This is my first post in this community so appreciate any pointers i've missed in advance.

**TL;DR:** My Mercedes CLA has a rattling noise from the passenger vent area since March 2025. Dealer has had the car for 6 months, no fix, no real updates.

I’m pretty disappointed with Mercedes UK service so far (not naming branches). Over \~18 months with multiple visits which introduced new damages to my car, that only got fixed after endless back-and-forth. The current and latest issue has dragged on for \~6 months: I’m in a courtesy car with no dates, timelines, or meaningful updates. I have to chase both the complaints team and the dealership, and the reply is always the same: “we’re looking into it.”

The issue, as you've seen on the video is a rattle noise coming from the passenger's vent, noticable when driving above 30mph, 50+mph is when you can really hear it and on this video I'm doing 70mph to record. It doesn't matter if you have the A/C or just fans on, it's happening even without airflow coming in the cabin.

This started when I took the car to the garage for it's second annual service (eg. they've burnt the driver's speaker during the first service which took a year to fix alongside a cut door seal, etc.). While picking up the car and driving home, I heard the noise and returned the car back to the garage to notify the team.

  
Initially MBUK didn't want to accept that it's a fault. They even tried telling me that "you're not meant to go above 70mph" so therefore it's not covered under warranty - I pushed back of course. They've then accepted to cover the repair under new car warranty but since then (March 2025), they're running out of ideas while I only had probably three meaningful updates - a specialist team had seen the car.

They've checked the scuttle panel screws, they've refitted the windshield, they've put some sort of lubrication & foam sheets all around the engine's moving bits (awful) and lastly they've tried to reseal the A-pillar on the passenger side but zero luck.

What I've seen online and have suggested to the workshop (not sure if they've followed):

* Headlights / Wipers / Glovebox / Speaker rattle check.
* Engine mounting bolts / Bearings / Silent blocks failing.
* Check the little gear within the vent that opens/closes it.

The noise identical to a few posts here:

* [https://www.reddit.com/r/mercedes\_benz/comments/us6lid/mercedes\_light\_crackling\_noise\_sound\_coming\_from/](https://www.reddit.com/r/mercedes_benz/comments/us6lid/mercedes_light_crackling_noise_sound_coming_from/)
* [https://www.reddit.com/r/mercedes\_benz/comments/1j3nzee/does\_anyone\_know\_what\_the\_rattle\_noise\_might\_be/](https://www.reddit.com/r/mercedes_benz/comments/1j3nzee/does_anyone_know_what_the_rattle_noise_might_be/)

Funny thing is that it's not just my car, I'm CCd in a chain of a few other CLAs having the same issue. My car has effectively been in the garage for the past 6 months, with minimal updates from the dealer, waiting for a fix.

Has anyone here experienced this rattle? And if so, what fixed it? Any sort of ideas are highly appreciated.

Thank you!

CLA 220d C118 - Passenger vent rattle noise