[Edu76]

Hey guys. I have been trying to diagnose an intermittent cold start issue and after showing attached to a mechanic was advised that the way the engine is operating/sounding he would like to take the fan belt off to see if the noise changes. He is thinking it could be an alternator or AC compressor. He also says that timing belt could also be going based on the noise.
Would appreciate some advise based on the attached two video links. At this point the intermittent cold start issue it’s not a big deal.

2015 535XI
102000 miles

Pulleys and belt were changed at 60000 miles
Right now I’m not having any battery issues and voltage is at 13.9 when car is running. I’m handy and I can pull the belt out but wanted to ask here first before I started anything crazy.

Thanks in advance for your help.

https://youtu.be/PzX8rMl0P6w?si=gdPdr9YII8gL6_T3


https://youtu.be/mXKex30-CSc?si=zyWMZDO58hlLAHZ4

[calswan7145]

Hard to hear but it does kinda sound like a pulley, possible theres an idler or the tensioner bearing going out. I’d pull the belt yourself and spin all the idlers and tensioner pulley and check for play. Fan is electric, timing is chain. If chain is stretched it’ll sound like a metallic rattle.

[ChiltiCoatl89]

very hard to tell, Does your A/C kick on when you start? Please confirm it is off when you start, and then after it drops in idle to 800 after a little warm, then kick on the a/c

[StradaRedlands]

It sounded like normal clatter to me, but that doesn't mean there isn't something else there. How old is the belt and tensioner? You might just want to replace those while you're in there. Also just throwing this out there, but maybe the timing chain tensioner?

https://www.fcpeuro.com/products/bmw...-11317584723oe