Just bought an 06 GTO with only 8,300 miles on it. While checking the fluids, I opened the little yellow cap where the radiator resevoir is located. Pulled the stick out and was amazed to see orange clay looking gunk all over the dip stick....ugh! Took it to a radiator repaid shop and had the flush and put Dex Cool back in. Two questions, what could possibly cause the Dex Cool to break down so quick and how many go back to green coolant after the warranty is out?? I've been told by more than one mechanic that Dex Cool SUCKS.