GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • J 44221 Camshaft Holding Tool
    • J 44222 Camshaft Sprocket Holding Tool
    • J 45059 Angle Meter

Removal Procedure

  1. Remove the camshaft cover. Refer to Camshaft Cover Replacement.
  2. Remove the exhaust camshaft position (CMP) sensor. Refer to Camshaft Position Sensor Replacement - Exhaust.
  3. Remove the intake CMP sensor. Refer to Camshaft Position Sensor Replacement - Intake.
  4. Rotate the crankshaft in the engine rotational direction clockwise, until the number 1 piston is at top dead center (TDC) on the compression stroke.
  5. Warning: Refer to Camshaft Holding Tool Warning in the Preface section.


    Object Number: 858336  Size: SH
  6. Install the J 44221 to the rear of the camshafts.
  7. Remove and discard the intake and the exhaust camshaft sprocket bolts.

  8. Object Number: 760724  Size: SH
  9. Install the J 44222 onto the cylinder head and adjust the horizontal bolts into the camshaft sprockets in order to maintain chain tension and keep from disturbing the timing chain components.
  10. Carefully slide the sprockets with the timing chain from the camshafts to the J 44222 .

  11. Object Number: 858183  Size: SH
  12. Alternately loosen the camshaft cap bolts a few turns at a time until all valve spring pressure has been released.
  13. Note: Place the camshaft caps in a rack to ensure the caps are installed in the same location from which they were removed.

  14. Remove the camshaft caps.
  15. Remove the J 44221 from the camshafts.

  16. Object Number: 858184  Size: SH
  17. Remove the camshafts from the cylinder head.
  18. Clean and inspect the camshafts. Refer to Camshafts Cleaning and Inspection.

Installation Procedure

  1. Coat the camshaft journals, camshaft journal thrust face, and camshaft lobes with clean engine oil.

  2. Object Number: 858334  Size: SH
  3. Install the J 44221 with the camshaft flats up and the number 1 piston at TDC.
  4. Install the intake and exhaust camshafts to their original positions.

  5. Object Number: 53008  Size: SH
  6. Observe the markings on the camshaft caps. Each camshaft cap is marked in order to identify its location. The markings have the following meanings:
  7. • The arrow should point to the front of the engine
    • The number indicates the position from the front of the engine
    • The "E" indicates the exhaust camshaft.
    • The "I" indicates the intake camshaft.

    Object Number: 858183  Size: SH
  8. Install the camshaft caps according to the identification marks.
  9. Caution: Refer to Fastener Caution in the Preface section.

  10. Install the camshaft cap bolts and tighten to 12 N·m (106 lb in). Tighten the bolts evenly in order to compress the valve springs before final torque.

  11. Object Number: 760724  Size: SH

    Note: 

       • To aid in aligning the sprockets to the camshafts, use a 25 mm (1 in) wrench on the hex of the camshafts to rotate
       • Ensure the alignment pins are properly engaged with the camshafts

  12. Carefully slide the sprockets with the timing chain from the J 44222 to the camshafts.
  13. Remove the J 44222 from the cylinder head.
  14. Install the new intake camshaft sprocket bolt.
  15. Install the new exhaust camshaft actuator bolt.
  16. • Tighten the intake camshaft sprocket bolt a first pass to 20 N·m (15 lb ft). Using the J 45059 rotate the bolt a final pass an additional 100 degrees.
    • Tighten the exhaust camshaft sprocket bolt a first pass to 25 N·m (18 lb ft). Using the J 45059 rotate the bolt a final pass an additional 135 degrees.

    Object Number: 858336  Size: SH
  17. Remove the J 44221 from the camshafts.
  18. Install the intake CMP sensor. Refer to Camshaft Position Sensor Replacement - Intake.
  19. Install the exhaust CMP sensor. Refer to Camshaft Position Sensor Replacement - Exhaust.
  20. Install the camshaft cover. Refer to Camshaft Cover Replacement.