GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • EN-48245 Camshaft Locking Tool
    • EN-48946 Crankshaft Locking Tool

For equivalent regional tools, refer to Special Tools .


    Object Number: 2027174  Size: SH
  1. Rotate the fuel pump drive sprocket that the marks (1) and (2) align.

  2. Object Number: 2027494  Size: SH
  3. Install the timing belt (1) in the following order:
  4. Note: Examine that the timing belt is tensioned during the installation.

    2.1. Crankshaft sprocket (7)
    2.2. Water pump pulley (6)
    2.3. Fuel pump drive pulley (4)
    2.4. Timing belt idler pulley (3)
    2.5. Camshaft drive sprocket (2)
    2.6. Timing belt tensioner (5)

    Object Number: 2027177  Size: SH
  5. Turn the hex-key (1) tab in a counterclockwise direction to tension the belt. Turn until the point aligns with the notch (2).
  6. Caution: Refer to Fastener Caution in the Preface section.

  7. Aligning with notch (2), tighten the timing belt tensioner bolt (3) to  25 N·m (19 lb ft) .

  8. Object Number: 2027175  Size: SH
  9. Remove the EN-48946 locking tool  (1) and remove the bolts (2). Remove EN-48245 locking tool  (4) from the lower crankcase hole (3). Install the lower crankcase closure bolt (5) and tighten to  30 N·m (23 lb ft) .

  10. Object Number: 2027173  Size: SH
  11. Turn the crankshaft in a clockwise direction 2 cycles and check the positions from the crankshaft.
  12. Note: If the timing marks are not aligned, repeat the forward procedure and recheck the marks. Alignment of marks is critical for engine performance and emissions.


    Object Number: 2027172  Size: SH
  13. Check the camshaft position.
  14. Note: 

       • Examine that the bore (1) in the camshaft (2) is on top.
       • Examine the correct positions of the camshaft and the crankshaft.


    Object Number: 2027460  Size: SH
  15. Install a NEW vacuum pump gasket (3).
  16. Note: Ensure that the vacuum pump surface and cylinder head surface are clear of old gasket material.

  17. Install the vacuum pump (1).
  18. Caution: Refer to Fastener Caution in the Preface section.

  19. Install the 4 vacuum pump bolts (2) and tighten to  12 N·m (107 lb in) .

  20. Object Number: 2027459  Size: SH
  21. Install the wiring harness bracket (1).
  22. Install the 2  wiring harness bracket nuts (2) and tighten to  20 N·m (15 lb ft) .

  23. Object Number: 2027461  Size: SH
  24. Install 4 wiring harness clips (1) to the bracket (3).
  25. Install the wiring harness plug (2).