GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 42069 Timing Belt Alignment Kit
    • J 42098 Crank Hub TORX Socket

Installation and Initial Adjustment Procedure

Notice: When installing a new or used timing belt, the directional arrows on the timing belt must be matched with the rotation of the crankshaft. If this precaution is not observed, excessive wear and timing belt failure may occur.

Important: Guide marks are printed on the timing belt to aid in installation. If these marks are not identifiable, install a new belt.

Arrows are printed on the timing belt indicating the required direction of travel. When installing the timing belt, ensure the arrows are traveling in engine rotational direction (clockwise).

Install the timing belt with the engine at room temperature.

Do not crimp or bind the timing belt when handling or installing.


    Object Number: 345370  Size: SH
  1. Start at the crankshaft drive gear and install the timing belt with the double dash (TDC) mark on the belt aligned with the marks on the oil pump and on the belt drive gear.
  2. Use the J 42069-30 to pinch the belt to prevent the teeth from jumping.

  3. Object Number: 345867  Size: SH
  4. Route the timing belt through the timing belt tensioner (2).
  5. Slip the timing belt through camshaft gears 1 and 2 simultaneously (3), ensuring the dash marks on the timing belt align with the marks on the camshaft gears and the notches on the rear timing belt cover.
  6. Route the timing belt through the idler pulley for camshafts 1 and 2 (4).
  7. Route the timing belt through the idler pulley for camshafts 3 and 4 (5).
  8. Slip the timing belt through camshaft gears 3 and 4 simultaneously (6), ensuring the dash marks on the timing belt align with the marks on the camshaft gears and the notches on the rear timing belt cover.

  9. Object Number: 345373  Size: MH
  10. Measure the timing belt deflection between camshaft gear number 4 and the idler pulley for camshafts 3 and 4, the deflection must be no more than 1 cm (0.4 in).

  11. Object Number: 345386  Size: MH
  12. If timing belt deflection adjustment is necessary:
  13. 9.1. Turn the timing belt idler pulley eccentric for camshafts 3 and 4 COUNTERCLOCKWISE, with J 42069-40, until the high point of the eccentric is in approximately the 12 o'clock position.
    9.2. Tighten the idler pulley locking bolt, while holding the eccentric with J 42069-40, until snug. The idler pulley bolt will be tightened to specifications after all final adjustments are made.
  14. Apply additional tension to the timing belt, at the idler pulley for camshafts 1 and 2, by turning the high point of the eccentric to approximately the 9 o'clock position. Then, tighten the idler pulley locking bolt, while holding the eccentric with J 42069-40, until snug.
  15. The idler pulley bolt will be tightened to specifications after all final adjustments are made.


    Object Number: 345812  Size: MH
  16. Set the INITIAL timing belt tension:
  17. 11.1. Turn the tensioner eccentric COUNTERCLOCKWISE to full stop, then, turn the eccentric back until the reference mark is 1 mm (0.003 in) over the flange.
    11.2. Tighten the timing belt tensioner locking nut until snug, the locking nut will be tightened to specifications after all final adjustments are made.
  18. Inspect the alignment marks on the timing belt to ensure that they are aligned with the appropriate reference points on the camshaft gears, the rear timing belt cover and on the oil pump housing.

  19. Object Number: 345367  Size: SH
  20. Remove the J 42069-30, the J 42069-1 and the J 42069-2 locking tools from the engine.
  21. Rotate the crankshaft, with J 42069 , in the clockwise direction two revolutions stopping at 60 degrees BTDC.

  22. Object Number: 345377  Size: SH
  23. Install the J 42069-10 crankshaft locking tool to the crankshaft drive gear with the knurled bolt.
  24. Turn the crankshaft until the lever of the J 42069-10 Crankshaft Locking Tool firmly contacts the water pump pulley flange.
  25. Secure the moveable lever of the tool to the water pump pulley flange.
  26. Important: The alignment marks on the timing belt will no longer align with the marks on the camshaft gears after one or more engine revolutions.

  27. Inspect the alignment of the reference marks on the camshaft gears with the notches on the rear timing belt cover, as well as, the mark on the crankshaft drive gear and oil pump housing.
  28. Use the J 42069-20 checking gauge to inspect the alignment of camshaft gears 3 & 4.
  29. Use the J 42069-20 checking gauge to inspect the alignment of camshaft gears 1 & 2.
  30. Important: The reference marks on both sets of the camshaft gears must match exactly with the marks on the J 42069-20 checking gauge.

