Anti-freeze and Water

Most recent answer: 10/22/2007

Q:
Why do the antifreeze companies like Sierra and Shell request that DI water be used when mixing anti freeze for your car? Why not distilled that is available in the stores? The area I live in adds lime, soda ash, chlorine and flouride to tap water. The engine is a saturn that has an aluminum block with steel sleeves.
- Mike Barrett (age 51)
Seattle WA USA
A:
I always used store-bought distilled water. Distilling removes ions and most other impurities. Maybe DI (de-ionized) water made with ion exchange columns is cheaper. Maybe  the companies meant to include any type of DI water, and forgot to mention that that includes distilled water. Do they say otherwise?

I don’t want to mess up your car, but it would be very surprising if there were a problem with distilled water.

Mike W.

(published on 10/22/2007)