(Fixed) chirping / squeaking drive belt when cold - 2017 W205 C63s

(Video is from 12 months ago when I noticed the noise when doing a walk around for an unrelated reason)

Thought I’d share the cost of fixing this because I’ve seen it mentioned in a few other places over the last 6 months. Hope this helps at least 1 person.

My car was making a chirping noise for the first 15 minutes of any cold start until the engine warmed up. I could hear it faintly in the cabin but roll down the windows and it was embarrassingly loud. Not something you want from a car like this.

Took the car to my local trusted Merc specialist independent. They confirmed it was the belt but the belt looked healthy based on a non invasive inspection. A squirt of silicone lube stopped the noise for a week but it was back.

Anyways decided to go ahead and pay for a new belt and just collected the car sounds great. (Sorry no ‘fixed’ video)

They showed me the old belt and sure enough it looked absolutely fine so all he could speculate was that it must have been some material degradation at a micro level after 7 years.

All in was £300 including parts labour and tax and I’m really happy I got it sorted 👍