While I agree that DexCool by itself is not necessarily a problem. It may run fine in many vehicles. But it won't in mine. With increasing miles, I get problems. One of them is keeping everything sealed up. It can be, and is a problem for me. Just the nature of running a car with higher miles. Every 10k miles, I need to add a half bottle of SC fluid. Every 10k miles or so, I need to add a little coolant. It leaks a little from somewhere. Am I that concerned that I am going to tear down my motor and try to find it? Nope, it doesn't leak that much. But it does leak enough that it would cause a problem if I ran Dex Cool.
Additionally, it is basically impossible to have a cooling system without air touching coolant somewhere. Even look in your overflow tank? That's right, air. So Dex Cool may work fine. But in most systems, with increasing miles, the cooling system will start to see air. If you are running a non-Dex Cool coolant, these small leaks that are not important enough to fix don't cause a problem. But in systems that do run dex cool, these leaks are highly detrimental to the cooling system, as well and the entire engine.
