Crankshaft & Main Bearings
WARNING: This page does not describe the selected car, but rather 55 other vehicles, including the 1999 Oldsmobile Bravada, 1999 GMC Yukon, 1999 GMC Suburban, 1999 GMC Sonoma, and 1999 GMC Sierra. However, it is still accessible from the selected car via links, so may be relevant.
- Mark bearing caps for reassembly. Measure journal diameter, out-of-round, taper and oil clearance. If measurement is not within specification, replace main bearings and/or machine crankshaft. See appropriate CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS. Align thrust bearing surfaces, and measure crankshaft end play. See THRUST BEARING . Main bearing caps are press fit.
- Using Tool (J-6125-B and J-41348), carefully remove caps for service. Install main bearings and main caps. Tap bearing caps into cylinder block cavity using a brass, lead, or leather mallet before installing attaching bolts. DO NOT use cap bolts to pull crankshaft bearing caps into seats. Tighten NEW main cap bolts evenly. On 5.7L engine, crankshaft can be ground to.0090" (.229 mm) undersize. Undersize bearings are available. Install crankshaft bearing caps with arrows facing front of engine.
CAUTION:
On some 4.3L, 5.0L and 5.7L engines, the distance between rear main bearing thrust faces is.008" (.2 mm) wider than standard (identified by.008" stamped on crankshaft rear counterweight). When replacing rear main bearings on these engines, use only.008" (.2 mm) wider bearings.