I have researched Evans as well as other coolants to no end.
The good news with Evans, is that it is a coolant that does not boil out of your radiator at high temps and creates no pressure...actually there is nothing wrong with pressure...it's a good thing when managed correctly and the boiling protection is something that you should not need either. One other good thing is that it's very stable and you don't have to change it as frequently, if at all. But, that is the limit of it's good points.
The bad is that non-aqueous proplyene glycol is not as good as carrier of heat as other coolants (ethlyene gylcol and water). Therefore you will have to move it alot faster to just keep up with regular coolant heat transfer which requires a higher flowing system. The other issue with the stuff is that it acts as a super surfactant and turns gaskets in to jelly. I have seen this very same thing with water wetter from time to time. The early Evans products required mechanical changes in your cooling systems as well. I believe they are past that with a new generation of product.
The bottom line is that it's expensive, not commonly available should you lose some, and is a poor heat carrier when compared to the common coolants.
If you have a cooling system that is designed correctly you don't need the stuff and moreover if you have a borderline cooling system, it may degradate the systems ability to carry heat and adequately cool the engine.
I do recommend Evans for those situations where for some reason, the system will not keep it's contents due to inherent hotspot formations. This is where it can help, or if you never want to change coolant again.
My recommendation.... use it if you want, but you shouldn't need it?
ConceptOne Pulleys and Brackets
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[This message has been edited by HOTRODSRJ (edited 05-30-2002).]