Thanks a lot for your knowledgeable reply, Ken and Mcduck. I kind of “know” not to do it at the first place. However, I just can’t get the idea out of my mind until some research. Well, I think that I got it now. I kind of learned the lesson from some other life experiences. Being a part time tree trimmer and climber, chainsaw is my other love, can’t get enough of it. Anyway, I earned from a lot of people to replace the bar oil with vegetable cooking oil, there are even detailed study about it. Yes, the vegi oil does have very similar property on metal to metal lubrication. However, just like the gunk over your cooking top, it gels, and hardens, and leaves a horrible mess after a while of use. That’s how I learned not to go down the unproven path.

Just for the sake of argument, I think that the dissolved oxygen level in the cooling system is close to zero at engine operating temperature (closed to 100 degree C) and thus the oxidation shouldn’t go very fast. Also, aluminum oxide will form a protective film on the head surface – I don’t have any evidence for this, just speculations.

Between water and 100% Ethylene glycol, water is obviously the more corrosive one, thus by diluting it with antifreeze, corrosion is reduced. Erwin