Main Bearing

If the rear main bearing is to be replaced, it will be necessary to remove the engine, install it on a work stand, replace the main bearing and replace the crankshaft rear oil seal.

The main bearing inserts are selective fit. Refer to procedures under Fitting Main and Connecting Rod Bearings in Section 03-00.

Tools Required:

• Main Bearing Insert Tool TOOL-6331-E

Removal

1. Drain the crankcase. Remove the oil level dipstick. Remove the oil pan and related parts.

2. Remove the oil pump inlet tube assembly and the oil pump.

3. Replace one bearing at a time, leaving the other bearings securely fastened.

   Remove the main bearing cap to which new bearings are to be installed.

4. Insert the Main Bearing Insert Tool TOOL-6331-E or equivalent, in the oil hole in the crankshaft.

5. Rotate the crankshaft in the direction of the engine rotation to force the bearing out of the block.

6. Clean the crankshaft journals. Inspect the journals and thrust faces (thrust bearing) for nicks, burrs or bearing pickup that would cause premature bearing wear.

7. If the rear main bearing is being replaced, remove and discard the rear oil seal.

8. Repeat Steps 3 through 7 for the remaining bearings to be replaced.

Installation

1. The upper and lower bearing halves are not interchangeable. The upper half is drilled and grooved to provide entry of oil. Ensure bearings and surfaces are clean. Foreign material under the inserts will distort the bearings and cause failure.

2. To install the upper main bearing, place the plain end of the bearing over the shaft on the locking tang side of the block and partially install the bearing so that Main Bearing Insert Tool TOOL-6331-E or equivalent can be inserted in the oil hole in the crankshaft. With Main Bearing Insert Tool TOOL-6331-E or equivalent positioned in the oil hole in the crankshaft, rotate the crankshaft in the opposite direction of engine rotation until the bearing seats itself. Remove the tool.

3. Replace the bearing in the cap.

4. Select fit the bearing for proper clearance following procedures under Fitting Main and Connecting Rod Bearings in Section 03-00.

5. If the bearing is being replaced on journal number 1, 2 or 4, apply a light coat of engine oil XO-10W30-QSP (ESE-M2C153-E) or equivalent to the journal and bearings and install the bearing cap. Tighten the cap bolts to 81-95 Nm (60-70 lb-ft).

6. If the rear main bearing is replaced (on a work stand), clean the mating surfaces of the bearing cap and the block with Extra Strength Spot and Stain Remover B7A-19521-AA (ESR-M5B197-A) or equivalent solvent. Apply a 1.59mm (1/16 inch) bead of Silicone Rubber D6AZ-19562-B (ESB-M4G92-A and ESE-M4G195-A) or equivalent, in each corner of the rear main bearing cap saddle the full length of the saddle. Ensure the main bearing is fitted and the cap bolts tightened to 81-95 Nm (60-70 lb-ft) before installing the new crankshaft rear oil seal.

7. If the thrust bearing cap (No. 3 main bearing) has been removed, install it as follows.

8. Lubricate the journal with engine oil XO-10W30-QSP (ESE-M2C153-E) or equivalent and install the thrust bearing cap with the bolts finger-tight. Pry the crankshaft forward against the thrust surface of the upper half of the bearing. Hold the crankshaft cap to the rear. This will align the thrust surfaces of both halves of the bearing. Retain the forward pressure on the crankshaft. Tighten the cap bolts to 81-95 Nm (60-70 lb-ft).

9. Clean the oil pump inlet tube screen. Prime by filling the inlet opening with oil and rotating the pump shaft until oil emerges from the outlet opening. Install the oil pump and the inlet tube assembly.

10. Position the oil pan gasket on the cylinder block. Install the oil pan and related parts. Install the oil level dipstick.

11. Fill the crankcase. Start the engine and check for oil pressure. Operate the engine at fast idle and check for oil leaks.