For 1990-2009 cars

### 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. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
3. Place a drain pan or suitable container underneath the engine oil pan.
4. Remove the engine oil drain plug and gasket. Allow the engine oil to drain.
5. Remove the following components from the vehicle:

• | Fourteen bolts

• | Two nuts

• | Crankshaft position sensor

• | The engine oil pan

6. Remove the following components from the vehicle:

• | Eight main bearing bolts

• | Four main bearing caps with lower inserts

7. Remove the four upper inserts from the cylinder block.
8. Inspect the main bearings for pitting, scratches, wear or damage. Replace both of the upper and lower halves of the main bearings if any of these conditions are found. Any time the main bearings must be replaced, both the upper and lower half should be replaced as a set. Do not replace only one of the halves.

### Installation Procedure

Important: The upper insert has an engine oil groove. Install the insert with the engine oil groove to the cylinder.

1. Install the upper inserts (2) to the cylinder block (1).

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: Lightly oil the main bearing cap bolts prior to installation. Gradual and uniform tightening is important for main bearing bolts. After tightening the main bearing cap bolts, inspect in order to check that the crankshaft rolls smoothly when turned by hand.

2. Install the main bearing caps with the lower inserts and secure with the eight main bearing cap bolts. Each main bearing cap is embossed with an arrow mark and a number. When installing each bearing cap to the cylinder block, point the arrow mark toward the crankshaft timing pulley side and in order 1, 2, 3 and 4. Tighten the main bearing caps.

Tighten
Tighten the main bearing cap bolts to 54 N·m (40 lb ft).

3. Install the oil pump strainer and the oil pump strainer seal to the cylinder block and secure with the oil pump strainer bolt first and then the oil pump strainer bracket bolt.

Tighten
Tighten the oil pump strainer bolt first and then the oil pump strainer bracket bolt to 11 N·m (8 lb ft).

4. Apply a continuous bead of GM P/N 12346240 or equivalent, to the engine oil pan mating surface.
5. Install the engine oil pan to the cylinder block and secure the engine oil pan with fourteen bolts and two nuts starting at the center and working outward.

Tighten
Tighten the engine oil pan bolts and nuts to 11 N·m (97 lb in).

6. Install the gasket and the engine oil pan drain plug.

Tighten
Tighten the engine oil drain plug to 35 N·m (26 lb ft).

7. Install the crankshaft position sensor.

Tighten
Tighten the crankshaft positon sensor bolt to 11 N·m (97 lb in).

8. Lower the vehicle.
9. Fill the engine oil to specifications. Refer to Approximate Fluid Capacities in Maintenance and Lubrication.
10. Connect the negative battery cable.
11. Inspect coolant system for leaks.
12. Start the engine. Inspect the exhaust system for exhaust leaks.
13. Run the engine in order to inspect the engine oil pressure.