"On the road again" touched on something that most folks don't consider when trying to get their engines to run "cool".
Cylinder bore wear is accelerated each time you drop your engine operating temperature by five degrees. I learned this the hard way with an engine that I ran ultra-cool and had to rebore at 40K. In addition, lower operating temperatures are often the culprit when you find an engine that is all sludged up.
If you look at today's engines running 100-150K without even a valve job and at normal temperatures at or above 195 degrees, and meeting or exceeding emissions requirements, it indicates to me, that heat is not the enemy we were lead to believe.
A quality thermostat as "On The Road again" points out, along with a good efficient radiator, and a 50-50 mix of antifreeze and DISTILLED WATER is going to save you money down the road. An extra couple of bucks is pretty cheap insurance when the cost of an engine is at stake. Just my $.02 because.....
