TB-9-2320-335-13&P HMMWV Operator and Field Maintenance, Parts, Tools M1151A1 M1152A1 M1165A1 Download

Page 16 of 680

TB 9-2320-335-13&P 1-6 1-20.1. COOLING SYSTEM OPERATION (SERIAL NUMBERS 300000 AND ABOVE) The cooling system removes excess heat from the engine, engine oil, transfer case oil, and transmission oil. Major components of the cooling system are: B ENGINE TEMPERATURE SENDING UNIT – Sends signal indicating coolant temperature to gauge on instrument cluster. A TRANSFER CASE – Directs engine coolant through a series of fins or baffles so coolant can remove heat from transfer case oil. D 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. C WATER CROSSOVER – Collects coolant from cylinder heads and channels it to the thermostat housing where it is redirected through the cooling system. E 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. F G H OIL COOLER – Directs engine oil (lower half of cooler) and transmission oil (upper half of cooler) through a series of fins or baffles so outside air can remove heat from oil. SURGE TANK – Filling and expansion point for cooling system. DIFFERENTIAL COOLER – Directs engine coolant through a series of fins or baffles so coolant can remove heat from differential oil. A H B C D E F G