'It isn't the gunk that comes out that I care about, it is the gunk that is loosened up and doesn't come out. I stand by my claim that these treatments are not necessary, at best cause no harm, and at worst can ruin your engine.' REPLY: Have you actually seen the Bilstein Flush Machine in operation by a trained person ? If not, then you should refrain from denouncing it until you have seen it in operation and have some conclusive emphirical evidence to accurately report on . Lastly, what is your basis for assuming that the sludge doesnt come out ?