TM 5-3810-300-24&P2
8. If clogging or core, indicated by low temperature spots on core, is not relieved, radiator core must be removed for
mechanical cleaning. Mechanical cleaning requires removal of upper and lower tanks and rodding out the accumulation
rust and scale from the water passage of the core.
Pressure Flushing.
1. Disconnect the upper radiator hose which connects radiator core to engine water outlet, and remove thermostat from
engine water outlet.
2. Clamp a convenient length of hose to the radiator core outlet opening, and attach another suitable length of hose to
the radiator inlet opening to carry away the flushing stream.
3. Connect the flushing gun to compressed air and water pressure, and clamp the gun nozzle to the hose attached to the
radiator outlet opening.
4. With radiator cap on tight, fill core with water. Turn on air pressure inshort blasts to prevent core damage.
5. Continue filling radiator with water and applying air pressure as above until the water comes out clear.
6. Clamp the flushing gun nozzle firmly to a hose attached securely to the engine water outlet opening. Fill engine block
with water, partly covering water inlet opening to permit complete filling.
7. Turn on compressed air to blow out water and loose sediment. Continue filling with water and blowing out with air
until flushing stream comes out clear.
8. For badly clogged engine water jackets that do not respond to regular pressure flushing, remove engine cylinder head
and core hole plugs and with a suitable length of small copper tubing attached to the flushing gun nozzle, flush the
water jackets through openings.
9. When the vehicle is equipped with a heater connected to the Cooling System, = flush the heater, following same
procedure as for radiator core.
10. After completing the flushing operation, clean out radiator overflow pipe, inspect the water pump, clean the
thermostat and the radiator cap control valves. Check thermostat for proper operation before installation.
11. Blow insects and dirt from radiator core air passages, using water, if necessary, to soften obstructions.
INSPECTION
Radiator.
1. Top and Bottom Tank. Look for leaks, particularly where tank is soldered to core. Vibration and pulsation from
pressure can fatigue soldered seams.
2. Filler Neck. The sealing seat must be smooth and clean. Cams on filler neck must not be bent or worn so as to allow
loose fitting cap. Make sure overflow tube is not plugged.
When removing the pressure type cap from the radiator, perform the operation in two steps. Loosening the cap to its first
notch raises the valve from the gasket and releases the pressure through the overflow pipe. In the first stage position of
the cap it should be possible to depress the cap approximately 1/8-inch. The prongs on the cap can be bent to adjust this
condition. Care must be taken that the cap is not too loose as this would prevent proper sealing.
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