[themoose]

I've heard more than once that the faster you push the coolant through you radiator the cooler your engine will run.This is true only to a point. I've also heard guys say that you should remove your thermostat to allow the coolant to cycle faster through the engine to keep it cooler and I have heard others say that if the coolant cycles too fast through the engine and radiator that it will not have enough time to transfer the  heat and the engine will run hotter. The truth is somewhere in the middle.The question of how the flow rate affects engine temperature is very complex and depends to a great deal on the radiator. A higher flow rate will decrease engine temperature to a point and then will go the other way all being relative to the designed of the radiator and its low or high flow limit.
Heat is conducted from the engine into the coolant, the coolant is pumped to the radiator, and the heat is transferred by convection to the air. In the low flow limit the coolant leaves the engine at thermal equilibrium and additional heat can only be removed by increased coolant flow (assuming constant engine temperature). Similarly with the radiator, in the low flow limit the coolant leaves the radiator at thermal equilibrium and additional heat can only be removed by increased coolant flow (assuming constant ambient temperature). In such a case the cooling can be described as flow-limited and increasing your flow rate will increase your cooling rate.
If you increase your coolant flow you will eventually get to the point where your coolant is no longer at thermal equilibrium with your engine. In other words, the coolant is leaving the engine at a lower temperature than above. At that point the system is no longer flow limited and further increases in coolant flow will serve to further reduce the temperature of the coolant leaving the engine.If you still continue to increase your coolant flow you will eventually get to the point where your coolant is no longer at thermal equilibrium with your radiator. In other words, the coolant is leaving the radiator at a higher temperature than above. At that point the system is radiator limited and further increases in coolant flow will only serve to further increase the temperature of the coolant leaving the radiator. This would continue until the temperature of the coolant leaving the radiator was arbitrarily close to that of the coolant leaving the engine.

Moose