    If timing belt adjustment is necessary, always set the adjustment for camshafts 3 and 4 first.

  31. If timing belt adjustment IS REQUIRED, continue further on to the Timing Belt Timing Procedure.

  32. Object Number: 345835  Size: MH
  33. If timing belt adjustment IS NOT REQUIRED, set the final timing belt tension:
  34. 22.1. Loosen the timing belt tensioner eccentric locking nut.
    22.2. Turn the eccentric counterclockwise to full stop, then back until the reference mark is 2-4 mm (0.078-0.157 in) ABOVE the reference mark on the flange.

    Tighten
    Tighten the timing belt tensioner eccentric locking nut 20 N·m (15 lb ft).

    22.3. Hold the timing belt idler pulley eccentrics in place for camshafts 1 & 2 and 3 & 4 with the J 42069-40 adjustment wrench.

    Tighten
    Tighten both idler pulley bolts to 40 N·m (30 lb ft).


    Object Number: 345386  Size: MH
  35. Inspect the high-points of the timing belt tensioner eccentrics. The idler pulley eccentric high point for camshafts 3 and 4 will be in approximately the 12 o'clock position. The idler pulley eccentric high point for camshafts 1 and 2 will be in approximately the 9 o'clock position.
  36. Remove the J 42069-20 checking gauge and the J 42069-10 crankshaft locking tool.
  37. For final inspection, rotate the engine in the clockwise direction two revolutions until reaching 60 degrees BTDC.

  38. Object Number: 345377  Size: SH
  39. Install the J 42069-10 crankshaft locking tool to the crankshaft drive gear with the knurled bolt.
  40. Turn the crankshaft until the lever of the J 42069-10 Crankshaft Locking Tool firmly contacts the water pump pulley flange.
  41. Secure the moveable lever of the tool to the water pump pulley flange.
  42. Inspect the alignment of the reference marks on the camshaft gears with the notches on the rear timing belt cover, as well as, the mark on the crankshaft gear and the mark on the oil pump housing.
  43. Use the J 42069-20 checking gauge to inspect the alignment of camshaft gears 3 and 4.
  44. Use the J 42069-20 checking gauge to inspect the alignment of camshaft gears 1 and 2.
  45. If the reference marks on the camshaft gears do not match exactly, timing belt adjustment IS REQUIRED.
  46. Continue further on to the Timing Belt Timing Procedure.

  47. If the reference marks match exactly and further timing belt adjustment IS NOT necessary.
  48. Continue with reassembly of the engine.

  49. Ensure all of the tools are removed from the engine.

Timing Belt Timing Procedure

Important: The following steps are the continuation of installing the timing belt and must not be performed as a stand-alone operation.

It is not uncommon to repeat steps and make several engine revolutions to achieve the proper level of timing belt adjustment.

Important: Whenever timing belt adjustment is necessary, always start with, and adjust, camshafts 3 and 4 first.

  1. Apply the J 42069-20 checking gauge to camshaft gears 3 and 4.
  2. Inspect the relationship of the marks on the camshaft gears to the marks on the J 42069-20 checking gauge. They must match exactly, if not, timing belt adjustment is required.
  3. Apply the J 42069-20 checking gauge to camshaft gears 1 and 2.
  4. Inspect the relationship of the marks on the camshaft gears to the marks on the J 42069-20 checking gauge. They must match exactly, if not, timing belt adjustment is required.
  5. Continue to the next applicable procedure:

Marks on Camshaft Gears 3 and 4 Align to the LEFT of J 42069-20

  1. Loosen the timing belt idler pulley for camshaft gears 3 & 4.

  2. Object Number: 345814  Size: MH
  3. Use the J 42069-40 adjustment wrench to turn the eccentric on the idler pulley COUNTERCLOCKWISE until the marks on the camshaft gears and on the J 42069-20 Checking Gauge are in alignment (the high point of the idler pulley eccentric will be in approximately the 12 o'clock position).
  4. Tighten
    Tighten the timing belt idler pulley bolt, while holding the eccentric in place with the J 42069-40 adjustment wrench to prevent movement, to 40 N·m (30 lb ft).

