GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 43032 Crankshaft Socket


    Object Number: 263906  Size: SH
  1. Place the primary camshaft drive chain tensioner oil tube (1) in position on the cylinder block.
  2. 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.

  3. Install the primary camshaft drive chain tensioner oil tube bolts.
  4. Tighten
    Tighten the primary camshaft drive chain tensioner oil tube bolts to 9 N·m (80 lb in).


    Object Number: 235173  Size: SH
  5. Install the primary camshaft drive chain.

  6. Object Number: 287919  Size: SH

    Important:  Do not remove the J 42038 .

  7. To assist in primary camshaft drive chain installation, use an open end wrench on the hex cast into the camshaft to provide minor adjustments to the secondary sprocket position.

  8. Object Number: 263904  Size: SH
  9. When installing the primary camshaft drive chain you must set the base engine timing. Base engine timing is set with cylinder number one at top dead center (TDC) starting the intake stroke and with the correct camshaft to balance shaft to crankshaft relationship. To set the correct base engine timing proceed as follows:
  10. 5.1. Rotate the crankshaft until cylinder number one is at top dead center and the crankshaft sprocket timing mark (6) is at the four o'clock position using the J 43032 .
    5.2. Rotate the balance shaft until its timing mark (7) is at the five o'clock position.
  11. Make sure the darkened chain links on the primary camshaft drive chain are facing toward the front of the engine.
  12. Center the timing mark (1) on the left hand intake camshaft between the paired darkened timing links (2) and wrap the chain around the sprocket. Allow the remainder of the primary camshaft drive chain to drop into the crankcase area once the timing mark is aligned.
  13. Fabricate a hook out of wire and feed it down through the right cylinder head. Use the hook to pull the remainder of the primary camshaft drive chain up to the right intake camshaft sprocket.
  14. While pulling the timing chain up to the right cylinder head, align the darkened chain links with the balance shaft (7) and crankshaft (6) sprockets.
  15. Wrap the primary camshaft drive chain around the right intake camshaft sprocket and align the darkened link (8) with the sprocket's timing mark (9).
  16. Make sure all the timing marks are properly aligned with the darkened chain links.

  17. Object Number: 235189  Size: SH
  18. Install the primary camshaft drive chain tensioner shoe (1).
  19. Install the primary camshaft drive chain tensioner shoe bolt using the access hole in the cylinder head.
  20. Tighten
    Tighten the primary camshaft drive chain tensioner shoe bolt to 30 N·m (22 lb ft).


    Object Number: 240843  Size: SH
  21. Collapse the primary camshaft drive chain tensioner using the following procedure:
  22. 14.1. Rotate the ratchet release lever (2) counterclockwise and hold.
    14.2. Collapse the tensioner shoe (1) and hold.
    14.3. Release the ratchet lever and slowly release the pressure on the shoe.
  23. As the ratchet lever moves to its first click, hold the tensioner shoe inward. Insert a pin through the hole in the release lever.
  24. The locked ratchet mechanism should hold the shoe in a collapsed position.

  25. Object Number: 235192  Size: SH

    Important: Ensure that the primary camshaft drive chain tensioner release lever faces toward you before tightening.

  26. Install the primary camshaft drive chain tensioner (1) and primary camshaft drive chain tensioner bolts.
  27. Tighten
    Tighten the primary camshaft drive chain tensioner bolts to 25 N·m (18 lb ft).


    Object Number: 263904  Size: SH
  28. Ensure that all the timing marks (1-9) are properly aligned. Make adjustments as necessary.
  29. Remove the pin holding the primary camshaft drive chain tensioner to tighten any slack in the timing chain.

  30. Object Number: 233789  Size: SH

    Important: Ensure that each chain guide access plug has an O-ring installed.

  31. Install the four chain guide access plugs.
  32. Tighten
    Tighten the chain guide access plugs to 5 N·m (44 lb in).


    Object Number: 235239  Size: SH
  33. Install a NEW O-ring on the camshaft position sensor.
  34. Lubricate the O-ring with clean engine oil.
  35. Install the camshaft position sensor.
  36. Install the camshaft position sensor and bolt.
  37. Tighten
    Tighten the camshaft position sensor bolt to 9 N·m (80 lb in).


    Object Number: 233793  Size: SH
  38. Install the front engine lift bracket, hex head bolt and TORX® internal drive bolt.
  39. Tighten

    1. Tighten the front lift bracket hex head bolt to 50 N·m (37 lb ft).
    2. Tighten the front lift bracket TORX® internal drive bolt to 25 N·m (18 lb ft).