Re: Cooling questions: Dang, wrong twice in one week!

Date: Sat Jun 06 1998 - 01:33:45 EDT wrote:
> This was posted earlier in the week...
> > >Here is my 2 cents worth. I don't remember where I read this, but here
> > >it goes:
> > >
> > >When you change the thermostat to a lower temperature, you risk the
> > >possibility of overheating. I know, it is hard to believe. The
> > >explaination starts with temperature differental between ambient
> > >air and water temperature. The higher the differential between ambient air
> > >temperature and watter temperature, the more heat transfered from
> > >the coolant to the air. By lowering your coolant temperature to
> > >180, you are lowering the temperature differential by 15 degrees.
> > >This means you
> > >have to make up that 15 degrees in heat transfer somewhere else.
> > >
> > >I'm no expert, this is from a magazine I read.
> Yes, you are correct. After reading the email from my brother, you
> do indeed have to "make up" the heat transfer somewhere else. The
> difference is made up by moving more coolant through the radiator.
> I now understand the "possibility of overheating". If your 180
> stat won't open wide enough or if the radiator restricts the flow of
> coolant, then you will not be able to move enough coolant to remove
> a sufficient amount of heat from the engine. The coolant flow at 180
> degrees must be greater than the coolant flow at 195 degrees.

You must also realize that if you flow too much through the radiator as
in no thermostat, you could still overheat since the water does not have
the time to transfer as much heat as it would have with a thermostat.

I know you can overheat without a thermostat 'cause I did it. Had a
fancy five core radiator built and ran without a t'stat. needless to
say it would overheat. Put the t'stat back in, and we were back to
> To the original poster, I apologize for jumping on your message. I
> have now seen the light (heat?).

No problem, I'm still looking for the magazine article, it's around here
> This is the second time I've been wrong about a cooling question
> this week. I think I'll stick to computers and let the "experts"
> handle the heat transfer stuff. All of that college physics leaked
> out of my head a loooooooong time ago. :^)

We are here to learn and help. I am still learning!


Thomas McCabe
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