Radiator Additives

Antifreeze Engine Coolant and Cooling System: It contains propylene glycol, but the formulas are proprietary for each manufacturer. It is Unlikely you could make it as it requires some pretty high chemistry and quite expensive lab equipments.
The most common formulation of antifreeze is green in color and uses ethylene glycol as a base with anti corrosive additives mixed in it. The ethylene glycol part of the formula provides crucial anti freezing characteristics and the additives deliver the anti rust and anti corrosion capabilities. Beginning with 1995 models, most vehicles started coming from the factory filled with an extended life anti freeze.