[Lycoming-8]

Back in the days when I used the 1929 as a daily driver, I used an industrial blend of methanol, isopropanol, and propanol. It was available at the plant where I worked for $0.50 per gallon. We added a rust inhibitor of some sort and never had any problems until the day in mid spring that the 'A' would start to boil coming up the long hill to one of the northern Cincy suburbs. This routine was repeated every year that I drove the car, along with occasional checks of the coolant freeze point in a local lab (by me).

So non-glycol options are out there, if you are willing to experiment and have the facilities to verify protection levels.

Good lead-in Lefty !!