Crankshaft Replacement; Oil Filter Bypass Valve Replacement; Engine Mountings - GMC G Service Manual

6A6-26 6.2L DIESEL
I f i l Tighten
• Bolts to specifications. Refer to step 4.
6. Number 3 (center) main bearing cap and bolts.
Tighten the bolts temporarily to 14 N*m (10 ft. lbs.).
[ t j | Measure
• Crankshaft endplay, as follows:
• Tap the end of the crankshaft first rear­
ward then forward with a lead hammer.
This will line up the rear main bearing and
crankshaft thrust surfaces.
• Tighten the rear main bearing cap bolts to
specifications. Refer to step 4.
• With the crankshaft forced forward, mea­
sure at the front end of the number 3 main
bearing with a feeler gage (figure 30). The
proper clearance is 0.10-0.25 mm.
7. Oil pump and oil pan, as outlined previously.
8. Glow plugs.

CRANKSHAFT REPLACEMENT

1. Remove the engine. Refer to "Engine Replacement"
in this section.
2. Refer to the 1988 Light Duty Trucks Unit Repair Man­
ual for crankshaft replacement procedures.
OIL FILTER BYPASS VALVE
REPLACEMENT
H Remove or Disconnect (Figure 31)
1. Oil filter.
2. Oil filter bypass valve. Pry out with a screwdriver.
frllH Clean
• Recess in the block.
Install or Connect (Figure 31)
1. Oil filter bypass valve. Tap into place, using a 16 mm
socket.
2. Oil filter.
3. Proper quantity and grade of engine oil. Refer to
MAINTENANCE AND LUBRICATION (SEC. 0B).

ENGINE MOUNTINGS

NOTICE: Broken or deteriorated mountings can
cause the misalignment and eventual destruc­
tion of certain drive train components. When a
single mounting breakage occurs, the remaining
mountings are subjected to abnormally high
stresses.
REMOVAL
INSTALLATION
Figure 31 — Replacing the Oil Filter Bypass Valve
INSPECTING ENGINE MOUNTINGS
Front Engine Mountings
NOTICE: When raising or supporting the engine
for any reason, do not use a jack under the oil
pan, crankshaft pulley or any sheet metal. Due
to the small clearance between the oil pan and
the oil pump screen, jacking against the oil pan
may cause it to be bent against the pump
screen, resulting in a damaged oil pickup unit.
1. Raise the engine to remove weight from the mount­
ings and to place a slight tension on the rubber cush­
ion. Observe both mountings while raising the engine.
F-02474