GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 45059 Angle Meter
    • KM-470-B Angular Torque Gage

Removal Procedure


    Object Number: 1252112  Size: SH
  1. Remove the timing belt. Refer to Timing Belt Replacement .
  2. Disconnect the breather tube at the valve cover.
  3. Disconnect the crankcase ventilation tube at the valve cover.
  4. Remove the spark plug cover bolts.
  5. Remove the spark plug cover.
  6. Disconnect the ignition wires from the spark plugs.
  7. Remove the valve cover bolts.
  8. Remove the valve cover washers.
  9. Remove the valve cover and the valve cover gasket.

  10. Object Number: 1252121  Size: SH

    Notice: Use extreme care when installing the camshaft not to nick, scratch, or damage the camshaft lobes or bearing surfaces.

  11. While holding the intake camshaft firmly in place, remove the intake camshaft gear bolt.
  12. Remove the intake camshaft gear.
  13. While holding the exhaust camshaft firmly in place, remove the exhaust camshaft gear bolt.
  14. Remove the exhaust camshaft gear.

  15. Object Number: 1289786  Size: SH
  16. Loosen the camshaft bearing cap bolts in stages of one-half to one turn.
  17. Remove the camshaft bearing cap bolts from the cylinder head.
  18. Remove the camshafts.
  19. Remove the seal ring from the camshafts.
  20. Important: The camshaft must detach evenly from the bearing seals in the front guide bearing.

  21. Check the camshaft and bearing seats for wear and replace them if necessary.

Installation Procedure

    Notice: Use extreme care when installing the camshaft not to nick, scratch, or damage the camshaft lobes or bearing surfaces.


    Object Number: 1252134  Size: SH
  1. Lubricate the camshaft journals and the camshaft caps with engine oil.
  2. Install the intake camshaft.
  3. Install the intake camshaft caps in their original positions.
  4. Install the intake camshaft cap bolts.
  5. Install the exhaust camshaft.
  6. Install the exhaust camshaft caps in their original positions.
  7. Install the exhaust camshaft cap bolts.
  8. Notice: Refer to Fastener Notice in the Preface section.

  9. Tighten the camshaft cap bolts gradually and in the sequence shown for each camshaft cap.
  10. Tighten
    Tighten the camshaft bearing cap bolts to 8 N·m (71 lb in).


    Object Number: 1252130  Size: SH
  11. Measure the intake camshaft end play and the exhaust camshaft end play. Refer to Engine Mechanical Specifications .
  12. Install the intake camshaft gear.
  13. While holding the intake camshaft firmly in place, install the intake camshaft gear bolt.
  14. Tighten
    Tighten the intake camshaft gear bolt to 50 N·m (37 lb ft). Turn the bolt another 60 degrees and 15 degrees using the J 45059 or the KM-470-B .


    Object Number: 1252121  Size: SH
  15. Install the exhaust camshaft gear.
  16. Notice: Refer to Camshaft Journal Diameter Notice in the Preface section.

  17. While holding the exhaust camshaft firmly in place, install the exhaust camshaft gear bolt.
  18. Tighten
    Tighten the exhaust camshaft gear bolt to 50 N·m (37 lb ft), turn the bolt another 60 degrees and 15 degrees using the J 45059 or the KM-470-B .


    Object Number: 1252112  Size: SH
  19. Install the valve cover and the valve cover gasket.
  20. Install the valve cover washers.
  21. Install the valve cover bolts.
  22. Tighten
    Tighten the valve cover bolts to 8 N·m (71 lb in).


    Object Number: 1289763  Size: SH
  23. Connect the ignition wires to the spark plugs.
  24. Install the spark plug cover.
  25. Install the spark plug cover bolts.
  26. Tighten
    Tighten the spark plug cover bolts to 8 N·m (71 lb in).

  27. Connect the crankcase velitation tube to the valve cover.
  28. Connect the breather tube to the valve cover.
  29. Install the timing belt. Refer to Timing Belt Replacement .