- Install the upper main bearings into the cylinder block and lubricate with engine oil.
- Install the lower main bearings into the lower crankcase and lubricate with engine oil.
- Install the two upper thrust bearing washers into the cylinder block and lubricate with engine oil.
- Carefully place the crankshaft (1) on to the main bearings in the cylinder block.
- Thoroughly clean and remove any oil residue from the cylinder block mating surfaces.
- Apply a continuous bead of GM P/N 12345997 or equivalent sealant to the cylinder block mating rails.
- Carefully place the lower crankcase assembly on to the cylinder block.
- Gently tap the lower crankcase into place with a suitable tool.
- Install the long 8 mm bolt (3) finger tight.
- Install the 8 mm bolts (2) finger tight.
- Install the 10 mm bolts (1) finger tight.
- Progressively torque the 10 mm main bearing cap bolts using two steps in the sequence shown.
- Progressively torque the lower crankcase bolts using two steps.
- Inspect that the crankshaft rotates smoothly by hand.
Important: The upper main bearings have an oil groove and oil holes, the lower bearings do not have oil grooves or oil holes.
Important: Install the upper thrust bearing washers (1) with the oil groove (2) facing outward.
Important: Avoid applying an excessive amount of sealant to the surface.
Important: Gradual and uniform tightening is important for the lower crankcase bolts.
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.
1st Pass
Tighten the main bearing cap bolts to 42 N·m (31 lb ft).
2nd Pass
Tighten the main bearing cap bolts to 58 N·m (42 lb ft).
1st Pass
Tighten the lower crankcase bolts to 19 N·m (14 lb ft).
2nd Pass
Tighten the lower crankcase bolts to 27 N·m (20 lb ft).
