Temperature Sender - Toro Groundsmaster 4700-D Service Manual

Temperature Sender

The temperature sender is located near the alternator
on the water flange attached to the engine cylinder head
(Fig. 44). There is a gray wire attached to the terminal
of the sender.
The resistance of the temperature sender reduces as
the engine coolant temperature increases. The chang-
ing resistance of the temperature sender signals the
console temperature gauge to indicate engine coolant
temperature during machine operation.
Temperature Sender Test
1. Park machine on a level surface, lower cutting
decks, stop engine, apply parking brake and remove
key from ignition switch. Open hood to gain access to
engine.
CAUTION
Make sure engine is cool before removing the
temperature sender from engine.
2. Lower coolant level in the engine and remove the
temperature sender from water flange.
3. Put sender in a container of oil with a thermometer
and slowly heat the oil (Fig. 45).
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.
4. Check resistance of the sender with a multimeter
(ohms setting) as the temperature increases. Replace
sender if specifications are not met.
Groundsmaster 4500--D/4700--D
OIL TEMP
o o
100 F (38 C)
o o
160 F (71 C)
o o
200 F (93 C)
o o
221 F (105 C)
5. Install sender to the water flange.
A. Clean threads of water flange and sender thor-
oughly. 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 (21.7 to 27.1 N- -m).
C. Connect gray wire to sender. Apply skin--over
grease (Toro Part No. 505--47) to sender terminal.
6. Fill engine cooling system.
1. Temperature sender
Page 5 - - 31
TEMP SENDER RESISTANCE
460 ohms (approximate)
140 ohms (approximate)
54 to 78 ohms
50 ohms (approximate)
1
2
Figure 44
2. Alternator
Figure 45
Electrical System