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Sec. 6
Page 96
GM COACH MAINTENANCE MANUAL
RADIATOR, SHUTTERS, AND THERMOSTAT
TP 3381
Figure 4-Sectional View of Radiator Shutter Air Filter
condition by cleaning vane bearings thoroughly
with brush or spray gun, or both.
Use gasoline
or penetrating oil until all dirt is removed. After
shutter is once worn in, lubricating oil may be
omitted after cleaning. Frictional wear is very
slight, and excessive lubricant may increase rapid
collection of dirt. This attention is recommended
every 2000 or 5000 miles, depending upon the
nature of operation and the tendency toward dirt
collection.
AIR FILTER
Air filter, shown in (fig. 4), prevents moisture
from entering shutter thermostat.
As air from
air tank enters filter, it strikes against baffle
which diverts moisture in air stream to bottom
of housing.
Air then passes through filtering
element. Air is again filtered through felt before
entering thermostat air valves.
Periodic check
should be made for leakage at filter connections.
Tighten if necessary. With felt inserted, air filter
chamber holds slightly over one ounce of fluid.
Add fluid to filter through filler plug.
Refer
to Lubrication Chart in LUBRICATION (SEC. 13),
for intervals, quantity and type of fluid.
Larger
quantities or more frequent filling may overload
system.
Air filter should be drained at intervals shown
in Lubrication Chart by opening pet cock at bottom.
6
5
This operation should be performed with pressure
in air lines.
Every 10,000 miles, air filter should be dis-
assembled and
the felt
cleaned with cleaning
solvent or replaced.
RADIATOR SHUTTER THERMOSTAT (Fig.
5)
Thermostat valve, mounted in water line be-
tween engine head and radiator, functions auto-
matically to open and close air line to power
cylinder, which operates radiator shutter.
At periodic
intervals, thermostat
must be
cleaned by disconnecting inlet line and injecting
a cleaning fluid into thermostat. Refer to Lubri-
cation Chart in LUBRICATION (SEC.
13), for
intervals, quantity, and type of fluid. When air
line is reconnected, pressure will force fluid
through thermostat needle valve, cleaning away
any deposits of foreign matter.
Thermostat should be disassembled and cleaned
once or twice per year. Disassemble by removing
end caps and needle valve upper seat.
Wash
needle valve thoroughly in a reliable solvent. Do
not use any abrasive or metal tools in removing
deposits from needle valve or seats.
A pointed
wooden stick provides a practical method of clean-
ing tapered seats.
Care must be taken to have
all parts thoroughly cleaned before reassembling.
Felts must be renewed or thoroughly washed in
solvent.
Do not fail to clean the small felts lo-
cated in side openings.
fusert needle; then install top seat (without
spring or spacing gasket) and tighten firmly against
needle.
Use a drop or two of oil on needle to
prevent scoring. Repeat operation two or three
times until new seats, both top and bottom, have
been formed.
Remove top seat anct needle and clean thor-
oughly. fustall needle and spring, with small end
of spring seated on shoulder of needle.
Install
new spacing gasket, to provide proper needle
travel; then install top seat.
Testing (Fig. 5)
Before installation, thermostat should be tested
for proper operation.
Test can be made in a
1 Needle Valve Upper
2
Needle
3
Adjustment Wheel
4
Jacket
5 Seal Ring
6
Gasket
7
End Cap
8
Inlet
9
Felt
Seat
TP-6291
Figure 5-Sectional View of Radiator Shutter Thermostat
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