TM-9-2320-387-10 HMMWV Operator Manual Download
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TM 9-2320-387-10 1 - 17. COOLING SYSTEM OPERATION The cooling system removes excess heat from the engine, engine oil, transfer case 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 1-16 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 control valve system when engine temperature drops below 190°F (88°C). WATER CROSSOVER - Collects coolant from cylinder heads and channels it to the thermostat housing where it is redirected through the cooling system. THERMOSTAT - Shuts flow to radiator until temperature 190°F (88°C). Coolant is directed inlet hose. RADIATOR - Directs coolant through a series of fins and bafIles 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) and transmission oil (upper half of cooler) through a series of fms or bafIles so outside air can remove heat from oil. SURGE TANK - Filling and expansion point for cooling system. PERSONNEL HEATER - Provides heat for personnel and interior of vehicle.