john:

maybe we can get a chemist to comment; but, it seems logical that
distilled water would actually be more corrosive than average tap water.
there may be some advantage in terms of reducing mineral deposits, but
distilled water should really be more corrosive because it is farther from
chemical equilibrium with respect to cooling system materials.

dan

On Thu, 29 Apr 2004 11:55:43 -0400, John Runberg <jrunberg@MAC.COM> wrote:

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>> So, for the sake of those of us who aren't clear on this, what are the
>> actual chemical strategies to which you are referring and which major
>> coolants, of what color, represent these strategies?
>
>The most conservative advice I've received is to use what VW spec'd which
is their phosphate-free blue stuff and distilled water ONLY. I'm willing
to play it dangerous and use other phosphate free coolants, however the
distilled water rule still applies. Even if there's no difference in
corrosion prevention (and I think there is...), the limited cost involved
makes using phosphate-free a no-brainer.
>
>john