Usually coolant is made up of half water and half antifreeze. But I was wondering
if we need half of antifreeze since purpose of antifreeze is to prevent freezing of
the water and also prevent corrosion. But where I live never reaches to 0 celcius
so water will never freeze. And adding antifreeze will decrease a cooling ability of
O2. So whats the lowest %of antifreeze just to prevent corrosion?

 

I used to run an 80/20 mix with a bottle of Water Wetter in my Civic. The temps drop to right around 0*F where I live and I never had a problem.

 

Water Vs. Antifreeze

Water is the best coolant. The antifreeze makers will tell you that Glycol-based coolants raise the boiling point, but even using a 50/50 water/glycol mixture, with a 15-psi pressure cap the boiling point is only 15 degrees more than plain water. If your car is not driven under freezing conditions, run pure distilled water plus a corrosion inhibitor such as Prestone Super Anti-Rust, and flush the system once a year. I don't recommend using tap water because hard water scale can block a cooling system's ability to transfer heat, resulting in overheating. Only 1/16 inch of scale can reduce cooling system heat transfer efficiency by 40%.

If freezing is a concern, use the minimum percentage of antifreeze required for your climate. A 33 percent glycol/water mix won