[arkow]

I own a 2012 X3 35i and once in a while when starting the car, it makes this high pitch noise coming from the engine area. Its like a loose belt but 10x louder, any idea what this could be? mechanic says they wont be able to troubleshoot if it doesn't happen all the time.. is it the belt? pulley? tensioner? is there a way to tell somehow?

Thanks

[Scout10]

Get a flashlight, raise the bonnet, have assistant start vehicle, stick
your head in there to listen and look. back to basic first step

[ianfp]

It sounds like it could be the alternator belt. Is it worse if you start the engine with lights on?

[arkow]

It doesn't happen all the time so it's hard to troubleshoot but I was able to get s video of it when it happened. I was thinking to replace the belt, tensioner and pulley to see if that fixes it. I turned AC off but that doesn't change anything. I was told by someone that it could be valve cover, never heard that before..

[arkow]

ok, so i replaced the belt and tensioner with pulley and I was hoping the noise will be gone, NOPE, noise is back and it looks like i need a new valve cover, something to do with crankcase ventilation system (PCV), i just don't understand how a car with 70k miles needs a new valve cover, this is insane, cost is around 2k to replace... and i have seen multiple people posting about this issue, this sounds like a defective part not maintenance or something that should die at that mileage..