1-9. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS. - Continued
The engine cooling system consists of the radiator, engine mounted water pump, temperature controlled
fan, and hoses connecting the engine and radiator, (see fig. 1-9). Hoses are installed between the transmission and the
oil cooler, built into the radiator, for cooling the transmission fluid. Additional hoses connect the engine cooling system to
the cab heater unit and to the winterization system.
To control the amount of cooling air flowing through the radiator, a compressed-air-operated radiator
shutter and fan are provided. The shutter and fan operation is automatically controlled by a multistat (temperature probe
and control valve assembly). The multistat is located in the return coolant line from the radiator to engine.
A liquid-to-liquid type auxiliary cooler is provided for additional cooling of the engine when the truck is
stationary and operating in the structural firefighting mode. The auxiliary cooler is located in the pump body and
connected with hoses to the engine cooling system. Water derived from the fire pump discharge is used for cooling the
engine coolant. The flow of water is controlled with a valve mounted on the structural control panel.
Figure 1-9. Cooling System Components