TM-9-2320-387-24 HMMWV Direct Support & General Support Maintenance Manual Volume 1 Download
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TM 9-2320-387-24-l 1 l-20. COOLING SYSTEM OPERATION 1 I 1 -- The cooling system removes excess heat from the engine, engine oil, transfer oil, and transmission oil. Major components of the cooling system are: 0 A 0 B 0 C 0 D 0 E 0 F 0 G 0 H ENGINE TEMPERATURE SENDING UNIT - Sends signal indicating coolant temperature to gauge on instrument cluster. ENGINE TEMPERATURE SWITCH - Sends signal to activate control valve system to operate fan when engine temperature exceeds 220°F (104°C) and deactivates when engine temperature drops below 190°F (88°C). WATERCROSSOVER - Collects coolant from cylinder heads and channels it to the thermostat housing where it is redirected through the cooling system. THERMOSTAT - Shuts off coolant return flow to radiator until temperature reaches 190°F (88°C). Coolant is then directed to the radiator through the radiator inlet hose. RADIATOR - Directs coolant through a series of fins and baffles so outside air can dissipate excess engine heat before the coolant is recirculated through the engine. OIL COOLER - Directs engine oil (lower half of cooler), power steering oil (lower half of cooler), and transmission oil (upper half of cooler) through a series of fins or battles so outside air can remove heat from oil. SURGE TANR - Filling and expansion point for cooling system. PERSONNEL HEATER - Provides heat for personnel and interior of vehicle. - 1-26