34
TK 56433-5-MM-EN
N
No
otte
e:: If an engine runs with air trapped in the block,
the engine may be damaged. The high water
temperature switch may not protect an engine
that has air trapped in the block, because the
high water temperature switch is designed to
protect an engine from overheating due to
failures in the cooling system.
1.
Remove the plug from the front end of the water
pump below the thermostat housing as shown
(
2.
Slowly pour the coolant into the system until you
see coolant at the plug fitting.
3.
Reinstall the plug.
4.
Pour coolant into the system until it appears to be
full.
Figure 13.
Remove Plug from Water Pump
1.
Plug
5.
Verify that the amount of coolant that goes back
into the system is approximately equal to the
amount of coolant that came out of the system.
6.
Start the engine and monitor the coolant
temperature with the unit engine coolant
temperature gauge, or by using a non-contact
thermometer pointed at the thermostat housing in
the location of the high water temperature switch or
sensor.
a.
When the temperature reaches 150 F (66 C),
shut the engine off for two minutes.
N
No
otte
e:: This allows time for the thermostat to
heat soak and open fully, ensuring that
any remaining air will be purged out of
the engine block when the engine is
restarted.
7.
Restart the engine and run it in low speed.
a.
Remove the cap from the expansion tank and
slowly pour coolant into expansion tank until it
is full, then reinstall the expansion tank cap.
8.
Repeat steps 6 and 7 until the coolant level
stabilizes.
Engine Thermostat
For the best engine operation, use a 160 F (71 C)
thermostat year-round.
Coolant Level Switch
The expansion tank uses a reed type coolant level
switch. The coolant level switch senses the position of
the magnetic float inside the expansion tank. When the
coolant level is above the switch, the float is in the
upper position and the switch is closed. When the
coolant level is below the switch, the float is in the
lower position and the switch is open.
Figure 14.
Expansion Tank
1.
Coolant Level Switch
Testing the Coolant Level Switch
Testing the switch in the unit is accomplished by
adjusting the coolant level and also by removing the
expansion tank from the unit by flipping the tank
upside down and right side up.
1.
Remove the wire harness connector from the
coolant level switch.
2.
Use an ohmmeter to check the continuity of the
switch at the connection pins.
3.
Verify the coolant level is above the switch and
check the continuity of the switch. The switch
should be closed. If the tank was removed from the
unit, accomplish this check with the tank upside
down.
4.
Drain coolant from the expansion tank until the
coolant level is well below the switch level and
check continuity of the switch. The switch should be
open. If the tank was removed from the unit,
