GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Tracker - 2WD 🢒 Engine 🢒 Engine Mechanical - 2.5L (LE8) 🢒 Secondary Timing Chain Replacement - Left Side

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Remove the engine front cover. Refer to Engine Front Cover Replacement .
  3. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls -2.5L.

    4. Object Number: 648539 Size: MH

    Notice: Avoid turning the camshafts and the crankshaft once the timing chain or timing chain tensioner is removed. Valve and piston damage may occur.

    Important: The timing marks must be correctly aligned before disassembly in order to correctly install the timing chains.

  4. Rotate the crankshaft so that the following conditions are met:
    5. • The keyway on the crankshaft (3) is properly positioned.
    • The arrow (2) on the idler sprocket is pointing to the crankshaft.
    • The marks on the sprockets (1) match up with the marks on the cylinder head.
  5. Remove the 3 bolts and the upper chain guide.

    6. Object Number: 648565 Size: SH
  6. Remove the 1 nut and 2 bolts from the timing chain tensioner (1).
  7. Remove the timing chain tensioner (1). It may be necessary to slacken the timing chain by turning the intake camshaft (2) counterclockwise a little while pushing back on the tensioner pad.

    8. Object Number: 648553 Size: SH
  8. Hold the camshafts (2) with a wrench and remove the camshaft sprocket bolts.
  9. Remove the camshaft sprockets (1,3) and timing chain.

    10. Object Number: 648578 Size: SH
  10. Remove the 2 bolts (1) and the side chain guide (2).
  11. Inspect the following components for wear and damage:
    12. • The camshaft timing chain guides 
    • The camshaft timing chain tensioner
    • The camshaft timing chain sprockets
    • The camshaft timing chain

    Object Number: 648155 Size: SH
  12. Verify that the latch (1) and teeth (2) of the timing chain tensioner are undamaged and that the tensioner functions correctly.
  13. Replace any worn or damaged component.

Installation Procedure

    Object Number: 648577 Size: SH
  1. Verify that the keyway on the crankshaft (2) is properly positioned.

    2. Object Number: 648543 Size: SH
  2. Verify that the timing mark (2) on the idler sprocket (1) is properly positioned.

    3. Object Number: 648578 Size: SH

    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.

  3. Install the side chain guide (2). Secure with the 2 bolts (1).

    4. Tighten
    Tighten the bolts to 11 N·m (7.5 lb ft).


    Object Number: 648637 Size: SH
  4. Verify that the knock-pin (1) of the intake camshaft and knock-pin (3) of the exhaust camshaft are aligned with the match marks on the cylinder head.

    5. Object Number: 648632 Size: SH
  5. Install the timing chain to the idler sprocket by aligning the yellow link (1) of the timing chain with the mark (2) on the idler sprocket.

    6. Object Number: 648551 Size: MH
  6. Install the sprockets to the camshafts by aligning the silver links (1) with the mark on the intake sprocket (3) and the exhaust sprocket (2).
  7. Secure the sprocket with the bolts (4) while holding the camshafts with a wrench.

    8. Tighten
    Tighten the 2 bolts to 80 N·m (57.5 lb ft).


    Object Number: 648156 Size: SH
  8. With the latch (2) of the tensioner adjuster returned and the plunger (1) pushed back into the body, insert a retainer (4) (paper clip or similar tool) into the set hole (3). After inserting the pin, make sure the plunger will not come out.

    9. Object Number: 648563 Size: SH
  9. Install the timing chain tensioner (3). Secure with the bolt (1).

    10. Tighten
    Tighten the bolt to 12 N·m (8.5 lb ft).

  10. Install tensioner nut (4).

    11. Tighten
    Tighten the nut to 45 N·m (32.5 lb ft).

  11. Install tensioner nut (5).

    12. Tighten
    Tighten the nut to 45 N·m (32.5 lb ft).

  12. Remove the retainer (2) from the tensioner.
  13. Install the upper chain guide. Secure with the 3 bolts.

    14. Tighten
    Tighten the bolts to 11 N·m (7.5 lb ft).

  14. Turn the crankshaft 2 revolutions clockwise.

    15. Object Number: 648767 Size: MH
  15. Align the keyway (8) on the crankshaft with the oil jet (7).
  16. Verify that all the other timing marks are properly aligned.
  17. Apply engine oil to the following:
    18. • The timing chains
    • The tensioner
    • The guides
    • The sprockets
  18. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 2.5L.
  19. Install the engine front cover. Refer to Engine Front Cover Replacement .
  20. Connect the negative battery cable.