Anti Freeze is what it's called. It prevents freezing and also has anti rust and lubricant in it.

You'll find lots of car guys were you live now just run distilled water and an additive or even old water pump lubricant. It's not because they are too cheap to by Anti Freeze. Water cools better than Anti-Freeze.





Here in So Cal, I run Justice Brothers Super Radiator Cooler and Reverse Osmosis (RO) water in my Barracuda for the last 9 years. I also put in Justice Brothers Cooling System Protectant for added anti rust and electrolysis protection.


Very complete test of coolant additives:
http://www.turbomagazine.com/features/0703_turp_cooling_system_additives/viewall.html

"Justice Brothers' Radiator Cooler gave us the lowest temperature during our testing - 177 F - and provided the lowest average temperatures overall when mixed with water alone."




A good radiator additive does a lot more than just acting as a wetting agent. It should also provide anti-corrosion, anti-cavitation, electrolysis resistance, anti acid, lubrication, SCA's (Supplemental Coolant Additives), added thermal conduction... They should remove heat better than antifreeze. Boiling in a pressurized system of water alone is 257 degrees.

The object is to remove heat before going into a boiling situation.



Here's pictures of the inside of my Radiator from 2016, 5 years after it was installed. Just before a drain and fill.