TM 5-4320-300-14
Table 4-2. Organizational Maintenance Troubleshooting - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
WARNING
Do not remove thermostat when engine is at operating
temperature unless it is absolutely necessary. Hot coolant
escaping from the cooling system can cause severe
scalding. If thermostat must be removed, open the radiator
cap part way and wait until escaping air stops. Then drain
cooling system to a level below the thermostat.
a.
Remove and test the thermostat. Remove radiator cap
and open draincock at bottom right of radiator.
Drain the cooling
system to a level where the coolant is below the thermostat.
Disconnect the radiator hose at water outlet elbow after loosening
clamp. Remove bolts, lockwashers, water outlet elbow, gasket,
and thermostat. Check the operation of the thermostat by
immersing it in a container of hot water. Place a thermometer in
the container, but do not allow it to touch the bottom. Agitate the
water to maintain an even tem- perature throughout the
container. As the water is heated, the thermostat should begin to
open when the temperature reaches 167-172°F (75-780C). The
opening temperature is stamped on the thermostat. The
thermostat should be fully open at approximately 190-192°F (88-
89° C).
If thermostat is faulty, re- place it. Remove any old gasket from
gasket surface of thermostat housing and the water outlet elbow.
Install new gasket and position water outlet elbow. Install
mounting bolts and lockwashers. Tighten bolts to 23-26 ft-lbs
(31-35 N.m). Position upper radiator hose
4-41
