I will revert back to my earlier argument. DexCool to me is the culprit for the simple reason of its sensitivity to air. Never ever before have I had such an issue as I have had with DexCool. No other coolant I am aware of, even other manufacturers long life coolants, have this issue.
So whether or not Dex Cool is the specific culprit, the fact remains there was never such an issue with the previous generation green coolant nor any of the non-GM long life coolants I am aware of. The fact that such debris and sludge can build up in an engine, even if it is due to leaking gaskets or air infiltration, such as that which I posted earlier in this thread is cause for alarm. The fact it does not occur with any other coolant I am aware of throws the suspicion at Dex Cool.
Now, that said, one thing I noticed and I believe was discussed even on this forum, with regards to the air contamination, was the position of the radiator cap. In its current position on the 3800 engine and others that I have seen, you cannot possibly fill that radiator to such a point that there is no air in it, even if you do bleed the system.
Once that point was brought up I began researching that and guess what. Jay Dankovich of General Motors even brought this up in a convention in 2001 in Orlando Florida. So the fact remains that Dex Cools sensativity to air again points to it being the culprit. Anyone ever tore down an engine that ran any other long life coolant or green coolant that had the sludge in it that mine did or had the deposits and slugde that others have experienced? Not that I am aware of.
In all the research that I did way back when, and it was alot as I wanted badly to put to rest this argument one way or the other, I came to a few conclusions:
1. Dex Cool is HIGHLY, maybe even ABNORMALLY sensitive to air.
2. Some cooling system designs have inherent design flaws that not only promote air intrusion, but make it nearly impossible to get rid of.
3. The design flaws in gaskets, predominantly in 3800 engines further aggravated the air intrusion issue.
Now, I alieviated my air intrusion issue. I did this by using a coolant filter on the outlet hose, on the drivers side of the radiator. Because this hose is higher than the radiator fill neck I can now fill the radiator completely. So much so that I no longer have to bleed my system when I drain the coolant.
So one can make all the arguments for or against Dex Cool that they want, but the fact remains that, even if its a set of circumstances coming together such as the use of Dex Cool and air intrusion or gasket failure, no other coolant has demonstrated the destructive properties under such conditions as Dex Cool has.
I have heard countless reports of 'etching' caused by Dex Cool. It wasnt until I pulled the heads off my engine and saw the crap that was trapped in there that it made sense. Its not the Dex Cool per se, rather it is the sediment that it deposits in a cooling system once it sees air exposure and that grit circulating within the engine and cooling system.
