W204 Noisy passenger air vent

[Deadl1ft]

Hi all,

I couldn't find anything that quite matched my issue so here we go... W204 coupe, 2012... with a really fecking annoying noisy whistly whiny passenger air vent!!! At low fan speed (1/2) it's quiet, 3 it will happen... going over a bump can start it off, any fan speed above 3 it will be constant. If I have the air con on it will pretty much be constant. Has anyone come across this or got any suggestions on what could be going on?

Regards

D

 

[FlorinM]

On my w204 coupe I get whistly noise from my air vents only if I close 2 of the 4 vents and then turn the fan over 3-4.

I get no annoying noise if all 4 vents are open, even at full blast.

 

[st13phil]

Check that the cabin filter is properly installed.

 

[mersum1es]

Freezer stuff low in AC system?

 

[MrGreedy]

I used to get this on an older car with no cabin filter. Occasionally, some bits of a leaf might drop through the scuttle panel and a bit would getting into the HVAC system and usually create a whistling in the vent in the centre (nearest to the point of entry of the bits of leaf).

as per post above, if cabin filter isn’t fitted correctly (or missing ) maybe you’re getting some debris in the vent?

 

[st13phil]

Occasionally, some bits of a leaf might drop through the scuttle panel and a bit would getting into the HVAC system and usually create a whistling in the vent

That's exactly what happened to my W204 and the leaf had been trapped in the cabin filter aperture when the filter had been changed.

 

[Deadl1ft]

Check that the cabin filter is properly installed.

I will look thanks

 

[Deadl1ft]

Freezer stuff low in AC system?

No, only had it topped up a few weeks ago. Thanks for the reply though

 

[Deadl1ft]

I used to get this on an older car with no cabin filter. Occasionally, some bits of a leaf might drop through the scuttle panel and a bit would getting into the HVAC system and usually create a whistling in the vent in the centre (nearest to the point of entry of the bits of leaf).

as per post above, if cabin filter isn’t fitted correctly (or missing ) maybe you’re getting some debris in the vent?

I'll check thanks. Its definitely there because a trusted garage serviced for me a few weeks ago. But I'll checks the fit

 

[Paulo1967]

I have exactly the same on my 2008 W211. I agree, I suspect it's a trapped leaf or something, I'll investigate at the weekend.

 

[fourwheels]

You’ve all got me wondering now.
I’ve been complaining of the sound of rushing air somewhere near the front nearside of dashboard/windscreen since a B Service last year.
A return visit to the dealer resulted only in a diagnostic charge and advice it needs replacement (acoustiic) glass - rubbish.
I wonder if it is a leaf or something they allowed to get trapped when they changed the filter.

 

[MrGreedy]

Eventually, it desicates so much and starts to fracture, and blows out of the vent into your eye at an inopportune moment.
You crash. But at least in the moments before, the whistling has stopped