GM Service Manual Online
For 1990-2009 cars only

Special Tools

    •  J 5590 Bearing and Seal Driver
    •  J 5825-A Crankshaft Gear Remover

Removal Procedure


    Object Number: 480575  Size: SH
  1. Remove the crankshaft position (CKP) sensor reluctor ring. Refer to Crankshaft Position Sensor Reluctor Ring Replacement.
  2. Install a 7/16-20 x 1 inch bolt into the end of the crankshaft.
  3. Caution: Align the timing marks before removing the timing chain. If it is necessary to turn either the camshaft or the crankshaft with the timing chain removed, loosen or remove the valve rocker arms. Turning either the crankshaft or camshaft with the timing chain removed may cause the pistons to contact the valves, resulting in damage.

  4. Rotate the crankshaft until:
  5. • The timing marks on both sprockets line up.
    • The number 4 cylinder is at top dead center (TDC) of the compression stroke.

    Object Number: 1254416  Size: SH
  6. Unsnap the timing chain tensioner shoe from the pin (1).

  7. Object Number: 869743  Size: SH
  8. Remove the camshaft sprocket bolts.

  9. Object Number: 869746  Size: SH
  10. Remove the camshaft sprocket and the camshaft timing chain.

  11. Object Number: 869747  Size: SH
  12. Using J 5825-A and an open end wrench, remove the crankshaft sprocket.

  13. Object Number: 869734  Size: SH
  14. Remove the crankshaft balancer key.

  15. Object Number: 1254412  Size: SH
  16. If necessary, remove the timing chain tensioner bracket bolt and bracket.
  17. Clean and inspect the timing chain and sprockets, if necessary. Refer to Camshaft Timing Chain and Sprocket Cleaning and Inspection.

Installation Procedure

    Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1254412  Size: SH
  1. If necessary, install the timing chain tensioner bracket and bolt and tighten the bolt to 12 N·m (106 lb in).

  2. Object Number: 869734  Size: SH
  3. Install the key into the crankshaft keyway.
  4. The crankshaft balancer key should be parallel to the crankshaft or with a slight incline.


    Object Number: 869749  Size: SH
  5. Align the keyway of the crankshaft sprocket with the crankshaft balancer key.
  6. Using J 5590 , install the crankshaft sprocket.

  7. Object Number: 869746  Size: SH

    Note: Install the camshaft sprocket with the alignment mark at the 6 o'clock position.

  8. Install the camshaft sprocket and the camshaft timing chain. Wrap the timing chain around the crankshaft sprocket and position to the driver side of the engine.

  9. Object Number: 1254420  Size: SH
  10. Install the timing chain tensioner shoe onto the bracket and position the top of the shoe under the tab at the top of the bracket.

  11. Object Number: 869743  Size: SH
  12. Insert the camshaft timing chain sprocket into the timing chain and position so when the camshaft timing chain sprocket is installed on the camshaft, the camshaft timing marks will line up.
  13. Note:  Do not use a hammer to install the camshaft sprocket onto the camshaft. To do so may dislodge the expansion cup plug.

  14. Install the camshaft sprocket bolts and tighten to 25 N·m (18 lb ft).

  15. Object Number: 480575  Size: SH
  16. Ensure that the crankshaft sprocket is aligned at the 12 o'clock position and camshaft sprocket is aligned at the 6 o'clock position.
  17. Remove the bolt that was installed in the end of the crankshaft.
  18. Install the CKP sensor reluctor ring. Refer to Crankshaft Position Sensor Reluctor Ring Replacement.