Does anyone know if there is a difference / preference / justification for using either straight tap water vs water that has been processed (soft water)?
The tap water in my area is extremely hard. I know it has started to effect the faucet aeriators in my house after only a couple of years.
Since I've had a water conditioner installed I was wondering if it might be better for my car. Although the process does use salt to treat the water I'm wondering if that would be better than all the minerals and additives that have gone into the radiator in the past.

Just curious

The soft water sure helps when washing the car - NO SPOTS!

 

The only thing I've put in my cars for years. I don't know if the salts in soft water precipitate in the radiator or not, but for the 79 cents a gallon and the little bit of water a car needs, distilled is the only way to go. I for damn sure wouldn't put water from the Silicon Valley into my car! Hard as rocks!

 

Distilled for radiator, washer, battery etc........Soft water for washing.

 

Yep: What mini-b said.

 

That's what that new car wash system is, I forget the name of it, but it's basically a mini water softening system.

 

ok, this is uncertain hearsay:

10 or 15 years ago i recall reading in a car magazine that the then current antifreezes were designed to work with tap water NOT with distilled water. it was something about needing the trace minerals for proper chemical action blah blah blah.

i will try to look this up.

in the meantime, somebody (maybe me) should question a chemist at one of the antifreeze companies.

 

I thought I would chip in here since I've had a little experience with distilled water in the radiator. Years ago I had a Fiat 124 Sport Coupe. Lovely car :smile: I took it apart when it had about 100,000 miles on it and took the engine to a local shop that specialized on Italian cars. He did a great job on the machining and as I was leaving told me to use distilled water in the radiator. Which I faithfully did for the next 10 years and roughly 200,000 miles. I sold that car to a guy that only wanted the engine because he was rebuilding his old 124. He called me when he pulled the head off and told me that the water jacket inside the engine looked like it had just been rebuilt. The inside of radiator also looked brand new.

We all seen the pictures on the Prestone bottles that show a clogged radiator. Where does all that stuff come from? It's not coming from the antifreeze! All that stuff in the water eventually precipitates out and ends up on the engine or radiator. I never use anything but distilled water and fresh antifreeze in the radiator.

I can't answer the question about the need for the minerals. I'm a mechanical engineer not a chemical engineer. I am very sceptical that it would matter. Perhaps they do some things to the antifreeze to make it minimize the effects of minerals in the water but I doubt that they require the minerals.

On a side note. I also noticed something interesting about the statement on the Prestone bottle that it prevents boilover up to 274 deg F. Being a mechanical engineer I had to take thermodynamics classes in college. We studied steam under pressure. I discovered that the boiling point of water at 28 psi is 274 deg F. You would get 28 psi of pressure in your radiator because air is 14 psi at sea level and you have a 14 psi pressure cap on the car. That ends up to be 28 psi of pressure on the water. So my question is, does the antifreeze really protect from boilover up to 274 deg F or its really a function of having a pressurized cooling system?

 

I strongly urge you to only use distilled water in radiators, or any cooling system for that matter. The trace minerals in tap water, bottled water, soft water, are heavy enough to set up an anode/cathode circuit between the different metals of the engine and cooling system (iron, steel, and aluminum at least). In short, it promotes oxidation (rust) in spite of antifreeze. And this isn't even considering that over time the minerals will settle out and bond (scale) to the water jacket passages and within the radiator core.


BTW, when buying a used car, looking in the radiator is a great indication of how well a car has been maintained (if at all). :smile:
cheers,

 

Thanks to all of you for your comments - I'll be sure to only use distilled water from this point on (although now that I'm on my 3rd coolant reservoir tank I haven't had to top of the radiator in months).

 

I think I will go and buy stock in water distillation equipment manufacturers.......there could be a run on them........