the solvent to the radiator core. Use air to remove the
The temperature of the coolant circulating through the
remaining dirt. Repeat this process as many times as
engine is lowered by the action of the radiator and the
necessary, then rinse the radiator with clean water and
fan. The radiator is mounted in front of the engine so
dry it with air.
that the fan will draw air through it, thereby lowering and
maintaining the coolant temperature to the degree
necessary for efficient engine operation.
Provide adequate ventilation of the
The life of the radiator will be considerably prolonged if
working area to avoid possible toxic
the coolant used is limited to either clean, soft water and
effects of the cleaning spray.
a corrosion inhibitor or a mixture of water and a
Another method of cleaning the radiator is the use of
use of any other type antifreeze is not recommended.
steam or a steam cleaning device, if available. If the
foreign deposits are hardened, it may be necessary to
To increase the cooling efficiency of the radiator, a
metal shroud is placed around the fan. The fan shroud
must be fitted airtight against the radiator to prevent
The scale deposit inside the radiator is a result of using
recirculation of the hot air drawn through the radiator.
hard, high mineral content water in the cooling system.
Hot air which is permitted to pass around the sides or
The effect of heat on the minerals in the water causes
bottom of the radiator and is again drawn through the
the formation of scale, or hard coating, on metal
radiator will cause overheating of the engine.
surfaces within the radiator, thereby reducing the
transfer of heat. Some hard water, instead of forming
Another cause of overheating is slippage of the fan
scale, will produce a silt-like deposit which restricts the
drive belts which is caused by incorrect belt tension,
flow of water. This must be flushed out at least twice a
worn belts or worn fan belt pulley grooves, or the use of
year--more often if necessary (see Chapter 6).
fan belts of unequal length when two or more belts are
used. The belt tension and condition of the belts should
A drain is provided at the bottom of the oil cooler
be checked periodically as outlined on Page 10-11-3.
A radiator that has a dirty, obstructed core or is leaking,
To remove the hardened scale, a direct chemical action
a leak in the cooling system, or an inoperative
A flushing compound such as
thermostat will also cause the engine to overheat. The
salammoniac, at the specified rate of 1/4 pound per
radiator must be cleaned, the leaks eliminated, and
each gallon of radiator capacity, should be added to the
defective thermostats replaced immediately to prevent
coolant water in the form of a dissolved solution while
serious damage from overheating.
the engine is running. Operate the engine for at least 15
minutes, then drain and flush the system with clean
The external cleanliness of the radiator should be
checked if the engine overheats and no other causes
Other flushing compounds are commercially available
and should be procured from a reliable source. Most
compounds attack metals and should not remain in the
engine for more than a few minutes. A neutralizer
The radiator should be cleaned whenever the foreign
should be used in the cooling system immediately after
deposits are sufficient to hinder the flow of air or the
a descaling solvent is used.
transfer of heat to the air. In a hot, dusty area, periodic
cleaning of the radiator will prevent a decrease in
For extremely hard, stubborn coatings, such as lime
efficiency and add life to the engine.
scale, it may be necessary to use a stronger solution.
The corrosive action of a stronger solution will affect the
The fan shroud and grill should be removed, if possible,
thin metals of the radiator, thereby reducing its
to facilitate cleaning of the radiator core.
operating life. A complete flushing and rinsing is
mandatory and must be accomplished skillfully.
An air hose with a suitable nozzle is often sufficient to
remove loose dust from the radiator core. Occasionally,
After the solvent and neutralizer have been used and
however, oil may be present requiring the use of a
the cooling system is flushed, completely drain the
solvent, such as mineral spirits, to loosen the dirt. The
entire system again and fill it with clean, soft water
use of kerosene, or fuel oil is NOT recommended as a
solvent. A spray gun is an effective means of applying