GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • J 36660-A Torque Angle Meter
    • J 44221 Camshaft Holding Tool

Removal Procedure


    Object Number: 760721  Size: SH
  1. Remove the camshaft cover. Refer to Camshaft Cover Replacement .
  2. Remove the engine front cover. Refer to Engine Front Cover Replacement .
  3. Release the tension on the timing chain by moving the tensioner shoe in.

  4. Object Number: 760718  Size: SH
  5. Place the tee into the tensioner to hold the shoe in place.

  6. Object Number: 1530236  Size: SH
  7. Remove the exhaust camshaft position actuator bolt.
  8. Remove the exhaust camshaft position actuator.

  9. Object Number: 637575  Size: SH
  10. Remove the intake camshaft sprocket bolt.
  11. Remove the intake camshaft sprocket.
  12. Remove the timing chain.
  13. Remove the crankshaft sprocket.

  14. Object Number: 637770  Size: SH
  15. Remove the cylinder head access hole plugs.

  16. Object Number: 637584  Size: SH
  17. Remove the timing chain tensioner shoe bolt.
  18. Remove the timing chain tensioner shoe.

  19. Object Number: 637585  Size: SH
  20. Remove the timing chain tensioner guide bolts.
  21. Remove the timing chain tensioner guide.

  22. Object Number: 637580  Size: SH
  23. Remove the timing chain tensioner bolts.
  24. Remove the timing chain tensioner.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 637580  Size: SH

    Important: Every seventh link of the timing chain is darkened to aid in aligning the timing marks.

  1. Install the timing chain tensioner and secure the tensioner with the bolts.
  2. Tighten
    Tighten the timing chain tensioner bolts to 25 N·m (18 lb ft).


    Object Number: 637585  Size: SH
  3. Install the timing chain tensioner guide and secure the guide with the bolts.
  4. Tighten
    Tighten the timing chain tensioner guide to 10 N·m (89 lb in).


    Object Number: 637584  Size: SH
  5. Install the timing chain tensioner shoe and secure the shoe with the bolt.
  6. Tighten
    Tighten the timing chain tensioner shoe bolt to 26 N·m (19 lb ft).


    Object Number: 637770  Size: SH
  7. Install the cylinder head access hole plugs.
  8. Tighten
    Tighten the cylinder head access hole plugs to 5 N·m (44 lb in).


    Object Number: 748322  Size: SH
  9. Install the J 44221 with the camshaft flats up and the number 1 piston at top dead center. The crank pin will be at 12 o'clock when the number 1 piston is at top dead center.

  10. Object Number: 637578  Size: SH
  11. Install the crankshaft sprocket (1).
  12. Install the intake camshaft sprocket into the timing chain. Refer to Camshaft Position Actuator Diagnosis .
  13. Align the dark link of the timing chain with the timing mark on the intake camshaft sprocket (1).
  14. Feed the timing chain down through the opening in the head.
  15. Install the timing chain on the crankshaft sprocket. Align the dark link of the timing chain with the timing mark on to the crankshaft sprocket.
  16. Important: It may be necessary to remove J 44221 to rotate and hold the camshaft (hex) to align the pin to the camshaft sprocket.

  17. Install the intake camshaft sprocket onto the intake camshaft.
  18. Install the intake camshaft sprocket washer and bolt.

  19. Object Number: 1530242  Size: SH
  20. Install the exhaust camshaft actuator into the timing chain.
  21. Align the dark link of the timing chain with the timing mark on the exhaust camshaft actuator (1).
  22. Important: It may be necessary to remove the J 44221 to rotate and hold the camshaft hex to align the pin to the camshaft sprocket.

  23. Install the exhaust camshaft actuator onto the exhaust camshaft.

  24. Object Number: 1530236  Size: SH
  25. Install the exhaust camshaft actuator bolt.
  26. Tighten

        • Tighten the exhaust camshaft actuator bolt the first pass to 25 N·m (18 lb ft).
        • Use J 36660-A to tighten the exhaust camshaft actuator bolt the final pass an additional 135 degrees.
  27. Install the intake camshaft sprocket bolt.
  28. Tighten

        • Tighten the intake camshaft sprocket bolt the first pass to 20 N·m (15 ft lb).
        • Use J 36660-A to tighten the intake camshaft sprocket bolt the final pass an additional 100 degrees.

    Object Number: 760718  Size: SH
  29. Remove the tee in the timing chain tensioner to regain tension on the timing chain.
  30. Remove the J 44221 .

  31. Object Number: 1530243  Size: SH
  32. The dark lines (1) on the chain should be aligned with the marks on the sprockets as shown.
  33. Install the engine front cover. Refer to Engine Front Cover Replacement .
  34. Install the camshaft cover. Refer to Camshaft Cover Replacement .