If you've had old cars, you've probably at one time or another had one that would run hot. I haven't had a hot car in many years, but my 61 that I recently purchased, over heats on long drives over 70 MPH. I slow down to 65 or less and it cools down. I know, I know, "then don't drive fast". My question is, this car was purchased from Arizona and has no thermostat. As a kid I remember being told that if it over heats, to yank the thermo to help it run cooler. I also heard that it might run hotter because the thermo will restrict the flow some and hold the water in the radiator longer so it can cool? I've always known there has to be a correct answer and also a lot of opinions but usually, my problems were not thermostat related.