TM 9-4940-568-10
1-22
1-16. COOLING SYSTEM.
a.
Cooling System.
The pressure-type cooling system protects the engine by removing the heat generated during combustion process.
Pressure within the cooling system is limited by a pressure release in the radiator filler cap (1). The hot coolant flows
from the engine to the radiator tank (2) and through the radiator core where a stream of air removes heat. This stream
of air is blown through the core by the fan. The water pump (3) draws coolant from the radiator and pushes it through
the engine, repeating the cooling process. Thermostat (4) mounted on the coolant outlet elbow, remains closed until
the coolant approaches 180 – 185F (82C – 85C), when it opens. When coolant temperature drops below
thermostat rating, the thermostat closes.
b.
Engine Block Heating System (Cold Operations Below 15F (–9 C)).
A coolant tank heater (5) is used to keep the engine coolant warm when the engine is shut down. It heats and
circulates the coolant within the engine. This reduces startup time and lessens engine wear caused by cold starts. It is
electrically operated and thermostatically controlled (ON at 70F (21C) and OFF at 100F (38C)). Heater operates
when connected to a 110 VAC.
5
3
4
1
2
