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Groundsmaster 4100--DPage 5 -- 28Electrical System
Temperature Sender
The temperature sender is located near the alternator
on the water flange attachedtothe engine cylinder head
(Fig. 41). The resistance of the temperature s ender 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. 42).
CAUTION
Handle the hot oil with extreme care to prevent
personal injury or f ire.
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 thecomponentyouare
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
100
o
F(38
o
C) 460 ohms (approximate)
160
o
F(71
o
C) 140 ohms (approximate)
200
o
F(93
o
C) 54 to 78 ohms
221
o
F (105
o
C) 50 ohms (approximate)
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.
Figure 41
1. Temperature sender 2. Alternator
1
2
Figure 42