Re: Cooling fan run on

[Godfrey DiGiorgi <ramarren@domain.elided>]

Once stopped, an engines coolant does not merely sit still. As it cools, 
it continues to move through the system slowly like an old thermosiphon 
system. If the fan is left running for a while, the radiator cools faster 
than the engine and keeps the coolant flow going for longer, reducing the 
cylinder head's over-temperature rise by some amount. Also, remember that 
there are a lot of other components in the hot engine compartment ... 
keeping the cooling fan going helps to keep engine compartment air 
circulation up and prolongs the life of items like batteries, hoses, 
electronics, etc. 

In my MR2, there is actually a thermostatically controlled fan in the 
mid-engine compartment to help keep air circulation up even when the main 
radiator fans are up in the nose with the radiator. 

Godfrey

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