pump should be removed and the radiator and engine
Leave all of the drain cocks open until refilling the
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
the same coolant used in the engine. Whenever the
cooling system in a direction opposite to the normal flow
engine cooling system is drained, each exhaust
of coolant, loosening and forcing scale deposits out.
manifold drain cock, located on the bottom near the
exhaust outlet, must be opened.
The radiator is reverse-flushed as follows:
Raw water pumps are drained by loosening the cover
1. Remove the radiator inlet and outlet hoses and
attaching screws. It may be necessary to tap the raw
replace the radiator cap.
water pump cover gently to loosen it. After the water
2. Attach a hose at the top of the radiator to lead water
has been removed, tighten the screws.
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
The cooling system should be flushed each spring and
and the air hose to the compressed air outlet.
fall. The flushing operation cleans the system of
5. Turn on the water and, when the radiator is full, turn
antifreeze solution in the spring and removes the
on the air in short blasts, allowing the radiator to fill
summer rust inhibitor in the fall, preparing the cooling
between air blasts.
system for a new solution. The flushing operation
should be performed as follows:
CAUTION: Apply air gradually. Do not exert
1. Drain the previous season's solution from the engine.
more than 30 psi air pressure. Too great a
2. Refill the cooling system with soft clean water. If the
pressure may rupture a radiator tube.
engine is hot, fill slowly to prevent rapid cooling and
distortion of the engine castings.
6. Continue flushing until only clean water is expelled
3. Start the engine and operate it for 15 minutes to
from the radiator.
circulate the water thoroughly.
4. Drain the cooling system completely.
The cylinder block and cylinder head water passages
5. Refill the system with the solution required for the
are reverse-flushed as follows:
1. Remove the thermostat and the water pump.
Cooling System Cleaners
2. Attach a hose to the water inlet of the cylinder block
to drain the water away from the engine.
If the engine overheats and the fan belt tension and
3. Attach a hose to the water outlet at the top of the
water level are satisfactory, clean and flush the entire
cylinder block and insert the flushing gun in the hose.
cooling system. Remove scale formation by using a
4. Turn on the water and, when the water jackets are
quality de-scaling solvent. Immediately after using the
filled, turn on the air in short blasts, allowing the engine
solvent, neutralize the system with the neutralizer. It is
to fill with water between air blasts.
important that the directions printed on the container of
5. Continue flushing until the water from the engine
the de-scaling solvent be thoroughly read and followed.
After the solvent and neutralizer have been used,
If scale deposits in the radiator cannot be removed by
completely drain the engine and radiator and reverse-
chemical cleaners or reverse-flushing as outlined above,
flush before filling the cooling system.
it may be necessary to remove the upper tank and rod
out the individual radiator tubes with flat steel rods.
Circulate water through the radiator core from the
bottom to the top during this operation.
After the engine and radiator have been thoroughly
cleaned, they should be reverse-flushed. The water