TM 9-2320-269-20-1
COOLING SYSTEM - CONTINUED
SURGE TANK
The surge tank is a welded box unit that serves as a coolant reservoir and allows for expansion of coolant when hot. It has
a sight glass for checking the level of coolant in the system. Coolant is added to the system through the surge tank.
HOSES AND LINES
Five flexible hoses carry coolant between components of the system: the radiator inlet hose from the thermostat housing,
a radiator inlet/outlet hose to the surge tank, a radiator outlet hose to the water pump manifold, air compressor outlet hose
to the surge tank, and a water pump inlet hose from the surge tank. Five metal lines carry coolant flow through the engine:
the air compressor inlet line from the thermostat housing, an air compressor to water manifold line, an oil cooler to cylinder
head line, and two cylinder head to cylinder block lines.
WATER PUMP
coolant from the radiator and pumps it through the engine for cooling.
FAN
The fan is a modulated unit mounted on the water pump shaft and is belt-driven by the engine crankshaft. It draws air
through the radiator to allow cooling when the vehicle is not moving fast enough to force a sufficient amount of air through
the radiator.
THERMOSTATS
There are two wax core and spring-type thermostats mounted in a housing on top of the cylinder block. They block the flow
of coolant to the engine when cold, causing the coolant to bypass directly back into the radiator. As engine temperature
increases, the wax core expands against the spring allowing coolant to flow into the engine.
OIL COOLER
The oil cooler is a hollow construction with a center coil mounted on the left side of the cylinder block. It allows coolant to
circulate around oil pumped through the center coil to absorb heat from the oil.
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