I have checked once a quality of supposed to be distilled water bought from CVS, tester showed 70+ ppm, which is way too much even for single pass distillation. Even good bottled water like Poland Spring is cleaner.oragex wrote: ↑27 Jan 2020, 07:04 Same here, and it's concentrate which means you will add another gallon of distilled water ($2 from Walmart Pharmacy) and you have all the needed coolant for under $25USD and you know it's the right type for your car. While there, I would never use tap water in these engines, not even to 'flush' them with that garden hose. In many areas the tap water has high amounts of calcium carbonate dissolved in it which only waits to deposit inside the engine and block coolant passages - remember that the heater core inner tubes are very thin.
My tap water was 14 ppm (reverse osmosis), I switched to tap water






