GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Remove the engine oil pan and the oil pump strainer from the cylinder block. Refer to Cylinder Head Replacement in this section.
  2. Remove the following components:
  3. • Ten bolts
    • The bearing cap supports
    • The main bearing caps
    • The main bearing lower half

    Object Number: 166744  Size: SH

    Important: Any time the main bearings must be replaced, both the upper and lower half should be replaced as a set. Never replace only one of the halves.

  4. Remove the main bearing upper half (3).
  5. Inspect the main bearings for the following:
  6. • Pitting
    • Scratches
    • Wear
    • Damage
    • Replace both the upper and lower halves of the main bearings if any of these conditions are found.

Installation Procedure


    Object Number: 166744  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.

    Important: The main bearing upper half has an oil groove (2). Install the main bearing upper half (3) with the oil groove to the cylinder (1).

  1. Install the main bearing upper half (3) with the oil groove to the cylinder (1).

  2. Object Number: 166742  Size: SH

    Important: Gradual and uniform tightening is important for the main bearing cap bolts.

    Important: After tightening the main bearing bolts, check to be sure that the crankshaft rotates smoothly when turned by hand.

  3. Install the bearing cap supports and the main bearing caps to the cylinder block. Install each of the caps in ascending order of numbers 1, 2, 3, 4 and 5. Start from crankshaft pulley side (2) and continue through to the flywheel side (1). Ensure that all of the arrow marks point toward the crankshaft pulley side.
  4. Tighten
    Tighten the main bearing cap bolts to 54 N·m (40 lb ft).

  5. Install the oil pump strainer and the engine oil pan to the cylinder block.