Good call, Steve. I'm very eager to find out more about this.

I've been using Dexcool for 90,000 miles and two years, in a 4cyl with plastic tanked rad.

I always run between min and max. Never low. The coolant does pretty much have a 1-2 year shelf life, as I change water pumps with the timing belt, unless there is no play in the unit whatsoever.

I've never found any deposits in the coolant at all. The only visible precipitate is ON the coolant pressure cap, and it is a fine film of it. The coolant tank used to have a little bit of coolant junk on the inside, but now is very clean. I actually like the stuff, but I'm also willing to try the glysantin formula that you've mentioned.

Additionally, my brother has been running a 1/2 mix of 50/50 dexcool and 50/50 green. This wasn't my doing, but I wasn't motivated to correct it on his old car. Also a plastic tanked radiator, now going on 2 years, I think. Again, no problems, but time will tell if there is any debris in the cooling system. From the looks of the tank, there is LESS debris in the tank than there used to be.

I think that Mulla Fuqua's dexcool problem is related to electrolysis, by the sound of the weeping engine block. If I'm not mistaken there was a sign of that problem using the yellow coolant as well. It's a common issue in the marine environment, so why not the automotive one? Save for salt water, which accelerates it, the conditions aren't far apart. More humidity in the marine environment, but in a closed cooling system it's about the same as anywhere. The key to solving it is to identify any voltage drain to or through the block, and to change coolant EVERY year as a precautionary measure.

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Chris Herbst, near Chicago, IL. 93 940, 91 240, 90 240, 88 740, 87 240