Deionized water for coolant? Good idea?

Yes, there is a valid term “hungry water.” It is a geologic term, used to describe sediment-starved water in channels and its effect on erosion. But folks in other specialties (physiology, automotive) have borrowed the term without any true basis for doing so. And that is what Tom&Ray have done on one of their programs. Amusing, but meaningless in that context.

And Keith asked about a previous thread. I did not participate in that one. For those still interested, here it is:

http://community.cartalk.com/discussion/2279784/the-hungry-water-theory/p1

Steve, this is the latest thread. I’m talking about one 4 or 5 years ago, maybe more. It started as a result of another caller to the show who brought up the hungry water theory.

Deionized water would be good, but I think distilled water might be better.

jaansu, what is the resistivity of your water? If it is less than 1 Mega ohm-cm, it is safe to use in your car. If it is ultrapure water (18 M ohm-cm), then don’t.

Yes, there is such a thing as “hungry water”, but it only applies to water which has an extremely low ionic content. Distilled and reverse osmosis-purified water is not purified enough to be “hungry,” and as for deionized water, it depends on the specifications of the water purifier.