C 2500 Truck 2WD V8-6.5L DSL Turbo VIN S (1997)
Crankshaft Main Bearing: Service and Repair
Installation
Bearing Selection
There are five crankshaft bearings, numbered one through five, from the front of the engine there is an arrow on the bearing cap that points toward
the front of the engine. The center, number three bearing is the thrust bearing. The upper bearing halves have an oil groove. The lower bearing
halves do not have an oil groove.
During factory assembly, the crankshaft bearings are select-fitted to each of the five crankshaft bearing bores. The proper size code is stamped on
the pan rail at the corresponding crankshaft bearing bulk head. The total diameter size range of crankshaft bearing bores one through five is
79.826-79.850 mm (3.145-3.146 inch). This range divides into three sizes, represented by the numbers 1, 2 or 3 stamped on the pan rail. The
crankshaft is color-marked in red/orange, blue or white, near the crankshaft bearing journal. Cross-referencing the number on the pan rail with the
color on the crankshaft indicates the proper bearing selection.
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Crankshaft bearings are available in standard 0.013 mm (0.0005 inch) and 0.026 mm (0.0010 inch) undersizes for select fitting, in order
to attain proper crankshaft bearing clearance.
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Undersize refers to the crankshaft diameter.
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For service purposes, bearing size combinations provide the following clearances:
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Crankshaft bearing numbers 1, 2, 3 and 4: 0.045-0.083 mm (0.0018-0.0033 inch).
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Crankshaft bearing number 5: 0.055-0.093 mm (0.0022-0.0037 inch).
NOTE: The upper crankshaft bearings must have the holes for the piston oil nozzles.
1. Install the upper crankshaft bearing inserts to the block.
2. Install the lower crankshaft bearing inserts to the crankshaft bearing caps.
3. Apply engine oil to the crankshaft bearings.
CAUTION: The crankshaft bearing caps are to be tapped into place with a brass or leather mallet before the attaching bolts are installed. Do not
use the attaching bolts to pull the crankshaft bearing caps into their seats, as this may damage the bearing cap and/or block.
