I have a trip coming up next week in Max north of me with not much stop and go traffic but usually allot hotter that way like 100. 80 is a high for here so I don't ever notice any rise in the temp gauge but do remember last time I went that way and it was a hot one Max would not overheat or anything but act different at idle stubbling a bit. So thought maybe I would test out a different mix now it is just 50/50 standard coolant.
A few of my old timer customer's with Flat head engines swear by plain water and add a quart of Soluble oil for lube and corrosion protection. http://en.wikipedia.org/wiki/Cutting_fluid
all my cars have 50% antifreeze 50% distilled water and a bottle of water wetter and seem to never overheat. BUT I do have the biggest aluminum radiator that I can fit in my coronet and dart. the coronet has a shroud and backup electric fan on a switch that I control. the dart has no shroud or elec. fan. and I have never seen it over 205* even at 105* temps at Carlisle last year. overheating sucks!
Andy, being in the heating industry (what's that you say?) I use glycol to protect certain systems from freezing. What I can tell you is that as the % glycol goes up, the heat transfer efficiency goes down. So if you think everything is OK in Maxs' mechanical world, then I might suggest you lower the glycol level to minimum for corrosion and any possible freezing Max might see. That might be why others swear by water.
President, New England chapter of Coronetaholics anonomous.
I drained my radiator and it was very dark green like pure glycol, so your on to something there Rich thankyou for the input.
So I decided to see if this mix will help out: 8oz soluble oil, 16oz Wetter water, and rest distilled water. Beer was because it was a long day at work.