> Date:          Tue, 31 Mar 1998 11:40:52 -0800
> From:          Ian Cameron <ianc@UVIC.CA>
> Subject:       Re: Head (gasket) fix

> At 12:10 PM 3/31/98 -0500, EMZ wrote:
> >     Pure H20 and anti-freeze is the best. Prestone is now selling
> >     water for cooling systems. It is 99.9 % H2O. You can use any
> >     anti-freeze you want, but make sure you use pure H2O with it.
> >
> >     If you do you will not have a problem again.
> >                   ERic
>
> You may be right in saying that water is a critical factor.  It makes
> sense that 'pure' water would be less corrosive than water with a low pH,
> or water with minerals, for instance.  So if someone has been keeping
> track of the replies on the 'head gasket replacement' thread, take a look
> at the locations.  If water quality is a criterion, people liveing here
> in the Pacific Northwet should have no problems, given that our water is
> very soft. (Except, of course, for those who use well water.)
> >
>

Actually, pure water is *extremely* corrosive.  Sort of a corollary to
"nature abhors a vacuum" - pure water 'wants' ions, badly enough to
corrosively attack most metals it comes into contact with.  That's why here
in the Pacific Northwest, where the natural water supply is nearly of
distilled quality (very little hardness) they actually *add* hardness (i.e.
ions) to reduce the corrosivity, prolonging the life of the water
distribution system and household piping.

Furthermore, it's worth noting that antifreezes are typically *designed*
for use with tap water, not distilled water.  That is, the inhibitor
chemistry is specifically formulated to work in concert with the
concentrations of calcium, sodium, chloride, carbonate, sulfate, etc. that
commonly found in drinking water supplies.  Using water that is unusually
high or low in these compounds may actually impair proper functioning of
the inhibitors.

-Wes

Wes Neuenschwander
Seattle, WA
wesn@eskimo.com