Odd cooling problem

["TBerk " at sbcglobal.net (T Berk)]

Allyn wrote:
> 
> >  Actually when you stop the engine the temperature will raise. Because
> >  there's nothing to cool the engine, no water flow inside. Haven't you
> >  noticed that after you cut the engine the fan start working foar a minute
> or
> >  two?
> 
> the fan kicks on, but this is not due to the usual temperature switch
> (radiator), it is due to a after-run temperature switch in the cylinder
> head. the intended purpose of this is to keep engine bay temps at a
> reasonable level when the engine is first shut off. this was done because
> wiring was becoming brittle in southern cars. engine bay ambient was getting
> >300f in the first few minutes after shutdown.
> 
> an alternate cause of the fan running is if the a/c was on. the a/c high
> pressure switch keeps the fan on after shutdown to help drop evaporator
> pressure, preventing damage to the a/c parts.
> 
> Al
> 
> 

My car (an 81) has no after run system. The only thing that causes the
rad fan to run when real hot is the thermo switch in it.

Oh, and no A/C either.


TBerk
should have saved it all for one post.