Well, I went to my local KMart to buy some distilled water for my coolant drain and flush. All 1 gallon jugs were on sale for $0.50! But I get there and instead of distilled, they have "purified" water. The method described on the bottle says "reverse osmosis" It didn't say steam distilled or anything else. Now I know what reverse osmosis is... but stubborn old me is looking for just plain old distilled water. Does anyone know if this is a good replacement for distilled?

 

I would stick to distilled if you can.....I believe there are still minerals in the purified water

 

Let me question the use of distilled water. The reason I say this is because I previously owned a Mercedes Benz, and they specifically warned against the use of distilled water. They claimed that their research showed that the use of distilled water leached minerals out of the metal in the radiator.

 

My parents have 190Es and I also recall this.

 

so , if this is true what are we going to use ???

 

Use whatever Toyota/Lexus recommends if you are going to use their anti freeze in your car. Benz I'm sure uses and recommends a different formulation of anti freeze for their cars.

 

Toyota recommends using only distilled water in the cooling system.

Or the new premixed SLLC coolant; where the coolant is used to flush any old coolant, per it''s bottle instructions. .

 

So distilled in the lexus... but is purified water as good? Reverse osmosis is supposed to be free of minerals also. So any reason not to use purified water?

 

As suggested, purified water retains suspended minerals and is not pure. This is not steam distilled purified water, which is pure.. Supermarkets, as you're aware, sell it. The jug must state "steam distilled".