Running Straight Water-How Long?

[SirTanon]

Originally Posted By: Warstud
Originally Posted By: SubieRubyRoo
Don't use deionized because guess what? It will leach ions from metals in your cooling system.


Where did you hear that? I think most Anti-freeze manufactures use DI water. I personally think either one is fine.


Using a pre-mixed Anti-freeze product that is made USING DI water is fine, because the added chemicals will 'fill in the gaps' so to speak.

Running straight DI water in a car's cooling system with nothing else is a totally different thing.. and I would only even consider using it for a VERY short-term flush.

 

[kschachn]

Originally Posted By: SubieRubyRoo
Never use tap water, only use distilled. Don't use deionized because guess what? It will leach ions from metals in your cooling system.

It will yes, as will most tap water unless it is already saturated with aluminum or iron.

This is one of those issues where someone reads something on the Internet or hears it down at the feed store but in reality isn't an issue at all. A cooling system is a closed system, until the surfaces are passivated metal will be dissolved but only until the water is saturated. The only time metal leaching is a problem is in an open system such as where distilled or DI water is prepared and "new" water is continuously flowing over some surface.

In a cooling system the biggest problem with plain water is dissimilar metal corrosion. Antifreeze has corrosion inhibitors for this which plain water obviously does not.

 

[Edis]

Saab used G48 as the factory fill until 2001, then they switched to G34 (Dex-Cool).

Water requirements as per BASF (Glysantin) recommendations:

Chloride content: max. 100 ppm
Sulphate content: max. 100 ppm

Water hardness: 0 – 2.7 mmol/l (G48)
Water hardness: 0 – 3.6 mmol/l (G34)

As we can see most tap water is ok, but distilled or deionized water is preferable. Dex-cool is slightly more tolerant with tap water.