Chapter 8 - Caterpillar Engine and Related Systems
240
• Coolant returns to the engine through the hose
that connects to bottom of the water pump.
See Figure 8.56.
• A temperature sender on the water pump com-
pletes a ground circuit to trigger the over-temp
light when the coolant temperature exceeds 230
deg.f. (110 deg.c.). See Figure 8.57.
NOTE: Because water transmits temperature
changes more effectively than air, the over-temp
light may not illuminate if the engine is over-
heating AND low on coolant.
NOTE: Refer to the Electrical chapter for more
detailed information.
• The fan switch is mounted on the bottom front
edge of the radiator, next to the return hose con-
nection. See Figure 8.58.
NOTE: In this location, the fan switch monitors
the temperature of the coolant as it exits the
radiator. If the exit temperature of the coolant is
not low enough, the fan turns-on to pass more
air through the radiator.
• A 1 U.S. Qt. (.95 L.) reservoir is mounted next to
the radiator. The pressure cap on the filler neck
of the radiator allows coolant to enter the reser-
voir as it gets hot and expands. Coolant is
drawn back into the radiator as it cools and con-
tracts. See Figure 8.59.
Figure 8.56
To-radiator
Return
Figure 8.57
Temperature
sender
Figure 8.58
Front / bottom
edge of radiator
Fan
switch
Return hose
Figure 8.59
Over-flow tube
Reservoir
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