GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 36660-A Electronic Torque Angle Meter
    • J 42038 Camshaft Holding Fixture
    • J 42042 Timing Chain/Sprocket Holding Fixture

Removal Procedure

  1. Remove the thermostat housing for J 42042 access. Refer to Engine Coolant Thermostat Replacement in Engine Cooling.
  2. Remove the left camshaft cover. Refer to Camshaft Cover Replacement - Left Side .

  3. Object Number: 539986  Size: SH
  4. Install the J 42038 on to the left camshafts.

  5. Object Number: 482996  Size: SH
  6. Compress the left secondary drive chain tensioner with your hand.
  7. Lock the left secondary drive chain tensioner by inserting a piece of wire (2) into the access hole in the side of the tensioner.
  8. Slowly release the pressure from the left secondary drive chain tensioner shoes. The tensioner should remain compressed.
  9. Remove the camshaft sprocket bolts.

  10. Object Number: 423243  Size: SH
  11. Install the J 42042 on to the left cylinder head.
  12. Evenly slide the secondary drive chain and camshaft sprockets off the camshafts on to the J 42042 .
  13. Remove the secondary camshaft drive chain from the camshaft sprockets.
  14. Inspect the secondary drive chain tensioner.

Installation Procedure


    Object Number: 287924  Size: SH
  1. Install the secondary timing chain. Align the drive pins as shown.
  2. • Align the exhaust sprocket drive pin (1) between the 2 darkened links (2).
    • Align the intake sprocket drive pin (4) with the single darkened link (3).

    Object Number: 287924  Size: SH
  3. Slide the intake and exhaust camshaft sprockets off of the J 42042 and onto their respective camshafts and align the drive pins (1, 4) in the camshafts. Make sure the chain is properly aligned on the drive chain tensioner.

  4. Object Number: 423243  Size: SH
  5. Remove the J 42042 from the left cylinder head.
  6. 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.

  7. Install the intake camshaft sprocket bolt and exhaust camshaft sprocket bolt.
  8. Tighten

    1. Tighten the camshaft sprocket bolts to 25 N·m (18 lb ft).
    2. Use the J 36660-A in order to tighten the camshaft sprocket bolts an additional 45 degrees.
  9. Remove the locking wire from the left secondary drive chain tensioner allowing the tensioner shoes to expand and apply pressure to the drive chain.

  10. Object Number: 539986  Size: SH
  11. Remove the J 42038 from the left camshafts.
  12. Install the left camshaft cover. Refer to Camshaft Cover Replacement - Left Side .
  13. Install the thermostat housing. Refer to Engine Coolant Thermostat Replacement in Engine Cooling.