  5. Remove the J 42069-10 crankshaft locking tool and the J 42069-20 checking gauge.
  6. Turn the crankshaft in the engine rotational direction two revolutions with the J 42069 . Stop at 60 degrees BTDC.
  7. Install the J 42069-10 crankshaft locking tool to the crankshaft drive gear with the knurled bolt.
  8. Use the J 42069 to carefully turn the crankshaft until the lever of the J 42069-10 firmly contacts the water pump pulley flange.
  9. Secure the moveable lever of the tool to the water pump pulley flange.
  10. Install the J 42069-20 checking gauge to camshaft gears 3 & 4.
  11. Inspect the alignment of the marks on the camshaft gears in reference to the marks on the J 42069-20 checking gauge.
  12. Repeat the procedure again if the marks do not align.
  13. If camshaft gears 3 and 4 are properly aligned, continue checking the timing belt adjustment of camshaft gears 1 & 2. Make necessary corrections as outlined further on in this section.
  14. AFTER all applicable camshaft gear adjustments are made, set the final timing belt tensioner as outlined in Timing Belt Tensioner Adjustment at the end of this procedure.

Marks on Camshaft Gears 3 and 4 Align to the RIGHT of J 42069-20

  1. Loosen the timing belt idler pulley for camshaft gears 3 & 4.

  2. Object Number: 345821  Size: MH
  3. Slacken the timing belt by turning the eccentric on the idler pulley CLOCKWISE with the J 42069-40 adjustment wrench until the marks on the camshaft gears and the marks on the J 42069-20 checking gauge are in alignment (the high point of the idler pulley eccentric will be in approximately the 12 o'clock position).
  4. Tighten
    Tighten the timing belt idler pulley bolt, while holding the eccentric in place with the J 42069-40 adjustment wrench to prevent movement, to 40 N·m (30 lb ft).

  5. Remove the J 42069-10 crankshaft locking tool and the J 42069-20 checking gauge.
  6. Turn the crankshaft in the engine rotational direction two revolutions with the J 42069 . Stop at 60 degrees BTDC.
  7. Install the J 42069-10 crankshaft locking tool to the crankshaft drive gear with the knurled bolt.
  8. Use the J 42069 to carefully turn the crankshaft until the lever of the J 42069-10 firmly contacts the water pump pulley flange.
  9. Secure the moveable lever of the tool to the water pump pulley flange.
  10. Install the J 42069-20 checking gauge to camshaft gears 3 & 4.
  11. Inspect the alignment of the marks on the camshaft gears in reference to the marks on the J 42069-20 checking gauge.
  12. Repeat the procedure again if the marks do not align.
  13. If camshaft gears 3 and 4 are properly aligned, continue checking the timing belt adjustment of camshaft gears 1 and 2. Make necessary corrections as outlined further on in this section.
  14. AFTER all applicable camshaft gear adjustments are made, set the final timing belt tensioner as outlined in Timing Belt Tensioner Adjustment at the end of this procedure.

Marks on Camshaft Gears 1 and 2 Align to the LEFT of J 42069-20

  1. Loosen the timing belt idler pulley for camshaft gears 1 & 2.

  2. Object Number: 345823  Size: MH
  3. Use the J 42069-40 adjustment wrench to turn eccentric on the idler pulley COUNTERCLOCKWISE until the marks on the camshaft gears and on the J 42069-20 checking gauge are in alignment (the high point of the idler pulley eccentric will be in approximately the 9 o'clock position).
  4. Tighten
    Tighten the timing belt idler pulley bolt, while holding the eccentric in place with the J 42069-40 adjustment wrench to prevent movement, to 40 N·m (30 lb ft).

