Operation and maintenance manual

Section 210-0010
1
SM 2116 1-02
COOLING SYSTEM - Cooling Fan and Motor
SM - 2662
1 - Radiator
2 - Fan
3 - Fan Motor
4 - Fan Hub Adaptor
Fig. 1 - Exploded View Of Hydraulic Fan Drive
DESCRIPTION AND OPERATION
Numbers in parentheses refer to Fig. 1.
Note: The rate of fan speed change and maximum
fan speed is preset to the cooling needs of the engine.
The hydraulic fan drive system uses an electrical
signal from the engine electronic control module
(ECM) to provide the appropriate fan speed
necessary to satisfy any cooling demand. The fan (2)
is driven by a single vane type hydraulic motor (3),
which is supplied by a dedicated engine cooling
section of the triple gear pump. The fan motor (3) can
also be supplied by the brake section of the triple gear
pump when accumulators are charged. Refer to
Section 250-0040, TRIPLE PUMP, and Section 250-
0000, BRAKING SYSTEM SCHEMATIC.
After the accumulators are charged, oil from the brake
section of the triple pump will be forced to the fan
motor (3), causing the fan (2) to rotate. At pre-
determined conditions, an electrical signal closes the
low temperature unloader valve. The oil from the
engine cooling section of the triple pump is then
directed to the fan motor (3), increasing oil flow
through fan motor (3). Hence fan speed is increased
until the fan (2) is fully engaged. Refer to Section 210-
0045, LOW TEMPERATURE UNLOADER VALVE.
When electrical signal reopens the low temperature
unloader valve, oil from engine cooling section of
1
9
10
11
7
8
5
4
2
3
6
9 - Split Pin
10 - Slotted Nut
11 - Washer
5 - Motor Carrier Frame
6 - Fan Guard
7 - Bolt
8 - Lockwasher