GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J-44217-45 Chain Holding Tool
    • J 44217 Timing Chain Retention Tool
    • J 44221 Camshaft Holding Tool
    • J 45059 Angle Meter

Removal Procedure

  1. Remove the camshaft cover. Refer to Camshaft Cover Replacement .
  2. Remove the intake camshaft position (CMP) sensor. Refer to Camshaft Position Sensor Replacement - Intake .
  3. Rotate the crankshaft in the engine rotational direction clockwise, until the #1 piston is at top dead center (TDC) on the compression stroke.
  4. Using the timing mark on the intake camshaft sprocket as a reference, make a mark on the timing chain link adjacent to it.
  5. Caution: Refer to Camshaft Holding Tool Caution in the Preface section.


    Object Number: 858336  Size: SH
  6. Install the J 44221 to the rear of the camshafts.

  7. Object Number: 812952  Size: SH
  8. Complete the following in order to install the J 44217  (1) and J-44217-45  (1).
  9. 6.1. Install the hook portion of the timing chain retention tools into one of the timing chain links near the timing chain shoe on both sides of the engine.
    6.2. Tighten the wingnuts.
    6.3. Ensure the hooks are still in one of the links and the gage blocks of the tool are firmly in place on the edge of the head.

    Object Number: 748325  Size: SH
  10. Remove and discard the intake camshaft sprocket bolt.
  11. Remove the intake camshaft sprocket.

Installation Procedure


    Object Number: 1619825  Size: SH
  1. Install the intake camshaft sprocket into the timing chain.
  2. Aligning the marked link (1) on the timing chain with the timing mark on the intake camshaft sprocket.

    Important: 

       • To aid in aligning the sprocket to the camshaft , use a 25 mm (1 in) wrench on the hex of the camshaft to rotate.
       • Ensure the alignment pin is properly engaged with the camshaft.

  3. Install the intake camshaft sprocket onto the intake camshaft.
  4. Notice: Refer to Fastener Notice in the Preface section.

  5. Install the new intake camshaft sprocket bolt.
  6. Tighten
    Tighten the bolt to 20 N·m (15 lb ft) plus an additional 100 degrees using the J 45059 .


    Object Number: 812952  Size: SH
  7. Remove the J 44217  (1) and J-44217-45  (1).

  8. Object Number: 858336  Size: SH
  9. Remove the J 44221 from the camshafts.
  10. Install the intake CMP sensor. Refer to Camshaft Position Sensor Replacement - Intake .
  11. Install the camshaft cover. Refer to Camshaft Cover Replacement .