Why is ethylene glycol added to the water in a car radiator?

Question

chmvijay · Answer

Pure ethylene glycol has a specific heat capacity about one half that of water. So, while providing freeze protection and an increased boiling point, ethylene glycol lowers the specific heat capacity of water mixtures relative to pure water. 

    A 50/50 mix by mass has a specific heat capacity of about 3140 J/Kg C  three quarters that of pure water, thus requiring increased flow rates in same system comparisons with water. Additionally, the increase in boiling point over pure water inhibits nucleate boiling on heat transfer surfaces thus reducing heat transfer efficiency in some cases, such as gasoline engine cylinder walls. 
Therefore, pure ethylene glycol should not be used as an engine coolant in most cases.

anonymous · Answer

IT ACTS AS ANTI-FREEZE