Fuel, Oil and Coolant Specifications
E N G I N E COOLANT
Engine coolant is considered as any solution which is
deposits, corrosion or a combination of these.
circulated through the engine to provide the means for
Chlorides, sulfates, magnesium and calcium are
heat transfer from the different engine components. In
among but not necessarily all the materials which
general, water containing various materials in solution
make up dissolved solids. Water, within the limits
is used for this purpose.
specified in Tables 1 and 2 of Fig. 1, is satisfactory as
an engine coolant when proper inhibitors are added.
The function of the coolant is basic to the design and
to the successful operation of the engine. Therefore,
coolant must be carefully selected and properly
A corrosion inhibitor is a water soluble chemical
compound which protects the metallic surfaces of the
cooling system against corrosive attack. Some of the
A suitable coolant solution must meet the following
1. Provide for adequate heat transfer.
2. Provide a corrosion resistant environment within the
3. Prevent formation of scale or sludge deposits in the
4. Be compatible with the cooling system hose and seal
5. Provide adequate freeze protection during cold
The first four requirements are satisfied by combining
a suitable water with reliable inhibitors. When
operating conditions dictate the need for freeze
protection, a solution of suitable water and a
permanent antifreeze containing adequate inhibitors
will provide a satisfactory coolant.
Any water, whether of drinking quality or not, will
produce a corrosive environment in the cooling system.
Also, scale deposits may form on the internal surfaces
of the cooling system due to the mineral content of the
water. Therefore, water selected as a coolant must be
properly treated with inhibitors to control corrosion
and scale deposition.
To determine if a particular water is suitable for use
as a coolant when properly inhibited, the following
characteristics must be considered: the concentration
solids. Chlorides and/or sulfates tend to accelerate
corrosion, while hardness (percentage of magnesium
and calcium present) causes deposits of scale. Total
Fig. 1 - Water Characteristics
dissolved solids may cause scale deposits, sludge