Not a problem Mike.[img]i/expressions/face-icon-small-smile.gif[/img] That's what the forums are for[img]i/expressions/face-icon-small-happy.gif[/img]

 

My 400 did the same thing. The noise went away after the engine got more hours on it ....

I believe it was coming from the oil pump but I was never able to tell for sure. I figured that as the oil heated and thinned the pump began to make some racket at idle - the noise always ceased as the RPM and oil flow increased.

If it were a valve train problem the noise would be worse when the engine is cold, and it would get louder and faster with increased RPM, however that wasn't the case with mine.

There was a discussion here some time back about this problem, and it seemed that most guys experienced it on the 425 and 500 engines. I wouldn't be too concerned about it. If you do happen to find a cause let us know.