Hydraulic System
309
HyDRAULIC FAN MOTOR
When the coolant temperature exceeds 194° F, hydraulic fluid flows through the gears of the motor, acti
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vating the fan above idle. When the coolant temperature falls below 194° F, the flow of hydraulic fluid is
diverted through a bypass passage in the fan motor, causing its operation to reduce to idle.
The hydraulic fan motor runs at varying speeds when the engine is
running. Always disconnect the battery to prevent fan motor activation
while working on the hydraulic system.
The operation of the fan motor is basically just the opposite of that of the hydraulic pump. Fluid under
pressure is released through the two pump gears of the motor. The pressure is dissipated while causing
the gears to turn the output shaft. The fan blade, which is attached to that output shaft, rotates and cools
the engine coolant flowing through the radiator core.
The fan idles at all times, even if engine coolant temperature is below
194° F. This is considered normal and is not an item for maintenance.
Fan motor control valves are preset by the manufacturer. DO NOT
attempt to adjust valve. Tampering can cause injury and possible fire due
to excess pressure causing failure of the hoses, pump, or fan motor.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...