At about 3000 rpm, in any gear but most audile with windows open and at lower speeds, an intermittent rattle that sounds like it is tied to the induction/cam system comes and goes. Never happens when car is standing still regardless of RPMs. It is an additional rattle that is tied to the RPM. My mechanic has listened to it and is mystified. I told him I would ask the mighty mighty BMWCCA community for help. Thoughts? I just had him replace the cam position sensors and after that work this noise developed. Thanks folks!
N52 and no, I do not have a video. Here are the circumstances. Engine warm or cold, most definitely warm. Intermittent sound. Comes for a few seconds then stops. Occurs mostly around 2500-3500 rpm. Doesn't matter what throttle position, mild acceleration does it a lot. Won't do it when the car is not moving. What it sounds like: a rattle. tied to the engine speed. fairly loud, no mechanic could miss it, plenty of numb drivers would never hear it. Definitely from the engine. That is about all I can give you. I'm not sure a recording would capture it, but I can try tomorrow. The car goes to the special BMW mechanic in my town next week. Why don't I always take it there I ask myself? Money, but maybe this is a lesson.
Hard to say without hearing the noise. Couple things you can try is shut off the a/c and see if that changes the noise at all. Also has the tech removed the drive belt to see if that changes the noise? If the engine is internal to the engine has the oil filter been pulled and looked at for any metal shavings?
