Fuel Oil and Coolant Specifications
Engine coolant is considered as any solution which is circulated through the engine to provide the means for heat transfer
from the different engine components. In general, water containing various materials in solution is used for this purpose.
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 maintained.
A suitable coolant solution must meet the following basic requirements:
1. Provide for adequate heat transfer.
2. Provide a corrosion resistant environment within the cooling system.
3. Prevent formation of scale or sludge deposits in the cooling system.
4. Be compatible with the cooling system hose and seal materials.
5. Provide adequate freeze protection during cold weather operation. 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 of chlorides, sulfates, total hardness and dissolved solids. Chlorides and/or sulfates
tend to accelerate corrosion, while hardness (percentage of magnesium and calcium present) causes deposits of scale.
Total dissolved solids may cause scale deposits, sludge deposits, corrosion or a combination of these. Chlorides,
sulfates, magnesium and calcium are among but not necessarily all the materials which make up dissolved solids.
Water, within the limits specified in Tables I and 2 of Fig. 1, is satisfactory as an engine coolant when proper inhibitors
A corrosion inhibitor is a water soluble chemical compound which protects the metallic surfaces of the cooling system
against corrosive attack. Some of the
Fig. 1 - Water Characteristics