CAP
indication of the presence of rust, scale, or grease can
CLOSED
WATER
be obtained by running your finger around the inside of
CLAMP
the filler neck of the radiator. The grease and rust
AIR
deposits collected on your finger will show if this
servicing is required.
FLUSHING GUN
The use of inhibitors or rust preventives reduces
HOSE
the corrosion of metals and prevents the formation of
scale. Inhibitors are not cleaners and do not remove
rust or scale already formed. Treating the cooling
system with an inhibitor consists of adding it to the
coolant. The inhibitor should be renewed periodically,
HOSE
especially if the system has been recently cleaned or
flushed. Permanent type antifreeze contains an
inhibitor so that during cold weather a separate
inhibitor need not be used. Inhibitor in the required
amount should always be used in the cooling system
after antifreeze has been drained. The required amount
CLAMP
ASf05009
of inhibitor is indicated on the container and depends
on the cooling system capacity.
Figure 5-9.--Reverse flushing of radiator.
Using Antifreeze
WATER
HOSE
Permanent antifreeze of the ethylene glycol type is
FLUSHING GUN
used to protect the cooling system during cold weather.
Before installing antifreeze in the system, you should
CLAMP
check for leaks and, if necessary, clean and flush the
CLAMP
cooling system. Also, you should check the
OUTLET ELBOW
thermostat, pressure cap, and all hoses. If the system
THERMOSTAT REMOVED
has a radiator overflow tank, you should rinse it by
filling with water and then completely draining.
After filling the system to about one-third
capacity with water, you are ready to add the
antifreeze. But just how much antifreeze should you
use? This will depend on the capacity of the cooling
system and the lowest expected temperature. The
ASf05010
system should be protected to at least 10 below the
lowest expected temperature. Table 5-1 indicates
Figure 5-10.--Reverse flushing of water jackets.
the number of pints of permanent antifreeze needed
per gallon of cooling system capacity to afford
sending water and air through the water jackets and
protection to the various temperatures listed. Thus,
coolant passages. After flushing, the thermostat and
if your cooling system (with heater) had a capacity of
hoses can be replaced and the system refilled. Where
22 quarts (5 1/2 gallons), you would need to use
reverse-flushing equipment is unavailable, you can
approximately 18 pints (2 1/4 gallons) of antifreeze
still reverse-flush the system with an ordinary garden
to afford adequate protection to -10F or 19 1/4 pints
hose. This is often effective following the use of a
(slightly over 2 3/8 gallons) to protect to -20F. In
cleaner and neutralizer.
this connection, you should note that the maximum
protection available is obtained by using about 4 3/4
Preventing Rust
pints of ethylene glycol for each gallon of the
cooling system capacity. This means that the
Rust is the result of iron and oxygen present in the
solution would then contain about 60 percent
system, and it can only be controlled by maintaining
ethylene glycol by volume to protect to -60F. When
you attempt to use a greater proportion of antifreeze
full-strength corrosion protection at all times. An
5-10
