GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 Century 🢒 Engine 🢒 Engine Mechanical - 3.1L 🢒 Camshaft Timing Chain and Sprocket Replacement

Removal Procedure
  1. Remove the engine front cover. Refer to Engine Front Cover Replacement .

    2. Object Number: 644213 Size: SH
  2. Rotate the crankshaft until the timing marks in the following locations are aligned:
    3. • The timing chain dampener to the crankshaft sprocket (2).
    • The timing chain dampener to the camshaft sprocket locator hole (1).

    Object Number: 190538 Size: SH
  3. Remove the camshaft sprocket bolt.

    4. Object Number: 190539 Size: SH
  4. Remove the camshaft sprocket with the timing chain.

    5. Object Number: 760405 Size: SH
  5. Remove the crankshaft sprocket.

    6. Object Number: 59271 Size: SH
  6. Remove the timing chain dampener bolts.
  7. Remove the timing chain dampener.

    8. Object Number: 96021 Size: SH
  8. If necessary remove the camshaft thrust plate screws.
  9. Remove the camshaft thrust plate.

Installation Procedure

    Object Number: 96021 Size: SH
  1. If removed install the camshaft thrust plate.

    2. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  2. Install the camshaft thrust plate screws.

    3. Tighten
    Tighten the screws to 10 N·m (89 lb in).


    Object Number: 59271 Size: SH
  3. Install the timing chain dampener and the bolts to the block.

    4. Tighten
    Tighten the bolts to 21 N·m (15 lb ft).


    Object Number: 760405 Size: SH
  4. Install the crankshaft sprocket.
  5. Apply Engine Oil Supplement (EOS) GM P/N 1052367 (Canadian P/N 992869) or the equivalent to the sprocket thrust surface.

    6. Object Number: 190539 Size: SH
  6. Hold the camshaft sprocket with the chain hanging down, and install the chain to the crankshaft gear.

    7. Object Number: 644213 Size: SH
  7. Align the crankshaft timing mark to the timing mark on the bottom of the timing chain dampener (2).
  8. Hold the camshaft sprocket with the timing chain hanging down and install the timing chain to the crankshaft gear.
  9. Align the timing mark on the camshaft gear with the timing mark on top of the timing chain dampener (1).

    10. Object Number: 190538 Size: SH

    Important:  Draw the camshaft sprocket onto the camshaft using the mounting bolt.

  10. Install the camshaft sprocket bolt.

    11. Tighten
    Tighten the bolt to 140 N·m (103 lb ft).

  11. Coat the crankshaft and the camshaft sprocket with engine oil.
  12. Install the engine front cover. Refer to Engine Front Cover Replacement .