MOTOR TRUCK SERVICE MANUAL
pushing back on each side at the bottom of the top
ance and while holding in this position tighten retaining
blade. With the blades completely closed and shutter
control plunger pushed in against piston, rotate control
Full open position of shutter blades is at an angle of
lever on shaft until control rod will index with hole in
approximately 70° (not 90°).
lever. Hold lever in this position and tighten sockethead
Maximum air flow is attained when blades are open from
setscrews and clamp bolt nut. Install cotter key in control
60° to 70° (angular degrees).
Recheck linkage between shutter and control to see
Periodic inspection is advisable at which time nylon
that all slack was removed.
blade bushings should be cleaned with light or
Check to see that shutters close tightly by attempting to
penetrating oil and blown out with air pressure. DO NOT
insert a calling card between the blades. If not closed
oil at frequent intervals, only after cleaning or
tightly, repeat adjustment procedure previously outlined.
reassembly, as normal lubricating oils tend to gather dirt
Be certain shutter blades have sufficient end
and dust. Light oil on linkage periodically is desirable.
clearance (not exceed 1/16"). End clearance can be
Periodically remove thermostat piston.
adjusted by loosening bolts on side of frame that retain
Clean piston thoroughly and lubricate with # 200 fluid or
the bushing angles. Move angle to obtain adequate
1. Coolant Level Too Low.
1. Fill radiator and
check for leaks.
2. Faulty Temperature Gauge.
2. Replace gauge.
3. Slack in Linkage.
3. Adjust linkage.
4. Faulty Engine Thermostat.
4. Replace engine
Broken or Loose Fan Belt.
5 Replace or tighten
Faulty Water Pump.
6 Replace or repair
7 Clean radiator.
8 Remove shutter
control and adjust.
Incorrect Shutter Control
Thermostat Temperature Range.
10 Shutters or Linkage Binding.
10 Free shutters and
Faulty nperature Gauge
1 Replace gauge.