There was a wonderful thread on
antifreeze vs. water a couple or three years ago, did it survive the server/system crash?
#139 runs at 80 degrees C no matter what the weather or driving conditions, I turn the fans on at startup.
Since there is no overflow tank, she gets topped off with filtered water at every preflight. I always see a bit of rusty water when she spills over, cast-iron block, I guess.