A . Coat a new camshaft plug with sealer GM P/N 12345493 or equivalent. B . Install the plug. The plug must be installed deep enough in camshaft bore. Balance Shaft Inspect • Balance shaft front roller bearing and rear sleeve for damage or excessive wear. The bearings are serviced as an assembly. Use the correct tools for properly servicing the bearings. • Balance drive and driven gears for nicks or burrs. Replace gears that are damaged. • Front and rear bearing journal diameters. Replace the balance shaft if the diameter exceeds the specifications. Refer to “Specifications”. • Rear sleeve bearing journal clearance. Replace the balance shaft if the clearance exceeds the specification.
Refer to “Specifications”. Timing Chain and Sprockets Inspect • Sprockets for chipped teeth and wear. • Timing chain for damage. • It should be noted that excessively worn sprockets will rapidly wear a new chain. Likewise, an excessively worn chain will rapidly wear a new set of sprockets. Crankshaft Sprocket Replacement Figure 12-44 Tools Required: J 5825-A Crankshaft Sprocket Puller J 5590 Crankshaft Sprocket Installer Remove of Disconnect 1 . Crankshaft Sprocket. Use J 5825-A (figure 12-44). 2 . Key, if necessary. Install or Connect 1 . Key, if necessary. 2 . Crankshaft sprocket. Use J 5590 (figure 12-44). Figure 12-44 Crankshaft Sprocket Replacement G643 (E) Service Manual Chapter 3.
Engine Mechanical System 82