NoPistons -Mazda Rx7 & Rx8 Rotary Forum

Quote:

Originally Posted by j9fd3s' date='Oct 30 2002, 12:23 AM

[quote name='pengaru' date='Oct 29 2002, 03:50 PM'][quote name='j9fd3s' date='Oct 29 2002, 05:14 PM']1. distilled water is bad, it will pull the minerals out of the engine until it gets to where normal tap water is.

WTF? every reference I've read regarding this subject says to use distilled water...[/quote]

i know, i need to find the source for my info. actually unless you have really bad tap water, it doesnt make a difference

mike[/quote]

I did a quick search via google, most results were just talking about filling cooling systems, but this guy mentioned some things that sound inline with what you said:

Cooling System Troubleshooting

I'll just paste the relevant part:

One last note. Especially in areas where the water is hard (northeast for example), use either distilled or deionized water and antifreeze. This water lacks the minerals that will otherwise plate out on the coolant wetted surfaces. When the system scales up enough, suddenly the engine detonates on even premium fuel because hot spots around the exhaust and plug are insulated by the scale. Scale buildup is a self-accelerating process too. Once there is some scale, then the extra heat in that spot causes even more to plate out.

There seems to be a huge body of myth about deionized or distilled water and coolant systems. There's a huge thread on rec.autos.tech right now with loads of myth spread all around. Here are a few: Myth: deionized water is different from distilled water. Fact: The label only addresses how all impurities were removed from the water - an ion exchange bed or reverse osmosis for deionized water and a distillery for distilled water. The result is the same - water without any dissolved solids. Myth: distilled water will dissolve the block. Fact: iron is almost totally insoluble in water. In fact deionized water that is within a percentage point or two of theoretically pure is routinely stored in million gallon tanks at power plants. This myths stems from the next one. Myth: distilled water is corrosive. No, it is not. Distilled, deaerated water is practically inert to metals. HOWEVER. In the presence of dissolved gases, distilled water will host rust and corrosion just as any other type of water will. Since people who use distilled water in warm climates think that they don't need antifreeze or an anticorrosion package since there is no minerals in the water, they tend to NOT run antifreeze. When the system almost immediately rusts up, they blame the water. Fact: 50-50 mix of antifreeze with a good anticorrosion package and distilled water is the best mix to use. If one were to look inside the radiator on my car, one would notice clear green coolant and bright, shiny metal surfaces. This is because the antifreeze/distilled water mix neither hosts corrosion nor deposits lime.

... i'm sticking with distilled water personally...