Crankshaft And Bearings; Crankshaft Rear Oil Seal Retainer - GMC T Series 1994 Repair Manual

■H- Install or Connect
NOTICE: Do not install thermostat assembly
without rubber O-ring. Omitting rubber O-ring
m ay result in poor engine warm-up and
reduced heater performance.
1. Thermostat (with rubber O-ring).
2. New gasket.
3. Coolant outlet.
NOTICE: Refer to "Notice" on page 6A4-1.
4. Bolts.
• Bolts to 19 N-m (14 lbs. ft.).
TORSIONAL DAMPER
Inspect
I?
Torsional damper weight for signs of shifting on the
hub. Replace as needed. Area of the torsional damper
hub shaft that contacts the front crankshaft seal for
roughness or nicks. Replace the damper if this condi­
tion exists. If damper is replaced, new balance weights
of the same size must be installed on the new damper
in the same location as the old damper.

CRANKSHAFT AND BEARINGS

IH yl Clean
• Crankshaft with solvent.
— Do not scratch the bearing journals.
— Remove all sludge from the oil passages with
compressed air.
• Main bearing inserts.
— Wipe free of oil with a soft cloth.
L*
Inspect
• Crankshaft for cracks.
— Use the magnaflux method, if available.
— Crankpins, main bearing journals, and thrust
surfaces for scoring, nicks, or damage caused
by lack of lubrication.
— Main bearing inserts for scoring or other dam­
age.
In general, the lower inserts (except the #1 bearing)
show the greatest wear and distress from fatigue. Upon
inspection, if a lower insert is suitable for reuse, it can
be assumed that the upper insert is also satisfactory. If
a lower insert shows evidence of wear or damage, both
the upper and lower inserts must be replaced.
t } | Measure (Figure 33)
Main bearing and connecting rod journal diameters
(figure 33). Refer to ''Specifications," and compare
dimensions.
Main bearing and connecting rod journals for taper
and out-of-round. Grind or replace the crankshaft if
the journals are tapered more than 0.025 mm
(0.001 inch) or out-of-round more than 0.025 mm
(0.001 inch).
Crankshaft runout.
— Mount the crankshaft in V-blocks or between
centers.
— Use a dial indicator.
— If the main journals are misaligned by more
than 0.025 mm (0.001 inch), the crankshaft is
bent and must be replaced. The main bearings
must also be replaced at the same time.
CRANKSHAFT REAR
OIL SEAL RETAINER
Disassemble
❖
Crankshaft rear oil seal if not previously removed.
Insert a screwdriver into the notches provided in
the seal retainer and pry the seal out.
Clean
All traces of old gasket from the retainer.
Inspect
L*
Retainer for cracks, porosity, and damage to the
sealing surfaces.
Important
• Install the new crankshaft rear oil seal with the
proper tool, after the retainer is assembled to the
engine, as outlined later.
A. Micrometer
V0573