TM 5-3810-300-24&P2
corrosion protection at all times. For rust protection during the winter months an antifreeze having a corrosion preventive
should be installed in the fall. When spring arrives, drain the old antifreeze solution from the Cooling System as all
corrosion inhibitors are weakened and may be entirely exhausted, depending on how the truck has been taken care of
and how far and fast it has been driven. To rust proof the Cooling System for summer driving add a good rust inhibitor
with the first fill of clean water in the spring. This solution should then be drained in the fall and a fresh filling of
chemically treated antifreeze installed. A good quick test to determine if Cooling System needs cleaning or flushing due
to rust, scale or grease is to wipe the inside of the filler neck and header tank with the finger. If any sludge or excessive
rust and scale are present and evidenced by this test, the system needs a thorough cleaning.
Seasonal Care.
The Cooling System of any truck should be drained and flushed out at least once a year. Unless the cooling water or
antifreeze has a corrosion preventive, rust and scale will eventually clog up the Cooling System. If no recommended
cleaning solution is available when cleaning the system dissolve four pounds of washing soda in water and fill the
complete Cooling System. Leave the radiator cap off and run the engine until it is hot. Then disconnect the radiator
outlet hose so all sediment will pass through the outlet pipes. and flush thoroughly with clean water.
NOTE
REMOVE RADIATOR CAP WHEN DRAINING SYSTEM TO ASSURE PROPER DRAINING.
Cleaning.
1. Coolant shut-off cocks to heaters and other accessories should be open to allow complete circulation during cleaning,
flushing and draining. Run the engine with radiator covered if necessary until temperature is up to operating range
(160 degrees to 180 degrees F). Stop engine, remove radiator cap and drain system by opening drain cocks on
radiator and crankcase.
2. Allow engine to cool, close drain cocks and pour cleaning compound into radiator according to directions. Fill system
with water.
3. Place a clean drain pan to catch overflow, and use to maintain level in radiator. Do not spill solution on vehicle paint.
4. Replace radiator cap and run engine at moderate speed covering radiator if necessary, so that radiator core reaches a
temperature of 180 degrees F, or above, but does not reach the boiling point. Allow the engine to run at least two
hours at 180 degrees F, so that cleaning solution may take effect. Do not drive vehicle or allow liquid level in radiator
to drop low enough to interfere with circulation.
5. Stop engine as often as necessary to prevent boiling.
6. With the engine stopped, feel the radiator core with bare hands to check for cold spots, and then observe temperature
gage reading. Where there is no change in temperature for some time, drain the cleaning solution.
7. If clogging of core is relieved but not fully corrected allow the engine to cool, pressure-flush the system and repeat
cleaning operation.
4-78
