ARMY TM 9-6115-641-24
AIR FORCE TO 35C2-3-456-12
2-93-1.
a.
b.
c.
d.
2-93-2.
a.
b.
c.
d.
2-93-3.
a.
b.
c.
d.
e.
f.
g.
h.
Shut down generator set.
Allow coolant system to cool down before performing maintenance. Hot fluids
or steam can cause bums to skin. Failure to observe this warning could result in
severe personal injury.
Open left side engine access door and disconnect negative battery cable.
Tag and disconnect coolant high temperature switch (5, Figure 2-25) electrical leads.
Unscrew coolant high temperature switch (5) from thermostat housing.
Remove coolant high temperature switch, paragraph 2-93-1.
Use clean, low pressure air, 30 psi maximum. Wear protective glasses when using
compressed air. Failure to follow these instructions could result in eye injury.
Dry cleaning solvent is flammable and toxic to eyes, skin, and respiratory tract.
Skin/eye protection required. Avoid repeated/prolonged contact. Good general
ventilation is normally adequate.
Clean coolant high temperature switch with filtered compressed air and cleaning cloth (Item 6, Appendix C)
lightly moistened with dry cleaning solvent (Item 18, Appendix C).
Inspect coolant high temperature switch for cracked casing, corrosion, stripped or damaged threads, and bent
or broken connector pins.
Install coolant high temperature switch, paragraph 2-93-4.
Testing.
Remove coolant high temperature switch, paragraph 2-93-1.
Suspend coolant high temperature switch in container of clean 50/50 mixture of antifreeze and water so that
sensing element is completely immersed but not touching sides or bottom of container.
Suspend reliable thermometer in container. Do not allow end of thermometer to rest on container bottom.
Set multimeter for ohms and connect between high temperature switch terminals. Multimeter should indicate
open circuit.
Gradually heat antifreeze/water mixture so that heat will be evenly distributed and observe thermometer and
multimeter.
At 220 to 230°F (105 to 110°C), multimeter should indicate continuity.
Replace coolant high temperature switch if it fails to operate as above.
Install coolant high temperature switch, paragraph 2-93-4.
2-129
2-93. COOLANT HIGH TEMPERATURE SWITCH.
Removal.
Cleaning and Inspection.