  5. Remove the J 42069-10 crankshaft locking tool and the J 42069-20 checking gauge.
  6. Turn the crankshaft in the engine rotational direction two revolutions with the J 42069 . Stop at 60 degrees BTDC.
  7. Install the J 42069-10 crankshaft locking tool to the crankshaft drive gear with the knurled bolt.
  8. Use the J 42069 to carefully turn the crankshaft until the lever of the J 42069-10 firmly contacts the water pump pulley flange.
  9. Secure the moveable lever of the tool to the water pump pulley flange.
  10. Install the J 42069-20 checking gauge to camshaft gears 1 & 2.
  11. Inspect the alignment of the marks on the camshaft gears in reference to the marks on the J 42069-20 checking gauge.
  12. Repeat the procedure again if the marks do not align.
  13. If camshaft gears 1 and 2 are properly aligned, set the final timing belt tensioner as outlined in Timing Belt Tensioner Adjustment at the end of this procedure.

Marks on Camshaft Gears 1 and 2 Align to the RIGHT of J 42069-20

  1. Loosen the timing belt idler pulley for camshaft gears 1 & 2.

  2. Object Number: 345830  Size: MH
  3. Slacken the timing belt by turning the eccentric on the idler pulley CLOCKWISE with the J 42069-40 adjustment wrench until the marks on the camshaft gears and the marks on the J 42069-20 checking gauge are in alignment (the high point of the idler pulley eccentric will be in approximately the 9 o'clock position).
  4. Tighten
    Tighten the timing belt idler pulley bolt, while holding the eccentric in place with the J 42069-40 adjustment wrench to prevent movement, to 40 N·m (30 lb ft).

  5. Remove the J 42069-10 crankshaft locking tool and the J 42069-20 checking gauge.
  6. Turn the crankshaft in the engine rotational direction two revolutions with the J 42069 . Stop at 60 degrees BTDC.
  7. Install the J 42069-10 crankshaft locking tool to the crankshaft drive gear with the knurled bolt.
  8. Use the J 42069 to carefully turn the crankshaft until the lever of the J 42069-10 firmly contacts the water pump pulley flange.
  9. Secure the moveable lever of the tool to the water pump pulley flange.
  10. Install the J 42069-20 checking gauge to camshaft gears 1 & 2.
  11. Inspect the alignment of the marks on the camshaft gears in reference to the marks on the J 42069-20 checking gauge.
  12. Repeat the procedure again if the marks do not align.
  13. If camshaft gears 1 and 2 are properly aligned, set the final timing belt tensioner as outlined in Timing Belt Tensioner Adjustment at the end of this procedure.

Timing Belt Tensioner Adjustment

Important: The following steps are the COMPLETION of adjusting the timing belt and must not be performed as a stand alone operation.

  1. With the J 42069-10 in place locking the crankshaft at TDC:

  2. Object Number: 345835  Size: MH
    1.1. Loosen the timing belt tensioner eccentric locking nut.
    1.2. Turn the eccentric counterclockwise to full stop, then back until the reference mark is 2-4 mm ABOVE the reference mark on the flange.

    Tighten
    Tighten the timing belt tensioner locking nut to 20 N·m (15 lb ft).

  3. If the timing belt idler pulley bolts for camshafts 3 & 4 and 1 & 2 have not been previously torqued to specification:
  4. Tighten
    Tighten the timing belt idler pulley bolts while holding the eccentric in place with the J 42069-40 Adjusting Wrench to prevent movement, to 40 N·m (30 lb ft).

  5. Remove all checking tools.
  6. As a final inspection, once again rotate the engine in the clockwise direction two revolutions until reaching 60 degrees BTDC.
  7. Install the J 42069-10 crankshaft locking tool to the crankshaft drive gear with the knurled bolt.
  8. Use the J 42069 to carefully turn the crankshaft until the lever of the J 42069-10 firmly contacts the water pump pulley flange.
  9. Secure the moveable lever of the tool to the water pump pulley flange.
  10. Inspect the alignment of the reference marks on the camshaft gears with the notches on the rear timing belt cover, as well as, the mark on the crankshaft gear with the mark on the oil pump housing.
  11. Inspect the alignment of the marks on all four camshaft gears in reference to the marks on the J 42069-20 checking gauge.
  12. Repeat the Timing Belt Timing Procedure again if the marks do not align.
  13. Continue with the engine reassembly if further timing belt adjustment is not needed.

Tools Required

J 42069 Timing Belt Alignment Kit

Installation Procedure


    Object Number: 894697  Size: SH
  1. Position the crank at 60 degrees before TDC.

