First of all, I won't waste anyone's time discussing a faulty cooling system. My comments only apply to a cooling system with a correct thermostat and a clean radiator with a proper coolant solution.

The rate of coolant flow depends on the engine RPM's. The water pump speed increases or decreases as the engine speed increases or decreases. The coolant flow increases or decreases as the water pump speed increases or decreases.

The faster the engine turns, the more heat is generated internally. Then the water pump turns faster to provide increased coolant flow to carry the increased heat away.

Engineers design the total system with every component matched. Big engines make more heat and need more coolant to absorm the heat. More coolant means larger radiators to remove the heat from the coolant. Larger radiators mean water pumps with a larger flow.

So it's obvious to a reasonable person that each cooling system component must be in balance with all other components. Replace any component with one matching the original design.

I suppose this seems absurdly basic, but some one had to mention it.

And one more, "DUH" to consider. As engine speed increases, so does vehicle speed and that increases air flow through the radiator which helps remove heat from the radiator. In fact, most vehicles do not need fans once they reach certain speeds.

Other "beat a dead horse" subjects are coolant mix ratios and "Do we need a fan?" discussions. Go for it!

I know about electric water pumps. Their flow is controlled by sensors that measure coolant temperature.

I know about electric fans. Their flow is controlled by sensors that measure coolant temperature.