Regarding the restriction of the thermostat; restriction is more-or-less
proportional to length divided by area. You can't compare areas of radiator
opening with thermostat because the length of the radiator tubes
dramatically increases flow resistance. However, in many if not most cases,
some restriction at the thermostat is good insofar as it increases pressure
within the motor which reduces local boiling. But if the restriction
reduces flow too much, then cooling efficiency at the radiator is reduced
because the temperature of the coolant drops excessively as it flows through
the radiator.
Bob
>My two cents on the thermosthat - it seems that with any thermosthat wide
>open there is still a restriction because the opening in the thermosthat is
>only about 50% of the opening in the hoses and radiator inlets/outlets. It
>sounds, therefore, that any drilled holes might increase flow. Mark
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