to remove the actuator.

  13. Object Number: 1714946  Size: SH
  14. Insert and secure a tie strap (1) through the center of the actuator and over the reluctor wheel.

  15. Object Number: 1658178  Size: SH
  16. Remove the timing chain tension bolts (231) and tensioner (232).

  17. Object Number: 1658180  Size: SH
  18. Using the J 41816-2  (1), the J 41558  (2), bolts (3) and the J 8433  (4) in order to remove the crankshaft sprocket.

  19. Object Number: 1658182  Size: SH
  20. Remove the crankshaft sprocket (207).

  21. Object Number: 156149  Size: SH
  22. Remove the crankshaft sprocket key, if required.

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: 1658182  Size: SH
  5. Install the crankshaft sprocket (207) onto the front of the crankshaft. Align the crankshaft key with the crankshaft sprocket keyway.

  6. Object Number: 1658237  Size: SH
  7. Use the J 41478  (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. Object Number: 1658249  Size: SH
  9. Compress the timing chain tensioner guide and install the EN 46330 .

  10. Object Number: 1658251  Size: SH
  11. Install the timing chain tensioner (232) and bolts (231).
  12. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).


    Object Number: 1658240  Size: SH

    Important: 

       • Properly locate the CMP actuator onto the locating pin of the camshaft.
       • The sprocket teeth and timing chain teeth must mesh.
       • The camshaft and the crankshaft sprocket alignment MUST be aligned properly.
       • Do not use the CMP solenoid valve again. Install a NEW CMP valve during assembly.

  13. Identify the alignment hole (1) in the rear face of the CMP actuator and the locating pin (2) on the front face of he camshaft.

  14. Object Number: 1670621  Size: SH
  15. Align the CMP actuator so the timing mark is in the 6 o'clock position.
  16. Install the CMP actuator (235) and timing chain (208). Align the hole in the face of the CMP actuator with the locating pin on the front face of the camshaft.

  17. Object Number: 1714942  Size: MH

    Caution: Do not push or pull on the reluctor wheel of the camshaft position (CMP) actuator during removal or installation. The reluctor wheel is retained to the front of the CMP actuator by 3 roll pins. Pushing or pulling on the wheel may dislodge the wheel from the front of the actuator. The actuator return spring is under tension and may rotate the dislodged reluctor wheel, causing personal injury.

  18. Use care to install the actuator completely onto the front of the camshaft. Position your fingers onto the face of the actuator sprocket and push the actuator onto the front of the camshaft. Never push on the reluctor wheel when attempting to install the actuator.

  19. Object Number: 1670626  Size: SH
  20. Place a straight edge across the front face of the engine block and inspect for proper installation of the CMP actuator and timing chain. With the CMP actuator properly and completely installed onto the front of the camshaft, the timing chain will not protrude beyond the front face of the engine block.

  21. Object Number: 1670622  Size: SH
  22. Install a NEW CMP actuator valve (234). With the CMP actuator properly positioned onto the camshaft, the CMP actuator solenoid valve can be threaded completely into the camshaft using light hand pressure. Tighten by hand until snug.

  23. Object Number: 1670623  Size: SH
  24. Inspect the sprockets for proper alignment. The mark on the CMP (1) actuator sprocket 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.

  25. Object Number: 1658253  Size: SH
  26. Remove the EN 46330 .

  27. Object Number: 1658245  Size: SH
  28. Tighten the CMP actuator solenoid valve.
  29. Tighten

    1. Tighten the bolt a first pass to 65 N·m (48 lb ft).
    2. Tighten the bolt a final pass an additional 90 degrees using J 45059 .

    Object Number: 1658136  Size: SH
  30. Remove the J 42386-A  (1) and bolts.
  31. Install the starter motor. Refer to Starter Motor Replacement.
  32. Install the oil pump. Refer to Oil Pump, Screen, and Crankshaft Oil Deflector Replacement.