are there any other updates to this debate? I own a 04 comp g gtp, and have noticed some sludge around the radiator cap and some in the reservoir container. I flushed the system in the fall when I first noticed it, but did not know about the controversy, so re-added the dexcool. I have only put 3,000 miles since this flush, and don't drive the car in the winter. I do start it up twice a month and run it for approx. 10-15 min. I am still getting some resudue on the radiator cap. I assume that the first flush was not enough? I will flush it agian this spring, and will not go back to dexcool. I am under the impresion that adding the old green is not ok because of the silicone. I also read in this forum that the extended life antifreez is also not good. What is this prestone yellow stuff you talk about? Can anyone please tell me the best solution other than keeping dexcool in my car? Will more flushes get rid of all the sludge (hopefuly not allot) that remains in the system. I have looked for the Gm"12346500 heavy duty flush and can not find. I did get ahold of AS100 heavy duty cleaner though. Will one more flush with this completely clean the system?