79
SHUTTERS
The optional radiator shutters on the TC/2000 RE assist in maintaining a constant engine temperature by
limiting the air flow through the radiator. The shutter blades are powered by air pressure from the brake
system on the vehicle. The shutters are controlled automatically by a 185
0
F Alarmstat which is located in the
upper radiator hose and an electric solenoid in the air line controlling the shutters. The shutters require no
lubrication but must be cleaned as required or at least every 2 years or 24,000 miles, whichever occurs first.
See the shutters installation diagrams provided with vendor maintenance information for plumbing, wiring
and parts requirements.
COOLING SYSTEM
CAUTION: Use extreme care when removing a radiator pressure-control cap. The sudden release of pres-
sure from a heated cooling system can result in a loss of coolant and possible personal injury (scalding)
from the hot liquid or steam.
Coolant should be drained and replaced every 2 years. See individual Quick Reference Maintenance Chart
for complete guidelines for each engine.
On vehicles used in stop-and-go service, such as the TC/2000, engine hoses deteriorate more rapidly;
therefore it is important to inspect all such hoses frequently. Hoses which are worn, chafed, hardened or
cracked must be replaced before a leak develops. On an age hardened hose, retightening a worm screw clamp
will not stop connection leaks, and further indicates that the hose needs replacement. It is also important not
to overtighten clamps as this can damage the hose, or distort the tubing connector. When replacing a hose,
the clamp should be torqued to 45 inch lbs. When checking a hose clamp, clamps should be torqued to a
minimum of 34 inch lbs.
CORSAIR EM-300 FAN CLUTCH
OPERATION
The Corsair Electromagnetic Fan Clutch is activated by 12 VDC from the vehicle electrical system. Bolted
to the front of the engine, the fan gets power from belts the usual way. A separate control functions to turn the
fan on and off as dictated by operating conditions. It operates by connecting 12 VDC to the magnets coil to
engage the clutch; breaking the 12 volt circuit to disengage the clutch.
An increase of the engine coolant temperature above a preset limit causes a normally open thermal switch
in the engine cooling system to close, “Close-on-Rise” at the present temperature.
A manual switch can also be added to the switch panel. This switch connection is parallel with the tem-
perature switch allowing you to turn the fan on anytime.
FAN CLUTCH WIRING HARNESS
Closure of the sensor switch or of the manual switch completes the 12 VDC circuit to ground. When the
circuit is completed, 12 VDC flows to the coil of the electromagnet, fixing the fan hub to the belt pulley. As
long as any switch is closed, the fan turns.
When the switch opens or power is interrupted for any reason, the coil loses power and the magnetic field
collapses, releasing the fan hub from the drive pulley. As the field collapses, polarity across the diode re-
verses, making a low-resistance circuit to ground, protecting switch contacts. If the diode fails or there is
some other break in the diode circuit, there is likely to be arcing damage in the opening switch.
Summary of Contents for TC/2000
Page 1: ...Owner s Manual TC 2000 ...
Page 3: ...2 ...
Page 106: ...105 NOTES ...
Page 111: ...Part Number 1919331 Blue Bird Corporation P O Box 937 Fort Valley GA 31030 ...