Quote Originally Posted by ronniejoe View Post
Mr. Fuller is/was a training instructor. He can offer some good insight. However, his comment about the "coolant flows through the engine with no restriction whatsoever and travels too quickly to absorb enough heat" is not sound from an engineering perspective.
Very diplomatic!

The same logic would argue that, to keep cool in the summer, you should run your fans as slow as possible so the air has more time to absorb heat from your body...

One other thing that some thermostats contribute is blocking off the bypass passage as the engine temperature increases, forcing more coolant through the radiator.