Quote:
Originally Posted by dataway
I did once have someone tell me that removing the thermostat can actually cause an engine to overheat because the increased flow rate and turbulence reduces the systems ability to transfer heat, as the components, passages etc. are designed to operate within a particular flow rate range. No idea if it's true or not.
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I think this is one of those shadetree myths. As someone pointed out on a different cooling thread, if you look at what the factory did in every case where higher cooling capability was called on, they took steps to increase coolant flow and increase airflow across the radiator (and/or increased radiator size).
Think about it this way: Whether the coolant is moving fast in the engine or barely moving there is always *some* coolant adjacent to any given piece of metal. The difference is that if you don't have enough flow you might get too much heat into a given "chunk" of coolant before it gets a chance to cool off in the radiator.
Or think about it this way: If the coolant didn't move at all the radiator would always contain really cool coolant (ambient, pretty much) and the engine would just heat up until it melted. At the other end of the scale is where you have coolant moving so fast that coolant temps in the engine and radiator hardly differ. At this point it's just a straight-up battle between how much the radiator can cool and how much the engine can heat. All slower coolant flow gives you (eventually) is a bigger temperature gradient between the radiator coolant and engine coolant. Since the coolant in the radiator gets cooled based on the differential between radiator coolant temperature and ambient air temperature you get best cooling with the highest radiator coolant temperature for a given (same) engine coolant temperature. That means you want this differential between engine coolant temperature and radiator coolant temperature to be as small as possible. And since you already know what engine coolant temperature you want the way to get there is by reducing this differential with more flow.
Sam