TM 5-3820-245-14&P
COOLING SYSTEM
The cooling system used on a Series 53 engine is a radiator and fan. A centrifugal-type water pump is used to circulate
the engine coolant in each system. Each system incorporates thermostats to maintain a normal operating temperature of
160-185F (71-85C). Typical engine cooling systems are shown in Fig. 18.
Radiator Cooling System
The engine coolant is drawn from the bottom of the radiator core by the water pump and is forced through the oil cooler
and into the cylinder block. The coolant circulates up through the cylinder block into the cylinder head, then to the water
manifold and thermostat housing. From the thermostat housing, the coolant returns to the radiator where it passes down a
series of tubes and is cooled by the air stream created by the fan.
When starting a cold engine or when the coolant is below operating temperature, the coolant is restricted at the thermostat
housing(s) and a bypass provides water circulation within the engine during the warm-up period.
Figure 7-13. Typical Cooling System for In-Line Engines
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