G643 (E) Service Manual Chapter 3. Engine Mechanical System
82
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.
Figure 12-44 Crankshaft Sprocket Replacement
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).
