[Tweekster]

Butcher is right...that is one of the reasons a heater core works better than the multiple coil/loop type radiators....as the coolant enters the core it splits up to several passages, increasing the overall area, decreasing the coolant velocity and allowing for better heat transfer.....you can have too much coolant velocity....in car racing (NASCAR for example), they actually gear down the water pump to slow the flow for better cooling.....there is an optimum flow range