GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Colorado Pickup - 2WD 🢒 Engine 🢒 Engine Mechanical - 3.5L (L52) 🢒 Camshaft Timing Chain and Sprocket Replacement

Tools Required

    • J 44221 Camshaft Holding Tool
    • J 45059 Angle Meter

Removal Procedure
  1. Remove #1 cylinder spark plug. Refer to Spark Plug Replacement for the 3.5L (L52) engine.
  2. Remove the camshaft cover. Refer to Camshaft Cover Replacement .
  3. Remove the exhaust camshaft position (CMP) sensor. Refer to Camshaft Position Sensor Replacement - Exhaust for the 3.5L (L52) engine.
  4. Remove the intake camshaft position (CMP) sensor. Refer to Camshaft Position Sensor Replacement - Intake for the 3.5L (L52) engine.
  5. Remove the engine front cover. Refer to Engine Front Cover Replacement .
  6. Rotate the crankshaft in the engine rotational direction clockwise, until the #1 piston is at top dead center (TDC) on the compression stroke.

    7. Caution: Refer to Camshaft Holding Tool Caution in the Preface section.


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

    8. Object Number: 760721 Size: SH
  8. Release the tension on the timing chain by moving the tensioner shoe in.

    9. Object Number: 760718 Size: SH
  9. Place the tee into the tensioner to hold the shoe in place.

    10. Object Number: 1619812 Size: SH
  10. Remove the exhaust camshaft position actuator bolt.

    11. Discard the bolt.

  11. Remove the exhaust camshaft position actuator.

    12. Object Number: 637575 Size: SH
  12. Remove the intake camshaft sprocket bolt.

    13. Discard the bolt.

  13. Remove the intake camshaft sprocket.
  14. Remove the timing chain.
  15. Remove the crankshaft sprocket.
  16. Clean and inspect the timing chain and sprockets. Refer to Camshaft Timing Chain and Sprocket Cleaning and Inspection .

Installation Procedure

    Object Number: 637578 Size: SH

    Important: Ensure the #1 piston is at TDC. The pin on the crankshaft for the timing chain sprocket should be straight up.

  1. Install the crankshaft sprocket to the crankshaft snout.

    2. Important: Every 7th link of the timing chain is darkened to aid in aligning the timing marks.

  2. Install the intake camshaft sprocket into the timing chain.

    3. Aligning the dark link (1) of the timing chain with the timing mark on the intake camshaft sprocket.

  3. Feed the timing chain down through the opening in the cylinder head.
  4. Install the timing chain on the crankshaft sprocket.

    5. Aligning the dark link (2) of the timing chain with the timing mark on to the crankshaft sprocket.

    Important: Ensure the alignment pin is properly engaged with the camshaft

  5. Install the intake camshaft sprocket onto the intake camshaft.

    6. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 748325 Size: SH
  6. Install the new intake camshaft sprocket bolt.

    7. Tighten

    1. Tighten the intake camshaft sprocket bolt to 20 N·m (15 lb ft).
    2. Use the J 45059 to rotate the intake camshaft sprocket bolt an additional 100 degrees.
  7. Ensure the camshaft actuator is fully advanced prior to installation. Refer to Camshaft Position Actuator Diagnosis .

    8. Object Number: 1619822 Size: SH
  8. Install the exhaust camshaft actuator into the timing chain.

    9. Align the dark link (1) of the timing chain with the timing mark (1) on the exhaust camshaft position actuator sprocket.

    Notice: The camshaft actuator must be fully advanced during installation. Engine damage may occur if the camshaft actuator is not fully advanced.

    Important: 

       • To aid in aligning the actuator 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

  9. Install the exhaust camshaft actuator onto the exhaust camshaft.

    10. Object Number: 1619812 Size: SH
  10. Install the new exhaust camshaft actuator bolt.

    11. Tighten

    1. Tighten the exhaust camshaft actuator bolt to 25 N·m (18 lb ft).
    2. Use the J 45059 to rotate the exhaust camshaft actuator bolt an additional 135 degrees.

    Object Number: 760718 Size: SH
  11. Remove the tee in the timing chain tensioner to regain tension on the timing chain.

    12. Object Number: 858336 Size: SH
  12. Remove the J 44221 from the camshafts.

    13. Object Number: 1619825 Size: SH
  13. The dark links (1) on the timing chain should be aligned with the marks on the sprockets as shown.
  14. Install the engine front cover. Refer to Engine Front Cover Replacement .
  15. Install the intake camshaft position (CMP) sensor. Refer to Camshaft Position Sensor Replacement - Intake for the 3.5L (L52) engine.
  16. Install the exhaust camshaft position (CMP) sensor. Refer to Camshaft Position Sensor Replacement - Exhaust for the 3.5L (L52) engine.
  17. Install the camshaft cover. Refer to Camshaft Cover Replacement .
  18. Install #1 cylinder spark plug. Refer to Spark Plug Replacement for the 3.5L (L52) engine.