GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • EN-46105 Camshaft Locking Tool
    • EN-46111 Crankshaft Rotation Socket
    • EN-46112 Tensioner Retraction Pins

Removal Procedure


    Object Number: 1796549  Size: SH
  1. Remove the primary timing chain. Refer to Primary Camshaft Drive Chain and Sprockets Replacement.
  2. Note: Take care when removing the tensioner bolts. The tensioner plunger is subjected to spring tension and may spring apart during tensioner removal.

  3. Remove the two bank 2 secondary timing chain tensioner bolts (1) and remove the tensioner (2).

  4. Object Number: 1796550  Size: SH
  5. Remove the gasket (1) from the tensioner (2) and discard the gasket.
  6. Inspect the tensioner mounting surface on the bank 2 cylinder head for burrs or any defects that would affect the sealing of a new tensioner gasket.

  7. Object Number: 1796558  Size: SH
  8. Remove the bank 2 secondary timing chain shoe bolt (1).

  9. Object Number: 1796560  Size: SH
  10. Remove the bank 2 secondary timing chain shoe (1).

  11. Object Number: 1796563  Size: SH
  12. Remove the bank 2 secondary timing chain guide bolt (1), two places, and remove the guide (2).

  13. Object Number: 1796565  Size: SH
  14. Remove the bank 2 secondary timing chain (1) from the camshaft position actuators and the camshaft intermediate driveshaft sprocket.

  15. Object Number: 1796573  Size: SH
  16. If required, remove the bank 2 camshaft intermediate driveshaft sprocket bolt (1) and remove the sprocket (2).

  17. Object Number: 1796578  Size: SH
  18. Remove EN-46105-2 (1) from the bank 2 cylinder head camshafts (2).

  19. Object Number: 1796633  Size: SH
  20. Remove EN-46105-1 (1) from the bank 1 cylinder head camshafts (2).
  21. Clean and inspect the timing chain sprockets. Refer to Camshaft Timing Drive Components Cleaning and Inspection.

Installation Procedure


    Object Number: 1796699  Size: SH
  1. Ensure that the crankshaft sprocket is installed with the timing mark (1) visible.

  2. Object Number: 1796545  Size: SH
  3. Install the crankshaft sprocket (1) onto the crankshaft (2) by aligning the keyway to the key on the crankshaft.
  4. Slide the crankshaft sprocket on the crankshaft until the crankshaft sprocket contacts the step in the crankshaft.
  5. In order to install EN-46105 tool onto the camshafts, rotate the camshafts in an counterclockwise direction. There should be no need to rotate the camshaft more than 45 degrees.

  6. Object Number: 1797019  Size: SH
  7. Install EN-46105-1 (1) onto the rear of the bank 2 cylinder head camshafts (2), and EN-46105-2 onto the rear of the bank 1 cylinder head camshafts.
  8. Note: All camshafts must be locked in place before installation of any timing chains.

  9. Ensure that EN-46105 tool is fully seated onto the camshafts.

  10. Object Number: 1797021  Size: SH
  11. Using EN-46111 socket  (1), rotate the crankshaft in a clockwise direction until the crankshaft sprocket timing mark (2) is aligned with the indexing mark (3) on the oil pump housing.

  12. Object Number: 1797023  Size: SH
  13. Install the bank 2 secondary timing chain (1) aligning the chain.

  14. Object Number: 1797029  Size: SH
  15. Wrap the secondary timing chain around both bank 2 actuator drive sprockets.
  16. Ensure there are two bright links located on top of each of the camshaft actuator sprockets.

  17. Object Number: 1797041  Size: SH

    Note: When aligning the bank 2 secondary timing chain to the camshaft actuator sprockets, ensure the circular timing marks on the sprocket are used, NOT the triangular mark.

  18. Align the bright plated timing chain link (1) with the bank 2 exhaust camshaft position actuator sprocket alignment circle mark (2).

  19. Object Number: 1797033  Size: SH
  20. Align the bright plated timing chain link (1) with the intake camshaft position actuator sprocket alignment circle mark (2).

  21. Object Number: 1797042  Size: SH

    Note: The bank 2 camshaft intermediate driveshaft sprocket (1) is marked with the letters LB and ’FRONT’, and the bank 1 sprocket (2) is marked with the letters RB and ’FRONT’ Ensure the correct sprocket is used and the ’FRONT’ text is facing forwards when installed.

