[2012e70]

I recently purchased a 2011 E92 328i with its valve cover gasket and spark plugs recently changed. The car has 250,000 km and runs fine, other than a grinding sound that occurs only at idle. The sound disappears after 1k rpms and doesn't seem to affect driving at all. There are no cels or leaks. The only potential cause I can predict is that it may have something to do with the AC compressor, which may be on its way out. Do you have any idea what this sound could mean?

[GoRomeo]

Originally Posted by 2012e70

I recently purchased a 2011 E92 328i with its valve cover gasket and spark plugs recently changed. The car has 250,000 km and runs fine, other than a grinding sound that occurs only at idle. The sound disappears after 1k rpms and doesn't seem to affect driving at all. There are no cels or leaks. The only potential cause I can predict is that it may have something to do with the AC compressor, which may be on its way out. Do you have any idea what this sound could mean?


https://youtu.be/4uIqhnQJaTk

A Belt pulley? Remove belt from tensioner and pulleys. Remove the belt just a bit and turn the pulleys manually see if you hear the noise. Check belt tensioner while you are there.

[lookalikehuuh]

I actually had a somewhat similar noise which turned out to be the bearing inside my alternator. Take a large screwdriver and place one end on a metal part at the top of the alternator then the other side to your ear and see if the noise amplifies into your ear. Move it around to different components and see where the sound amplifies the most, that will be your failed component.

That should give you an idea of where the noise is coming from.