Our Hondas often come on for about one minute after the car is swithched off.
I am sure there is some cooling effects from the air going over the engine
but not much.
John
>Terry,
>
>Not particular important, but I thought I'd mention it anyway since you
>brought the subject up. I don't believe (and I'm sure other people will
>disagree with me) that leaving the fan running after the engine is shut off
>will help very much with the temperature rising after the engine stops.
>
>The reason the temperature rises is heat soak - the engine is hotter than
>the coolant, and since the two are in contact with each other, the heat is
>transferred from the engine into the coolant.
>
>Of course, this happens all the time when the engine is running, too.
>Except that when the engine is running, the water pump moves the coolant
>away from the engine into the radiator before it gets too hot. Once the
>engine has stopped, there is no movement of the coolant (except a very
>small amount due to convection) so it just sits in the block getting hotter
>and hotter.
>
>The reason I say that the fan won't help much is because the fan cools the
>coolant in the radiator - *not* the coolant in the block. And when the
>engine is not running, the water pump is not turning, so it's the coolant
>in the block which is heating up, not the coolant in the radiator.
>
>Of course, if you're happy with the way your car is wired, that's fine.
>But my fan is wired through my ignition switch (by a PO, not by me), and
>I'm quite happy with that.
>
>As always, any thoughts from people who know more about this than I do are
>welcome!
>
>Dean
>--------------
>
>
>
>Date: Tue, 3 Apr 2001 18:28:48 -0700 (PDT)
>From: Terry Thompson <firespiter@yahoo.com>
>Subject: Re: Switched power for fan
>
><snip>
>
>And also the
>temperature seems to increase when you let the car sit
>for a few minutes (pressure cooker affect?). When you
>run into the store for five or ten minutes, it's
>actually hotter than when you got there. So I like
>having a fan that runs for a while after I get out to
>drop the radiator temp.
>
>- -Terry
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