Important: The upper main bearings have an oil groove and oil holes, the lower
bearings do not have oil grooves or oil holes.
- 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.
Important: Install the upper thrust bearing washers with the oil groove (2) facing
outward.
- Install the two upper thrust bearing washers into the cylinder block
and lubricate with engine oil.
- Install the oil pump drive
chain to the crankshaft gear.
- Carefully place the crankshaft on to the main bearings in the
cylinder block.
- Thoroughly clean and remove
any oil residue from the cylinder block mating surfaces.
Important: Avoid applying an excessive amount of sealant to the surface.
- 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.
Important: Gradual and uniform tightening is important for the lower crankcase
bolts.
- Install the ten main bearing cap bolts finger tight.
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.
- Progressively torque
the main bearing cap bolts (1-10) using two steps in the sequence shown.
Tighten
- Tighten the main bearing cap bolts (1-10) to 42 N·m
(31 lb ft).
- Tighten the main bearing cap bolts (1-10) to 60 N·m
(44 lb ft).
- Install the twelve lower crankcase bolts. Progressively torque
the lower crankcase bolts (11-22) using two steps in the sequence shown.
Tighten
- Tighten the twelve lower crankcase bolts (11-22) to 19 N·m
(14 lb ft).
- Tighten the twelve lower crankcase bolts (11-22) to 27 N·m
(20 lb ft).
- Inspect that the crankshaft rotates smoothly by hand.