GM Service Manual Online
For 1990-2009 cars only

Secondary Camshaft Drive Chain Replacement Front

Removal Procedure

Tools Required

    • J 42038 Camshaft Holding Fixture
    • J 42042 Timing Chain/Sprocket Holding Fixture
  1. Partially drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  2. Disconnect the thermostat housing for J 42042 access. Refer to Engine Coolant Thermostat Replacement in Engine Cooling.
  3. Remove the left (front) camshaft cover. Refer to Camshaft Cover Replacement .

  4. Object Number: 539986  Size: SH
  5. Install the J 42038 on to the left (front) camshafts.
  6. Remove the camshaft sprocket bolts.

  7. Object Number: 423243  Size: SH
  8. Install the J 42042 on to the left (front) cylinder head.
  9. Evenly slide the secondary drive chain and camshaft sprockets off the camshafts on to the J 42042 .
  10. Inspect the secondary drive chain tensioner.

Installation Procedure

Tools Required

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

    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 two 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 (front) 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.

    Object Number: 539986  Size: SH
  9. Remove the J 42038 from the left (front) camshafts.
  10. Install the left (front) camshaft cover. Refer to Camshaft Cover Replacement .
  11. Install the thermostat housing. Refer to Engine Coolant Thermostat Replacement in Engine Cooling.
  12. Fill the cooling system with engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.

Secondary Camshaft Drive Chain Replacement Rear

Removal Procedure

Tools Required

    • J 42038 Camshaft Holding Fixture
    • J 42042 Timing Chain/Sprocket Holding Fixture
  1. Remove the right (rear) camshaft cover. Refer to Camshaft Cover Replacement .

  2. Object Number: 423255  Size: SH
  3. Install the J 42038 on to the right (rear) camshafts.
  4. Remove the camshaft position sensor. Refer to Camshaft Position Sensor Replacement in Engine Controls - 3.5L.
  5. Remove the camshaft sprocket bolts.
  6. Install the J 42042 on to the right (rear) cylinder head.
  7. Evenly slide the secondary drive chain and camshaft sprockets off the camshafts on to the J 42042 .
  8. Inspect the secondary drive chain tensioner.

Installation Procedure

Tools Required

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

    Object Number: 483133  Size: SH
  1. Install the secondary timing chain. Align the drive pins as shown.
  2. Align the intake sprocket drive pin (1) with the two darkened links (2).

    Align the exhaust sprocket drive pin (3) between the single darkened link (4).


    Object Number: 483133  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.
  4. Remove the J 42042 from the right (rear) cylinder head.
  5. 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.

  6. Install the intake camshaft sprocket bolt and exhaust camshaft sprocket bolt.
  7. 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.

    Object Number: 423255  Size: SH
  8. Remove the J 42038 from the right (rear) camshafts.
  9. Install the camshaft position sensor. Refer to Camshaft Position Sensor Replacement in Engine Controls - 3.5L.
  10. Install the right (rear) camshaft cover. Refer to Camshaft Cover Replacement .