Popping / knocking noise inside dash

[Vulture]

Hi everyone!

I've got a popping / knocking noise coming from inside the car. It only happens when going over bumps and the noise is really loud.

I spent all day yesterday dropping the headliner and tightening all the sunroof bolts, but that didn't work.
I 'm pretty sure the noise is coming from behind the dash (although, I said that about the sunroof too!) on the passenger side, so I've removed the glove box and think it's coming right at the back near the firewall, just where the vents are for the windscreen.

Just wondering if anyone has had an issue like this before or has any workshop guides for that area of the car?

Also, any suggestions of where to check would be appreciated!

(I've got a 2015 W205 C-Class)

Thanks!

 

[Smart320]

Top of suspension, say broken spring or top mounting plate or loose shock absorber at the top , not an expert but wonder if going over bumps is the clue. Am sure forum members with more technical expertise will offer more help

 

[saff]

I agree with Smart320. Noises like this can travel through the structure and can sometimes sound miles away from the true source. Anti-roll bar drop links/bushes can have this effect when they give up.

 

[Vulture]

Thanks for the suggestions! I've jacked the car up today and there is no play in the wheels and all the suspension parts look ok with no play in them.
I've got it booked in to have it looked at on Tuesday, fingers crossed they can find the source of the noise!

 

[Vulture]

Just thought I'd update this, took the car to Mercedes and they found the issue. It was a loose bolt on the crossmember.