Reply to "Radiators?"

Tap water is not universally bad for cooling systems. In the town I formerly lived in we drank well water from the tap which was very hard, I had to use bottled water or RO water in the cooling system, as the tap water would leave a lot of scale and deposits in the cooling system. However, the tap water in Ventura is very low in deposits, I have no reservation about using Ventura's tap water in the cooling system.

The cooling system wants water that will not leave scale and deposits, while at the same time not corrode or pit the metal. Softened water is the best choice according to NoRosion. A softener exchanges positive sodium ions for positive calcium and magnesium ions. I would think that makes softened water an excellent electrolyte, yet Norosion recommends it. NoRosion claims water with a depletion of ions is to be avoided, i.e. double distilled water, de-ionized water, high purity water, ultra-pure water. Of course, the depletion of ions is what makes those types of water poor conductors.

The additives in coolant controls a lot of the problems associated with corrosion, but those additives deplete with age and/or use, therefore the coolant will become corrosive with age and use. This is why the cooling system should be drained and refilled with new coolant every 18 to 24 months unless your coolant treatment specifies otherwise. For instance, Norosion claims if you add their treatment every 12 months you can extend the coolant service interval to 5 years.

-G