[Wayne 962]

Hmm, I think it may be the other way around, to recirculate hot coolant back into the engine when the car is warming up. You don't want it flowing to the heater core, as that would effectively just cool the coolant, and slow the warm up cycle. I think if you live in a warm environment like SoCal, it wouldn't make much of a difference. But in cold climates, it would probably slow the warm up of the engine...

-Wayne