As many of you know, I don't fall in to the DEX killed my gaskets. But I looked at everything I have here with a very open mind. I will give all the data I have here and let'* see if this helps us get closer to a answer.
My engine had DEX in it up to 92,200 miles. I know this to be fact as I removed it and I keep good records. The last just over 10,000 miles is on Peak coolant. I switched because I like the green and it'* easier to see.
I looked at my gaskets real close, and they were failing. As you can see in this picture there was some foam but it looks like there was very little mixing of the coolant and oil.
Looking closer one part fell off with very little pressure.
As you can see the design of the gasket gets very thin in the area it broke. This was done to provide room for the different gasket material.
Another view of a different area. This plastic is rigid just like a new gasket and does not appear to be softened in any way, it'* contact point to the rest of the gasket simple broke away.
Here I have removed the rubberized part of the gasket to expose the under side. You can clearly see there are small holes to allow the rubberized gasket to be held in place. This further weakens the support.
Another angle showing how the inner part of the hard gasket material broke away.
Here I was able to remove the rubberized part without breaking away the plastic part. From the looks of all the coolant jacket openings. The flat area is broken and pulled in and the corners still hold.
The rubberized part of the gasket can then move along it'* base reducing the sealing area and allowing coolant to leak from underneath. I see no softening of the gasket what so ever. I clearly see a total failure of the gaskets base. Gasket failures are the result of poor gasket design, not the coolant it'* self.