Discussions

I work in the auto industry (not for GM) and I see this complaint often, in fact I saw one today.  
 
Dexcool antifreeze, by itself, is a very good long life antifreeze.....in a perfect world. We don't live in a perfect world and the environment your cars engine lives in is far from perfect. As I understand it, when dexcool mixes with air that is where the process of deterioration begins. A vehicles cooling system is going to get air in it sooner or later and that's when the problem starts. Over time leaks develop because of gasket deterioration and then a repair is needed to avoid possible serious engine damage.  
 
In my mind a good repair would involve gasket replacement as well as a cooling system flush and refill with regular antifreeze. If the vehicle is still under warranty I would advise using dexcool antifreeze again to avoid loosing your warranty. But if that's the case GM will be paying for it. :-)