TM 5-3805-280-24-2
Engine System Operation and Tests
INSPECT THERMOSTAT AND TEST
105
28
OPENING TEMPERATURE
Visually inspect thermostat for corrosion or damage.
Replace as necessary.
Test thermostat as follows:
CAUTION: DO NOT allow thermostat or
thermometer to rest against the side or bottom
of container when heating water. Either may
rupture if overheated.
1. Remove thermostats. (See REMOVE THERMOSTATS
in Group 25.)
2. Suspend thermostat and a thermometer in a container
of water.
3. Stir the water as it heats. Observe opening action of
thermometer and compare temperatures with
specification given in chart below.
NOTE: Due to varying tolerances of different suppliers,
initial opening and full open temperatures may
vary slightly from specified temperatures.
THERMOSTAT
TEST
SPECIFICATIONS
Rating
Initial Opening (Range)
Full Open
(Nominal)
71C
(160F)
69--72C (156--162F)
84C (182F)
77C
(170F)
74--78C (166--172F)
89C (192F)
82C
(180F)
80--84C (175--182F)
94C (202F)
89C
(192F)
86--90C (187--194F)
101C (214F)
90C
(195F)
89--93C (192--199F)
103C (218F)
92C
(197F)
89--93C (193--200F)
105C (221F)
96C
(205F)
94--97C (201--207F)
100C (213F)
99C
(210F)
96--100C (205--212F)
111C (232F)
4. Remove thermostat and observe its closing action as it
cools. In ambient air the thermostat should close
completely. Closing action should be smooth and slow.
5. If any thermostat is defective on a multiple thermostat
engine, replace all thermostats.
RG,105,JW7648
1921NOV971/1
13-505
