Yes, R/O water is reverse osmosis water. This process removes most contaminants in water. It is not considered "pure" research grade water though. Pure research grade water is not so good in use in an "open" system where "pure" water is constantly used unless the system is made from high grade stainless or PVC. The pure water will remove metal ions in any plumbing that is made from brass, copper, lead, etc. In a closed system like a radiator, it should be fine because it will only remove minute amounts of metal ions before it reaches equilibrium. I built an R/O system to provide 200 gallons a day of R/O water for drinking, ice making and mostly for final wash for parts I want to electroplate or paint. It is also good for rinsing steel metal parts that I don't want to flash rust so quickly. (think gas tanks after derusting) The R/O process outgasses the O2 from the water and helps keep the rust down if rinsed and dried quickly.Sidecar Bob wrote: ↑Mon Jun 09, 2025 10:36 am I think he means Reverse Osmosis filtered water.
The town water here used to be very hard, so bad that a couple of years after we moved here they closed one of the town wells and replaced it with one that has much softer water. We still have a water softener so our water should have very few minerals. I've never noticed mineral deposits in my engines or radiators so I'm not going to worry about it but if I did I would just dilute the coolant with distilled water like I use to top up the batteries.
I grew up in the mid-Hudson Valley, NY and then moved to a farm in upstate NY and deep well, hard water is what I grew up with. I mean REAL hard water to the point you used 1/3 of a large bar of soap to take a shower and putting a pan of water out for a few hours caused mineral deposits to form! Plumbing was always a problem because of the mineral buildup. The upside was...when I was a kid, on a real hot summer day, the deep, hard well water was the best thirst quencher I have ever experienced! No Chlorine taste, just straight, cold water from a well.
-P.
