G 1500 1/2 Ton Van V6-4.3L VIN W (1997)
Crankshaft Main Bearing: Testing and Inspection
NOTE: When replacing rear crankshaft bearing, check for the correct part number. Some rear crankshaft bearings are 0.20 mm (0.008 inch) wider than
the standard. Identify the crankshaft by the 0.008 stamped on the rear counterweight.
Measure the necessary clearance of each crankshaft bearing to determine the proper sizes. The factory installation of the crankshaft bearings may not be
the same size for each journal.
1. Inspect the lower half of the crankshaft bearing.
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Replace both of the upper and lower half if the lower halve is worn or damaged.
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If the lower half is suitable for use, the upper half will be suitable for use.
2. Use gauging plastic in order to measure the crankshaft bearing clearance.
3. Place a piece of gauging plastic full width of crankshaft bearing onto the journal.
NOTE: Do not rotate crankshaft while gauging plastic is between the journal and the crankshaft bearing.
4. Measure all five of the bearing clearances at the same time.
5. Install the crankshaft bearing caps with arrows pointing toward the front of the cylinder block assembly.
6. Install the bearing cap bolts.
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Tighten all of the bolts to 105 Nm (77 ft. lbs.).
7. Remove the crankshaft bearing cap bolts, studs, and crankshaft bearing caps.
8. Use the provided gauging plastic in order to measure the gauging plastic at the widest point.
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If the gauging plastic shows and irregularity in the journal exceeding 0.025 mm (0.0010 inch), measure the journal with a micrometer.
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If the clearance is greater than specified select an undersized bearing.
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Re-measure the clearance.
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If the clearance cannot be brought to specifications using a standard undersize bearing, regrind the crankshaft for use with the next undersize
bearing.
