Coming home Tuesday from work in my F30 335 after I got off the freeway I started hearing a noise like a chipmunk caught in the accessory belt. Chattering, screeching, whistling. First thoughts I had were the 1: belt slipping...but it looked fine and it's fairly new. 2: Rear main seal. 3: Turbo bearings. Noting the majority of the sound seemed to be coming from under the car by the right front wheel....#2 and 3 remained high on my list. A bit of searching around suggested PCV valve issues. Well...my car does have 180,000 miles on it and the original valvecover (gasket's been changed twice, once by me.)...so that seemed like a reasonable place to start. Went with one of the aftermarket pieces.

So I changed that today and went for a test drive. Seemed greatly improved. Still heard a little noise at times if I was listening for it. Got home and popped the hood while the car was still running. Very light taps on the gas (just enough to bring it up to ~ 1100-1500 rpms) I could hear a bit of the noise again. Got out of the car and noticed a buzz/rattle coming from what seemed to be the oil filter housing. Shut the car off and went to open the filter housing. Hmmm. That seemed to take considerably more force than it should. :\ As I the filter was loosened, I suddenly had oil gush out. :\ And then I lifted off the cap and the filter stayed in the housing...along with the center "spike" from the cap. WTF? Then I noticed the filter itself looked a bit...twisted. Not severely but the vanes of filter material were more squiggly than any of the dozen or so filters I've changed myself. Quite difficult to remove the spike from the old filter.

Put in a new (Mann) filter - the old one was BMW branded FWIW - after simply snapping the spike back onto the filter cap and so far it seems like all noises are gone. Hopefully it stays that way. I'm hoping that I wasn't hearing noises due to severely restricted oil flow.

Just an odd day's observations.