[TRADERMIKE 2012]

Originally Posted by Sirrotica

There is another reason to spin the water pump at a higher speed, it increases pressure in the cooling system to help eliminate steam pockets in the cylinder heads.

As far as water traveling too fast, and a restrictor helping to cool an engine better. The absence of a thermostat lowers the pump pressure allowing steam pockets to form more easily, so if you put a restrictor in the thermostat housing it also eliminates the steam pockets by raising pressure. Having a restrictor, or thermostat, plus speeding up the water pump raises pressure. These 2 items work in conjunction to stop overheating.

This is where the myth starts about slowing down coolant, if a casual observer sees a restrictor helping the O/H problem they "assume" that the water is traveling too fast to reject heat. If that theory had any merit the coolant also wouldn't pickup heat from the engine, but the coolant definitely has no problem picking up heat as it passes through the block, therefore that myth is busted.

Electrons are how coolant releases heat into a heat exchanger/radiator, so as JL has said, it happens instantaneously. When steam pockets form the coolant is in a gaseous state, steam/gas is a much poorer conveyor of heat.

Steam pockets are the same problem that can cause a nuclear reactor to melt down. If the dome is steam bound and the water can't get to the core to cover it, more steam forms multiplying the problem. Venting steam in this situation is the way a reactor is saved to allow liquid to cover the core again.

When the hottest spots in the automotive cooling system, the cylinder heads become too hot, steam forms, and more pressure and flow is how it can be taken back under control, or stopping the steam from forming in the first place.

Mikes reply:

Good to use a higher rated Radiator cap and a HD Thermo activated clutch and Water wetter. IMO