Also true. Regardless, the minerals in hard water are not good for engines. I always use distilled water when mixing with coolant.WhatAmIDoing wrote: ↑21 Feb 2019, 18:55 Rust isn't a concern. Minerals in your tap water which clog up radiators and small orifices in you cooling system (as well as increase conductivity) is the problem, which is why you should only use distilled water.
The only time I'll use tap water is if I'm flushing out the cooling system.






