Distilled versus Tap Water

Here are some interesting comments from the No-Rosion.com website. According to them, the best water to use for our cars is Reverse Osmosis water, which is available at many stores and free standing dispensers.

Q. Should I use distilled water as coolant?

A. Yes. But only in a 50/50 mix. Distilled water should not be used as straight water coolant, because it can cause damage to system metals. The reason has to do with how distilled water is created.

During the distillation process, water is vaporized into its gaseous phase, so all impurities are left behind. These impurities include a number of minerals, including calcium and magnesium, the two components of hardness. The water is then condensed back into its liquid phase, so the resulting liquid is pure water. In fact, some of the purest water on earth. The problem is that distillation strips impurities from water, resulting in water molecules that are electrochemically imbalanced. So distilled water will actually strip electrons from the metals in a cooling system as it attempts to rebalance itself electrochemically. This can result in damage to metals in a cooling system.

Using distilled water in combination with 50% antifreeze effectively cuts the amount of distilled water in half. By compounding with glycol, it will not cause damage to metals in a cooling system. For this reason, it is safe to use distilled water in a 50/50 mix.

Q. What type of water is best to use as straight water coolant?

A. Reverse osmosis (RO) water. Rather than stripping impurities from water, RO filters them through a membrane. The resulting water is electrochemically stable, and not harmful to metals in a cooling system. RO water is every bit as pure as distilled water, but without the risk of electrochemical stripping of electrons from system metals.

Q. Where can I find reverse osmosis (RO) water?

A. At the local supermarket. Look for DRINKING WATER, which is available in gallon bottles. But do not confuse it with SPRING WATER, which is often high in mineral content. We have performed extensive testing of major brands and generic brands of bottled drinking water, and found that it is almost always composed of RO water.

Q. What are the benefits of using purified water, such as distilled or RO?

A. It lacks the impurities of tap water. Without impurities, its ability to function as an electrolyte is greatly diminished, thereby minimizing damage from electrolysis. It contains no hardness, meaning it will not form scales and deposits that can cause overheating. It does not contain other damaging contaminants, such as chloride or sulfate. And importantly, it enhances the overall performance of No-Rosion, allowing it to more effectively function and provide the full range of benefits that it has been engineered to provide.

Q. Can I safely use softened water as coolant?

A. No. It was previously our recommendation that softened water be used as engine coolant. This is because, like reverse osmosis, water softening removes impurities in a manner that results in water molecules being electrochemically balanced. However, we have since changed our recommendation. The reason for this change is that some water softeners do not effectively remove chloride and sulfate contaminants from tap water.

http://No-Rosion.com