There is at least some truth to this. Distilled water is notorious for corroding
unprotected aluminum and other metals. However, if you're mixing it with
antifreeze, the corrosion inhibiting additives of the antifreeze will counteract
the effects of the distilled water.
"John A. Simmons" wrote:
> Can this be true?
> John, '71 TR6
> Berkeley Spings, WV
> A month ago, I had the coolant system flushed in my TR6, and thinking I was
> being consciencious, replaced it with a 50/50 mixture of antifreeze and
> *distilled* water. Last night, I was reading a popular book on collector
> car maintenance and came across this:
> "Mercedes Benz and a few others have gone to the extent of specifying the
> characteristics of the ideal water to use in coolant. They make the strong
> point that distilled water NOT be used in your radiator. Distilled water is
> 'mineral hungry', and will look to your engine block and other cooling
> system components to try and absorb those minerals."
> The author says he uses a certain brand of bottled water (Black Mountain)
> that falls within Mercedes specifications.
> So now I've got to replace the coolant again???!!!
> --Phil Haldeman
Monroe, New York
The Wyvern - '57 Triumph TR3, TS15559L - http://www.merlingroupinc.com/tr3.htm
The Hippogrif - '71 Triumph Stag MKI, LE8176E - undergoing bodywork
Kitty - '83 Jaguar XJ6 Vanden Plas - Daily Driver