TM 5-3820-245-14&P
Cooling System Cleaners
If the engine overheats and the fan belt tension and water level are satisfactory, clean and flush the entire cooling system.
Remove scale formation by using a quality descaling solvent. Immediately after using the solvent, neutralize the system
with the neutralizer. It is important that the directions printed on the container of the descaling solvent be thoroughly read
and followed.
After the solvent and neutralizer have been used, completely drain the engine and radiator and reverse flush before filling
the cooling system.
Reverse Flushing
After the engine and radiator have been thoroughly cleaned, they should be reverse flushed. The water pump should be
removed and the radiator and engine reverse flushed separately to prevent dirt and scale deposits clogging the radiator
tubes or being forced through the pump. Reverse flushing is accomplished by hot water, under air pressure, being forced
through the cooling system in a direction opposite to the normal flow of coolant, loosening and forcing scale deposits out.
The radiator is reverse flushed as follows:
1. Remove the radiator inlet and outlet hoses and replace the radiator cap.
2. Attach a hose at the top of the radiator to lead water away from the engine.
3. Attach a hose to the bottom of the radiator and insert a flushing gun in the hose.
4. Connect the water hose of the gun to the water outlet and the air hose to the compressed air outlet.
5. Turn on the water and, when the radiator is full, turn on the air in short blasts, allowing the radiator to fill between
air blasts.
NOTE
Apply air gradually. Do not exert more than 30 psi (207 kPa) air pressure. Too great a pressure
may rupture a radiator tube.
6. Continue flushing until only clean water is expelled from the radiator.
The cylinder block and cylinder head water passages are reverse flushed as follows:
1. Remove the thermostat and the water pump.
2. Attach a hose to the water inlet of the cylinder block to drain the water away from the engine.
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