Quick google found this:
Non-laboratory uses
Distilled or deionized water are commonly used to top up lead acid batteries used in cars and trucks. The presence of foreign ions commonly found in tap water will cause a drastic reduction in an automobile's battery lifespan.
Distilled or deionized water is preferable to tap water for use in automotive cooling systems. The minerals and ions typically found in tap water can be corrosive to internal engine components, and can cause a more rapid depletion of the anti-corrosion additives found in most antifreeze formulations. Distilled or deionized water is especially important in automotive hybrid system component cooling systems, mixed with hybrid system coolant, to prevent corrosion and/or electrolysis of hybrid components.
Using distilled water in steam irons for pressing clothes, as well as other appliances such as humidifiers and cigar humidors which boil water, can reduce mineral scale build-up and help the appliance last longer.
So rather the opposite regarding corrosive properties?
Then another search found this:
http://www.finishing.com/110/17.shtml a familiar name popped up on there too.