First off, hello everybody, I have been browsing this forum for a while but just joined recently as I picked up my e92 lci 335i. Great forum, very helpful!
Now my problem: I have a whistling noise coming from the rear of the car. I suspect it might be the muffler but I really have no idea. I can only hear it while inside the car and not outside. It sounds like very slight vacuum/whistle kind of noise that happens constantly at 25km/h. There is no relationship RPM/transmission at all, as I tried different variations of gears and RPM's and the noise persists just at around 25km/h constantly. This noise can also be heard as I start up the car. Also, as I get to higher RPM's, the noise will be more random. But the noise just happens constantly around at 25km/h.
Here's a video of the noise. If you turn up your volume you'll hear a little whistling noise at 0:04 seconds in.
I brought the car to the dealer and they thought that it was a muffler problem. They replaced the driver's side muffler, but I picked up my car today and the noise is still there
I thought about trying the golf tee mod to see if the problem would go away, as this seems to be somewhat related.
What do you guys think?