Prediluted 50/50 Antifreeze & Coolant.
Previously, water, alcohol, special salts and glycerin were used to produce cooling water. To date, the chemical industry has moved far ahead, and these components have been replaced by modern compounds that have improved characteristics.
As a rule, for cooling systems of modern cars antifreeze is used, the basis for which is ethylene glycol (it is used to reduce the freezing point of solutions based on water).
This mixture perfectly meets all the necessary properties of the coolant. But the lack of such a mixture is the toxicity of ethylene glycol. When it gets into the human body, the liver and kidneys are severely affected, and although only those who can not read are aware of this danger, the cases of poisoning have been fixed. From the ecological point of view, the usual discharge of spent antifreeze to the sewage system or to the ground is also dangerous. Due to the above factors manufacturers had to look for a safer alternative.
The result was the appearance of cooling liquids based on propylene glycol. Although it is completely harmless can not be called, but it is much less toxic. The disadvantage of such antifreezes is the increased viscosity at low temperature, which slightly prevents its pumping through the cooling system. But the main disadvantage of such a liquid is its high price. It is for this reason that antifreeze of this type is almost not represented on the market.
In terms of the negative effect on the cooling system parts, these two compositions are the same. As already mentioned above, to prevent the cooling fluid from affecting the metal, rubber and plastic elements add additives to it. Depending on their composition antifreeze and are divided into groups.