Prestone Every Car Antifreeze

I've used Evans Waterless Coolant in 6 of my 7 vehicles for many years and seen no internal corrosion since. Unlike one of the linked articles, it is not pure propylene glycol (PG), but rather 30% PG w/ 70% ethylene glycol (EG) as I recall their MSDS. Used to be pure EG, but they found that adding a little PG makes it pet-safe. Costs $43/gal, but should last forever or until your next coolant leak. Supposedly cools worse than 50/50 EG/water, but I've driven several cars over the I-5 Grapevine climb (north of L.A.) on 110 F days and didn't overheat, so works for me, and with no corrosion should never get worse. I understand that new car models are validated for cooling systems on that climb.

You might roll-your-own by buying pure EG (most brands) and PG (Sierra Coolant) and mixing. But, those spec up to 5% water, so should first boil the water off. I did that and quite interesting. Do so only outside on a grill, far from your house, and don't breathe the fumes. Once the liquid reaches ~400 F, the water will be gone you will start getting EG or PG vapors. They can ignite in the air. The first time I did it, the EG seemed to be burning with an almost invisible flame. Holding paper above lit the paper, though that happens above "Farenheit 451" (per Ray Bradbury novel). Same for PG, but the flame is more benign. Last pass, I left the grill on high too long and the EG started burning and boiling violently, splashing to the ground and melting the propane hose. Got it shut off w/ garden hose spray, but could have been worse, so decided better to just pay Evans price.