If you've ever heard an engine with a collapsed lifter that is the sound I hear. It goes away fast , 5 - 10 seconds, but it is literally loud enough to turn heads. I have gotten several comments from co-workers who have been heading to their cars when I am starting mine. Knowing that this engine is right out of a Mercedes, I find it hard to believe that a Mercedes buyer would have to tolerate a car that makes people look and go "what's wrong with your car?" when they start it.