Last week I noticed a small white coolant stain by the gasket for the t-stat housing on my truck. I changed the gasket, t-stat, and upper radiator hose. I used a Motorcraft t-stat, but it looked slightly different from the original one I took out (slightly longer spring with more coils). I filled the radiator up with G-05 and distilled water. I tried for a 50/50 mix, but there's more coolant than water. It is probably closer to 55/45 or 60/40. I did bleed the cooling system afterwards and I'm fairly certain I got all the air out. Anyway, I have noticed since the change that the truck runs a few degrees hotter than before. Typically the Scan Guage would show 191-193 *F before the change, and now it generally stays between 193-197 *F. I know it is not a big difference, and well within what an all iron engine can handle, but it does have me curious. What would cause it to run hotter? More coolant than water? The outside air temperature has gone up some too, so maybe that is adding to it? The factory gauge still stays right where it was, which isn't surprising considering how informative Ford gauges are (not very).