jfo

After about 4000 miles, my 2002 C320 has developed a high pitched noise that sounds like a "weedeater" (or perhaps flying locusts) coming from the rear of the engine above 3000 rpm. It can be heard inside the car, and it is quite loud when the sunroof is open. The dealer said that there is an occasional problem with the camshafts of the 320 engine, i.e., one that they have seen on E320s and ML320s, as well as this C320, since 1997. It was recommended that a different oil might improve the problem, and a free oil change was performed. Sure enough, the amount of noise was reduced by one-half! However, it is still there. The dealer has said that MB will authorize a warranty fix that involves installing new camshafts. (Sounds pretty expensive to me.) The technician believes that it has to do with the factory machining process that finishes the camshaft surface on the bearing. Since this was recognized years ago, why does the problem still exist today? Ever heard of this one?