Straight Water for Coolant

[LCSCHADT@aol.com]

Sheffield,

91[sic]-11-3, you wrote...

> In the OLD days of hot-rodding there was an article in one of the monthlies
that said
> that in non-freezing locations nothing worked better to dissipate heat than
straight 
> H2O with some corrosion inhibitor/water pump lubricant added. It went on to
say 
> that antifreeze actually lowered the boiling point.

I'm fairly certain that the second statement is incorrect, the boiling point
IS elevated by dissolving anything in water - I think its one of those
immutable laws of physics/chemistry (but then with a solution of EG 70% water
30% - typical ratio in colder climates - are we talking about elevating the
boiling point of the EG, by dissolving water in it???  And if so, what IS the
boiling point of EG?, anyone out there know how this physics/chemistry
works?).

The first point though may be entirely correct, and is a seperate issue.  How
efficient a fluid is at conducting heat away from one area to another is a
function of properties quite independent of its boiling point: its specific
heat (the amount of energy required to raise the temperature 1 degree C -
which may well be lower for the 'glycols); the viscosity of the fluid (anyone
know if the propylene glycol antifreezes are more viscous than the EG AF's?,
I'm sure they are both more viscous than pure water); tendency for cavitation
at the water pump (I would think); air bubble formation, etc..  NOTE - once
water turns to steam, it isn't very efficient at conducting heat! (though it
is less viscous....).  The modern pressurized cooling systems (I guess) would
prevent water from boiling until a higher temperature is reached.

Jim Griffin (JGriffJ@aol.com) quotes a Redline brochure as indicating...

> 50% glycol raises head temperatures by 45 degrees F.

A Prestone bottle in my garage indicates that a 50% solution raises the
boiling point to >265 degrees F ["+265"] an increase of 53 degrees F. - so
you come out 8 degrees ahead.  I'm speculating here: presumeably the trick is
to add just enough to raise the boiling point above the typical maximum
operating temperature (and enough to offer the freeze protection you need -
that same 50% Prestone solution protects to -34 degrees F - I'm not likey to
go anywhere that would dip below 0 degrees).

About the relative toxicities of EG vs. PG antifreezes, haven't come up with
too much yet in the way of ACTUAL experience.  I did find that PG is used in
"soft-moist" pet food as a calorie source (and preservative) at 12% by
weight.  One study increased that to 41%, providing 8 gm/kg for DAILY for 5
weeks for some kittens, and found some subtle effects on red blood cells - no
deaths were mentioned in the abstract.  A SINGLE dose of EG 8 gm/kg could be
lethal, let alone a daily dose for 5 weeks!

Re: Sierra (propylene glycol), and phosphates (where this Sierra discussion
started) - there is a "no phosphate" claim on the bottle, and indeed, no
phosphates listed by the poison-dex in their listing of the Sierra
formulation. 

Later,

Larry 87 5kCQ, with Sierra x 25 mo/~20k mi.