Radiator Cap

Tom Cloud cloud at peaches.ph.utexas.edu
Mon Oct 13 21:57:57 GMT 1997


> ....................................................... As for the
>higher temp thermostats, I believe the reasoning is the higher opening temp
>makes the water stay in the engine longer in order to absorb more heat from
>the engine. Use too cool a thermostat and the water doesn't have enough
>time to leech off enough heat, totally remove the thermostat and you risk
>actually overheating, not necessarily boiling over but overheating the
>engine. Water temp doesn't mean a damn thing, it's the block and head temp
>that counts.

now, here's where I have a problem -- probably showing just how cirrusly
uninformed I really am !!  ..... I used to make water-cooled heatsinks.
Doesn't mean I knew anything.  As long as the water contacts the
metal, what difference could it possibly make how fast it moves.
IMHO, this is the most ridiculous line of reasoning I've heard in a
long time (no offense to you, Chris, ... I assume you're just repeating
what you've heard or read -- seen it in some radiator ads myself).

I mean, it's a law of physics that delta-T is required to remove
heat .... and if you leave the water there, it warms up and then
doesn't remove as much heat !!!

I'd like to know .... not really losing sleep over this, but surely there's
some guru summers that can ease my tortured mind ???  (I mean, I've
run lots of engines with no thermostat -- always assumed the only problems
were due to water not getting up into some high places that collect
air pockets and the engine oil not getting hot quick enough to lube
at first start.)

What difference does the rate of flow have to do with heat transfer ??
Like I said, seems to me that it's totally irrelevant as long as the
liquid stays in contact with the metal -- in fact, seems t'me that the
faster the better, since that keeps the delta-T at it's highest !!

At this point, I pronounce the ads by the rad makers "HOKUM".  Now,
someone prove me the idiot that most have long suspected  ;-)

Tom Cloud

   Warning, dates in calendar are closer than they appear !



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