2012 X3 28i. I started to hear an intermittent screeching noise from the belt. I thought maybe its the belt maybe its the tensioner pulley. I replaced them both.
The noise is still here. Its only present after the car is warmed up but only on the initial start. So if I cold start the car its fine and I drive to the store. When I come back from grocery shopping and start it again it starts to screech like the video below. Turning the AC on or off doesn't do anything. If I turn the car off and turn it back on again the noise goes away until I drive somewhere else and turn it off for a few mins. Then the next start it will have the noise till I start the car and turn it off again.
The only other thing the belt runs is the alternator or AC compressor. Since turning the AC compressor on and off didn't do much I'm thinking alternator? All the pulleys spin freely by hand and don't make any noise.
https://youtube.com/shorts/L6JwUCftjhs?feature=share