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 REFERENCE INFORMATION 0 11 . . ENGINE COOLING I SURGE COOLANT TANK FILLER SURGE I CAP TANK WARNING Do not remove surge tank filler cap before releasing internal pressure when engine temperature is above IW’F (WC). Steam or hot coolant under pressure will cause injury. Check seal and spring on pressure cap. Replace pressure cap (para. 361). - i Flush cooling system (para. 3-61). For surge tank and radiator support replacement procedures, refer to paras. 3-64 and 3-65. For oil cooler and oil cooler hose replacement procedures, refer to paras. 3-7 and 3-6. Notify DS maintenance to repair radiator (chapter 17). - : ENGINE COOLING FAN DESCRIPTION OF OPERATION An external line from the power steering gear brings hydraulic fluid to the clutch fan solenoid through i control valve (normally open) and then to the fan drive. keeping it disengaged. The action of the valve is controlled by the time-delay module and the fan temperature switch. During normal operation, the fan timer switch is closed. This keeps the control valve in the open position and the drive disengaged. As the engine reaches a temperature of about 215°F (102%). the temperature switch opens and the control valve closes. This engages the fan. If the fan is engaged and the accelerator is floored, the throttle position sensor disengages the fan drive for a period of 20 seconds. The easiest way to determine if the fan is engaged is to stand outside the drivers door and gently work the accelerator. If the fan is engaged, you will feel a breeze from the engine area. If the fan is not engaged, you won’t feel the breeze. 2-163