GM Service Manual Online
For 1990-2009 cars only

    Object Number: 897052  Size: SH

    Important: Adjust the valves only when the cylinder head temperature is less than 38°C (100°F).

  1. Rotate the crankshaft to align the mark (2) on the sprocket (237) with the pointer (1) on the oil pump housing.

  2. Object Number: 897035  Size: SH
  3. Rotate the crankshaft balancer and align the white mark (1) on the balancer with the locating tab (2) on the front cover.

  4. Object Number: 897041  Size: SH
  5. Inspect cylinder number 1 for top dead center (TDC) position. The mark (2) on the front cover should be aligned with the mark (1) on the sprocket.

  6. Object Number: 897124  Size: SH
  7. Identify the adjusting bolt (216) and nut (217) locations.

  8. Object Number: 897277  Size: SH
  9. Select the proper thickness feeler gage.
  10. Specification

        • Intake valve adjustment: 0.2-0.24 mm (0.008-0.009 in)
        • Exhaust valve adjustment: 0.28-0.32 mm (0.011-0.013 in)
  11. Insert a feeler gage (1) between the adjusting screws (216) and the ends of the valve stems for cylinder number 1. Slide the feeler gage back and forth, adjusting the screws, until you feel a slight amount of drag. If you feel too much drag, loosen the locknut and turn the adjusting screw (216) until the drag on the feeler gage is correct.
  12. Tighten the locknut and inspect the clearance again. Repeat the adjustment, if necessary.

  13. Object Number: 897280  Size: SH
  14. Rotate the engine clockwise and position number 4 piston at TDC. Align the mark (2) on the front cover with the TDC mark (1) on the sprocket.
  15. Inspect and adjust cylinder number 4 valve clearance, as required.

  16. Object Number: 897278  Size: SH
  17. Rotate the engine and position number 2 piston at TDC. Align the mark (2) on the front cover with the TDC mark (1) on the sprocket.
  18. Inspect and adjust cylinder number 2 valve clearance, as required.

  19. Object Number: 897281  Size: SH
  20. Rotate the engine and position number 5 piston at TDC. Align the mark (2) on the front cover with the TDC mark (1) on the sprocket.
  21. Inspect and adjust cylinder number 5 valve clearance, as required.

  22. Object Number: 897279  Size: SH
  23. Rotate the engine and position number 3 piston at TDC. Align the mark (2) on the front cover with the TDC mark (1) on the sprocket.
  24. Inspect and adjust cylinder number 3 valve clearance, as required.

  25. Object Number: 897282  Size: SH
  26. Rotate the engine and position number 6 piston at TDC. Align the mark (2) on the front cover with the TDC mark (1) on the sprocket.
  27. Inspect and adjust cylinder number 6 valve clearance, as required.