I beg to differ with the fact that no flushes are needed until warranty expires. With GM DEX-COOL there is a line that nobody (customers) want to read/understand. It states "with the proper maintenance", which means do not contaminate the system with other type coolants, hard water, etc.
Back in '97 there were lots of people complaining stating that the dexcool has a "warranty" of 5/100, the fact is that the 5/100 is a life expectancy with proper maintenance. They were causing the "Mississippi Mud" in their systems by adding "green prestone", hard water, etc.
When the reservoir starts looking "rusty" you better do something about it before you get the "mud" in the system....
I would be scared to use anything that states it will mix with any type coolant. I have seen vehicles with mud in the cooling system by using GM dexcool and the "mix with all" coolants...
[This message has been edited by CRM SoTex (edited 10-29-2008).]