risotto

I’m trying to troubleshoot a noise on my 2010 CLS550 that sounds a bit like a belt rubbing on plastic (the low frequency kind of hum), but at least from what I could tell by looking around the compartment, wasn’t actually the case. No perceivable smells of any kind are present either, such as burnt plastic or rubber. From inside the cabin, it sounds like it is coming from the left front side of the car.

This usually occurs when the engine’s weight shifts forward, such as when braking hard. The noise remains for a significant while and is most pronounced at 800rpm. It does vary in frequency when the rpms are pushed, even in neutral, so it’s not related to the wheel moving.

Anything in particular I could check to troubleshoot this? Any common issues? This is a 2010 model.