Figure 1-8. Engine Cooling System

ARMY TM 9-6115-464-12 AIR FORCE TO 35C2-3-445-1 NAVY NAVFAC P-8-624-12 1-16 ENGINE COOLING SYSTEM. The engine cooling system (Figure 1–8) consists of a radiator, hoses, ther- mostat, water pump, a belt driven fan, cooling jacket and oil cooler. The water pump forces coolant through pas- sages (cooling jackets) in the engine block and cylinder head where the coolant absorbs heat from the engine. When the engine reaches normal operating temperature, the thermostat opens and the heated coolant flows through the upper radiator hose assembly into the radiator tubes. The cooling fan circulates air through the radia- tor where the coolant temperature is reduced. The coolant high temperature indicator is an indicator lamp with a red lens. It illuminates when the coolant temperature rises above 217± 3°F and the high coolant temperature protective device actuates. The coolant temperature gauge is a dial indicator type gauge which is calibrated in degrees Fahrenheit from 120 to 240. Normal operation indication is 170°F (76.7°C) to 200°F (93.3°C). Figure 1-8. Engine Cooling System 1-18