Faster is not better when it comes to engine coolant flow rate. The purpose of a radiator is to support heat transfer, which is a time-dependent process. As Flex-a-Lite explains, to move the heat from one medium to another (engine to coolant to radiator to atmosphere), the coolant has to remain in contact with a surface for heat transfer to take place. Moving fluid too quickly through an area can result in laminar flow, where the fluid forms layers. The layer closest to the surface moves slower than layers farther away from the surface. When this occurs, the layers act as insulators and the capacity to transfer heat is diminished. [/quote]

That is so wrong, if Flexalite says that I am glad I didn't buy their stuff. If you actually bothered to look up any heat transfer formulas you will see that time is not directly in the calculation but rather is expressed in the rate of flow (I.e. GPM) and in the calculations each increase in the rate of flow increases the rate of heat transfer. It matters not if it's the coolant or the air flow rates being considered.

I mean nobody suggests you turn the cooling fan slower so that the air "has time to transfer the heat". But if your supposition were true, it isn't, then it would stand to reason that slower airflow would help, it doesn't.

And there is no laminar flow in the cooling system EXCEPT in slow flow situations and in the radiator tubes. https://en.wikipedia.org/wiki/Laminar_flow