  22. Ensure the bank 2 camshaft intermediate driveshaft sprocket is selected and orientated correctly.

  23. Object Number: 1797051  Size: SH
  24. Place the bank 2 secondary timing chain around the left-hand camshaft intermediate driveshaft inner sprocket, with the bright plated timing chain link (1) aligned with the access hole (2) in the outer sprocket.
  25. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1797056  Size: SH
  26. Install the bank 2 camshaft intermediate driveshaft sprocket to the cylinder block and tighten the bolt to 66 N·m (49 lb ft).

  27. Object Number: 1797059  Size: SH
  28. Verify the bank 2 secondary timing chain timing mark alignments (1-6).
  29. Note: The bank 2 secondary timing chain guide is marked with the letters LH. Ensure the correct shoe is used when installing to the bank 2 side in this procedure and that the letters ’LH" are facing the front of the vehicle when installed.

  30. Ensure the bank 2 secondary timing chain guide is selected and orientated correctly.

  31. Object Number: 1796563  Size: SH
  32. Install the bank 2 secondary timing chain guide (1) and tighten the attaching bolt to 23 N·m (17 lb ft).

  33. Object Number: 1797069  Size: SH

    Note: The bank 2 secondary timing chain shoe  (2) is marked with the letters LH on the back face of the timing chain shoe. Ensure the correct shoe is used when installing to the bank 2 side.

  34. Ensure the bank 2 secondary timing chain shoe is selected and orientated correctly.

  35. Object Number: 1797073  Size: SH

    Note: Ensure secondary timing chain shoe is clear of the Bank 2 secondary timing chain tensioner mounting pad, before tightening the attaching bolt.

  36. Install the bank 2 secondary timing chain shoe (1) and tighten bolt to 23 N·m (17 lb ft).

  37. Object Number: 1797079  Size: SH
  38. Ensure the bank 2 secondary timing chain tensioner is selected and orientated correctly.

  39. Object Number: 1797087  Size: SH

    Note: To reset the tensioner, use a suitably sized flat-bladed screwdriver (1) to wind the plunger in a clockwise direction, into the tensioner shaft (2).

  40. Reset the bank 2 secondary timing chain tensioner.

  41. Object Number: 1797090  Size: SH
  42. Install the tensioner shaft (1) into the bank 2 secondary timing chain tensioner body (2).

  43. Object Number: 1797091  Size: SH

    Note: If EN-46112 pins  (1) is not inserted into the tensioner body (2), the tensioner shaft (3) will remain in the locked position and no tension will be placed on the timing chain, this will cause damage to the engine.

  44. Compress the tensioner shaft into the body and lock the bank 2 secondary timing chain tensioner by inserting EN-46112 pins into the access hole in the side of the tensioner body.
  45. Slowly release pressure on the bank 2 secondary timing chain tensioner. The tensioner should remain compressed.

  46. Object Number: 1797092  Size: SH
  47. Install a new bank 2 secondary timing chain tensioner gasket (1) to the tensioner (2).
  48. Install the bank 2 secondary timing chain tensioner bolts through tensioner and gasket.
  49. Ensure the bank 2 secondary timing chain tensioner mounting surface on the Bank 2 cylinder head does not have any burrs or defects that would affect the sealing of the new gasket.

  50. Object Number: 1796549  Size: SH
  51. Place the bank 2 secondary timing chain tensioner (2) into position and loosely install the bolts (1) to the cylinder head.

  52. Object Number: 1797150  Size: SH
  53. Verify the proper placement of the bank 2 secondary timing chain tensioner gasket tab (1).
  54. Tighten the bank 2 secondary timing chain tensioner bolts (2) to 23 N·m (17 lb ft).

  55. Object Number: 1797157  Size: SH
  56. Release the bank 2 secondary timing chain tensioner (1) by pulling out EN-46112 pins  (2) and unlocking the tensioner shaft.

  57. Object Number: 1797159  Size: SH
  58. Verify the bank 2 secondary timing chain timing mark alignments (1-6).
  59. Install the primary timing chain. Refer to Primary Camshaft Drive Chain and Sprockets Replacement.