TB-9-2320-335-13&P HMMWV Operator and Field Maintenance, Parts, Tools M1151A1 M1152A1 M1165A1 Download
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2-17 TB 9-2320-335-13&P ENGINE COOLING F AN DESCRIPTION OF OPERA TION When the thermostat detects the coolant is hot, the thermostat opens, and allows the coolant to be pumped to the radiator where it is routed through a series of fins and tubes. A fan draws in the outside air to help dissipate the heat before the coolant is recirculated back through the engine. The fan is driven from the engine crankshaft via the geared fan drive and a viscous drive. The geared fan drive unit is supported by the front rear crossmember, connects to the harmonic balancer of the engine and places the viscous drive and fan assembly on the same plane as, and close to, the radiator for maximum cooling efficiency. A helical gearset is utilized within the geared fan drive to change the drive angle from the crankshaft to the fan. Gear lube with friction modifier lubricates the internal components of the geared fan drive using an integral reservoir and pump. Two constant velocity joints and a torsional driveshaft connect the geared fan drive to the engine crankshaft at the harmonic balancer. (TM 9-2320-387-24-1). Flush cooling system (TM 9-2320-387-24-1). For surge tank replacement procedures, refer to TM 9-2320-387-24-1. For radiator support procedures, refer to para. 3-64.1. For oil cooler and oil cooler hose replacement procedures, refer to paras. 3-7.1 and 3-8.1. Notify DS maintenance to repair radiator (TM 9-2320-387-24-2).