Steve,

Regarding your discussion, are you referring to distilled water (as in the type you buy at the grocery store) or deinozed distilled water (that you can sometimes find)? It's been years since my chemistry days, but one of them is like acid. It will dissolve glass or metal containers. That's the one we should avoid. Do you recall which one? Also, your discussion makes some assumptions about the two solutions being equal in ionization and deionization. If memory serves, that is not necessarily so, but I can still be educated.

For what its worth to anyone reading this. I've been running 40/60 (antifreeze/distilled water) for almost 20 years in my Volvo, with changes every three years to the fluid. Still looks very clean for its age and almost no mineral deposits. main reason was I lived in West Texas, home of hard water, and I just kept the habit after I left.

PS, Mercedes and Preston's (5yr coolant) are great stuff. I especially like the residue it leaves if there is a leak. It helped me spot an earlier leak in my G. Preston advertises no phosphates and has the same color as Mercedes, but ????

Thanks.