Temperature Sender - Toro Groundsmaster 4000-D Service Manual

Temperature Sender

The temperature sender is located near the alternator
on the water flange attached to the engine cylinder head
(Fig. 56). The resistance of the temperature sender re-
duces as the engine coolant temperature increases.
There is a gray harness wire attached to the terminal of
the switch.
Testing
1. Lower coolant level in the engine and remove the
temperature sender from water flange.
2. Suspend sender in a container of oil with a thermom-
eter and slowly heat the oil (Fig. 57).
CAUTION
Handle the hot oil with extreme care to prevent
personal injury or fire.
NOTE: Prior to taking resistance readings with a digital
multi meter, short the meter test leads together. The me-
ter will display a small resistance value (usually 0.5
ohms or less). This resistance is due to the internal re-
sistance of the meter and test leads. Subtract this value
from from the measured value of the component you are
testing.
3. Check resistance of the sender with a multimeter
(ohms setting) as the temperature increases. Replace
sender if specifications are not met.
COOLANT TEMP TEMP SENDER RESISTANCE
o o
100 F (38 C)
o o
160 F (71 C)
o o
200 F (93 C)
o o
221 F (105 C)
4. After testing is complete, install sender to the water
flange.
A. Thoroughly clean threads of water flange and
sender. Apply thread sealant to the threads of the
sender.
B. Screw sender into the water flange. Torque send-
er from 16 to 20 ft- -lb (22 to 27 N- -m).
C. Reconnect gray harness wire to sender. Apply
skin--over grease (Toro Part No. 505--165) to sender
terminal.
5. Fill engine cooling system.
Electrical System
460 ohms (approximate)
140 ohms (approximate)
54 to 78 ohms
50 ohms (approximate)
1. Temperature sender
Page 5 - - 42
1
2
Figure 56
2. Alternator
Figure 57
Groundsmaster 4000--D/4010--D