GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 45027 Tensioner Tool

Removal Procedure

  1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
  2. Remove the camshaft cover. Refer to Camshaft Cover Replacement.

  3. Object Number: 412158  Size: SH
  4. Remove the timing chain tensioner.
  5. Remove the seal from the tensioner.

Installation Procedure


    Object Number: 714496  Size: SH
  1. Inspect the timing chain tensioner. If the timing chain tensioner, O-ring seal, or washer is damaged, replace the timing chain tensioner or O-ring seal as applicable.
  2. Measure the timing chain tensioner assembly from end to end. If the timing chain tensioner is to be replaced, a new tensioner should be supplied in the fully compressed non-active state. A tensioner in the compressed state will measure 72 mm (2.83 in) (a) from end to end. A tensioner in the active state will measure 85 mm (3.35 in) (a) from end to end.

  3. Object Number: 797246  Size: SH
  4. If the timing chain tensioner is not in the compressed state, perform the following steps:
  5. 3.1. Remove the piston assembly from the body of the timing chain tensioner by pulling it out.
    3.2. Install the J 45027-2 (2) into a vise.
    3.3. Install the notch end of the piston assembly into the J 45027-2 (2).
    3.4. Using the J 45027-1 (1), turn the ratchet cylinder into the piston.

    Object Number: 714496  Size: SH
  6. Inspect the bore of the tensioner body for dirt, debris, and damage. If any damage appears, replace the tensioner. Clean dirt or debris out with a lint-free cloth.
  7. Install the compressed piston assembly back into the timing chain tensioner body until it stops at the bottom of the bore. Do not compress the piston assembly against the bottom of the bore. If the piston assembly is compressed against the bottom of the bore, it will activate the tensioner, which will then need to be reset again.
  8. At this point the tensioner should measure approximately 72 mm (2.83 in) (a) from end to end. If the tensioner does not read 72 mm (2.83 in) (a) from end to end, repeat steps 3-5.

  9. Object Number: 412158  Size: SH
  10. Inspect to ensure all dirt and debris is removed from the timing chain tensioner threaded hole in the cylinder head.
  11. Notice: Refer to Fastener Notice in the Preface section.

    Important: Ensure the timing chain tensioner seal is centered throughout the torque procedure to eliminate the possibility of an oil leak.

  12. Install the timing chain tensioner assembly.
  13. Tighten
    Tighten the timing chain tensioner to 75 N·m (55 lb ft).

  14. The timing chain tensioner is released by compressing the tensioner 2 mm (0.079 in) which will release the locking mechanism in the ratchet. To release the timing chain tensioner, use a suitable tool with a rubber tip on the end. Feed the tool down through the cam drive chest to rest on the cam chain. Then give a sharp jolt diagonally downwards to release the tensioner.
  15. Install the camshaft cover. Refer to Camshaft Cover Replacement.
  16. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.