Thor, or should that be Zeus?

[Boyan Silyavski]

It will be until it completely dries out.
Far simpler option is to put some anti-freeze (or summer coolant) in, as it has corrosion inhibitors in, and will improve the cooling performance over plain water.

Exactly what i am doing. Running it on the most expensive antifreeze and distilled water. The pink one. But after 2 years maybe from the heat here in Spain, even in the antifreeze tank something develops, like a veil or to say like a jelly . So then it has to be changed or just cleaned. I highly recommend the antifreeze to be in a transparent tank so you could see if that happens to you.