As a heat transfer medium, water is very efficient. However, water alone poses limitations such as the freezing and boiling points, corrosion resistance, rust prevention, and compatibility with seals and gaskets. To overcome these weaknesses and enhance the efficacy of coolant systems, specifically designed additives to combat corrosion, rust, and build-up of deposits are incorporated into coolant formulations. These additives, when combined with the water and glycol mixture, serve a multitude of functions, notably lowering the freezing point and elevating the boiling point, forming protective barriers, shielding vulnerable surfaces from the corrosive effects of coolant in the coolant mixture.

Color of a coolant or an anti-freeze fluid does not ensure any performance standard. They are dyed with colors to avoid accidents.