1938 Cadillac V16 - GM Heritage Center

Cooling System
The attention required by the cooling system consists of
keeping it filled to the proper level with the proper fluid, and
keeping all connections tight to insure a leak-proof system.
The capacity of the cooling system is 30 quarts when
filled to the proper level, which is one inch below the top of
the upper tank.
Anti-Rust Treatment—When the car is delivered to
the owner, a small amount of chemical inhibitor is added to
the fluid in the cooling system, in order to reduce foaming
and retard the formation of rust and scale, thus helping to
keep the system clean. It is not necessary to add more inhibitor
each time that water or anti-freeze is added, but
whenever the cooling system is drained and refilled, a suitable
inhibitor should be added. Your Authorized Service
Station can advise you regarding the proper material to use.
Cleaning Cooling System—It is recommended that the
cooling system be thoroughly cleaned and flushed twice a
year, or every 6,000 miles, preferably by reverse-flow flushing.
In any event, the cooling system should be cleaned and thoroughly
tightened before anti-freeze is added at the beginning
of cold weather.
The following method of cleaning the cooling system can
be used if facilities for reverse-flow flushing are not convenient.
Run the engine until it is warm; then stop the engine and
open the three drain valves for the cooling system. One
drain valve is located at the bottom of each cylinder group
and one at the lower left hand corner of the radiator. All three
valves must be open to drain the engine completely. After
the liquid has drained off, refill the cooling system with hot
water, run the engine for a few minutes and again drain the
system. Repeat this operation until the water is clean when
it is drained.
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In cases where the accumulation of rust and scale is so
great that this method does not clean the system adequately,
the system should be flushed out, using a solution of water
containing one pint of sal-soda (washing soda) and one quart
of kerosene, and running the engine for half an hour. After
this operation, the system must again be thoroughly flushed
in order to clean out all traces of this cleaning solution. Do
not allow any of the solution to reach the car finish.
Anti'Freeze
Anti-freeze solutions that can be safely used are of two
types: The volatile types such as denatured alcohol and
methanol or the non-volatile types such as distilled glycerine
and ethylene glycol (Prestone).
If you prefer to use alcohol or methanol solutions, it is
important that the solution be tested at frequent intervals,
and that sufficient anti-freeze be added to replace any lost
by evaporation; otherwise there is a danger of damage by
freezing. When using these solutions, it is also important
to avoid spilling any on the car finish, or if any is spilled, to
flush off immediately with a large quantity of water.
Distilled glycerine and ethylene glycol are more expensive
in first cost but, as they are not lost by evaporation, only
water needs to be added. Solution lost through leaking or
foaming must, of course, be replaced and on this account it
is especially important to make sure that the system is leakproof
before adding this type of anti-freeze.
Glycerine and ethylene glycol should be used in accordance
with instructions and in the proportions recommended
by the anti-freeze manufacturer. Ordinarily they should not
be mixed with other solutions. No additional rust inhibitor
should be added when the anti-freeze contains an inhibitor.
Many branded alcohol anti-freezes and most non-volatile
anti-freezes contain rust inhibitors.
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