TM-9-2320-361-24-1 Field Maintenance Manual Volume 1 for M44A2 Series Trucks
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TM 9-2320-361-24-1 0003 00 0003 00-10 THEORY OF OPERATION (Contd) 0003 00-10 COOLING SYSTEM Cooling System Operation: The engine cooling system is a pressurized, thermostatically controlled system consisting of a radiator, thermostat, water pump, fan, and hoses. The major components of the cooling system are as follows: ENGINE OIL COOLER – Removes excess heat from engine oil. ENGINE TEMPERATURE SENDING UNIT – Detects temperature of engine coolant and sends an electrical signal to temperature gauge on instrument panel. THERMOSTAT – Shuts off coolant flow to radiator until temperature reaches 180°F (82°C). Coolant is then allowed to flow to the radiator through the upper radiator hose. RADIATOR FILLER CAP – When removed, filler neck serves as filling point for cooling system. When installed, cap allows cooling system to be pressurized. RADIATOR – Directs coolant through a series of fins or baffles so outside air can remove excess heat from coolant. UPPER RADIATOR HOSE – Directs coolant from engine block to radiator when thermostat opens. FAN – Pulls outside air through radiator to remove excess heat from coolant. WATER PUMP – Circulates coolant through cooling system. LOWER RADIATOR HOSE – Directs coolant from radiator back to engine block. I H G F E D C B A