my 99 gtp had a flush at 70k miles and then another flush at 140k miles. I have the motor apart now(heads and all) and i didnt find anything like that in mine. I did both coolant flushes my self and had a good look at what came out. I also pulled the rad and flushed it by it self and again i didnt get anything like that. I am going to stick with dex until i see the problem my self