[ozy]

Hi Brett,

I would not use deionised water for three reasons, first due to cost, second due to necessity - it brings no value as the moment it circulates in engine block and radiator it is no longer deionised, and third, because it can do damage.

To explain the third point you need to understand what happens in the deionisation process - using an ion exchange resin, the metal cation contaminants are replaced with protons ( H+), which will have the corrosive effect of a weak acid hence causing the problems you wish to avoid.

If you live in a hard water area and are worried about dissolved hard water salts and cost doesn't matter then you need source DISTILLED water instead of deionised.

The Barrs leak is a good idea as a palliative treatment - after all it's been around for years and is very effective, I would bung the solid in as well as the liquid carrier. Using antifreeze is not a problem providing you use a glycol based product - some cheaper antifreezes use methanol as a freezing point depressor which can have the same effect as a weak acid - or deionised water. You can check this by rerading the CHIPS symbols and componenets listing on the side of the antifreeze bottle.

I would stick with using Bluecol combined with tap water/distilled water at recommended concentration for a temp min of -12 deg C .
Hoping this helps,

Ozy