  2. Object Number: 894209  Size: SH

    Notice: The upper idler pulley (cams 1 & 2) and lower idler puller (cams 3 & 4) use different bolts and spacers of different thickness. The upper idler pulley uses a narrow 5 mm (0.20 in.) thick spacer and a black bolt. The lower idler puller uses a 1 mm (0.40 in.) thick spacer and a silver bolt.

  3. Install the lower idler pulley.
  4. Tighten
    Tighten the idler pulley bolt to 40 N·m (30 lb ft).

  5. Install the upper idler pulley and hand tighten the bolt.

  6. Object Number: 897667  Size: SH
  7. Install the timing belt tensioner and hand tighten the nut and washer.
  8. Important: With camshaft locks installed, verify the distance between the camshaft sprockets with the Green Test Belt located in the J 42069 .

  9. Start at #1 and #2 camshaft sprockets. Route the belt around #1 and #2 sprockets while aligning the belt marks to the marks on the sprockets and the rear cover.
  10. Install the belt around the timing belt tensioner.
  11. Route the belt around the upper idler pulley.
  12. Route the belt around #3 and #4 camshaft sprockets while aligning the belt marks to the marks on the sprockets and the rear cover.
  13. Route the belt around the crankshaft hub sprockets while aligning the marks on the belt to the marks on the crankshaft hub sprocket.

  14. Object Number: 894212  Size: MF
  15. Install the plastic wedge kit tool J42069-30 within the J 42069 to lock the timing belt onto the crankshaft hub sprocket.

  16. Object Number: 894234  Size: SH
  17. With the belt firmly engaged on the crankshaft hub, carefully rotate the crankshaft counterclockwise to get the belt slack on the lower idler pulley side.
  18. Route the belt around the lower idler pulley.

  19. Object Number: 894223  Size: SH
  20. Remove the kit tool J42069-30.

  21. Object Number: 894207  Size: SH
  22. Install the crankshaft locking kit tool J42069-10 within the J 42069 and tighten the lever arm to the water pump pulley flange.

  23. Object Number: 894242  Size: SH
  24. Install the camshaft checking gage to cams 3 and 4 and verify the alignment marks are within 2 mm (0.079 in) of each other.
  25. Install the 3 and 4 camshaft locks, if properly aligned.
  26. Install the camshaft checking gage to cams 1 and 2.

  27. Object Number: 894239  Size: SH
  28. Rotate the #1 camshaft sprocket counterclockwise to remove slack between the 1 and 2, and the 3 and 4 cams.
  29. Important: Ensure that the camshaft timing marks are to the left (retard) side of the checking gage.

  30. Rotate the upper idler pulley counterclockwise until the marks are properly aligned within 2 mm (0.079 in) of each other.
  31. Install the 1 and 2 camshaft locks when properly aligned.
  32. Tighten
    Tighten the upper pulley bolt to 40 N·m (30 lb ft).


    Object Number: 895597  Size: SH
  33. Adjust the timing belt tensioner so that the center alignment mark is about 3 mm (1/8 in) above the alignment mark on the spring loaded idler.

  34. Object Number: 894234  Size: SH
  35. Remove the 1-2 and the 3-4 camshaft lock kit tools J42069-1 and J42069-2.
  36. Remove the kit tool J42069-10.
  37. Important: If TDC is passed, do not rotate the crankshaft counterclockwise. This will not allow proper slack to be taken up between the timing belt tensioner and the crankshaft sprocket. To correct this, rotate the crankshaft an additional 2 turns.

  38. Rotate the crankshaft 1 3/4 turns clockwise. Install the crankshaft locking kit tool J42069-10 within the J 42069 , and then stop at TDC.

  39. Object Number: 894207  Size: SH
  40. Tighten the lever arm to the water pump pulley flange.

  41. Object Number: 894231  Size: SH
  42. Install the checking gage kit tool J42069-20 within the J 42069 and verify the marks are within 2 mm (0.079 in) of each other.

  43. Object Number: 895597  Size: SH
  44. Adjust the timing belt tensioner so that the center alignment mark is about 3 mm (1/8 in) above the alignment mark on the spring loaded idler.
  45. Tighten the timing belt tensioner.
  46. Tighten
    Tighten the timing belt tensioner fastening nut to 20 N·m (15 lb ft).

  47. Remove the J42069-10 and the J42069-20..