dtd

My MY2017 C300 has a stinky smell in the cabin after the AC is off. I just got a 20K miles service at the dealer. What could be the problem? Your input is greatly appreciated.

C43Flyby

I was getting the same thing in my 43. I think it has to do with condensation from the cold air sitting in the vents after being shut off. Usually, I blow the fan at max with the A/C off for about 60 seconds as I'm approaching my destination and that seems to pretty much stop it from happening.

dtd

Thank you very C43Flyby. I will try to see what happens. By the way, should the dealer fix it since, the car is still under warranty.

C43Flyby

Hard to say. If it's what I've experienced there isn't much they can do. If it's something else though due to something they did, then absolutely. I would try blowing max fan for a bit before you get where you're going and see if that corrects first.

dtd

Will do.Thanks,

chrisdean

You shouldn't be turning the a/c off, just adjust the temperature to your liking and that way you will keep the system maintained and avoid any seals drying out and leaking.

Popoff

Not so.

Need to turn off the AC (not the fan) a few minutes before shutting down to evaporate the condensation in the system that causes the smell. Another trick, in addition to turning the compressor off, is to turn the heat up as high as it will go for a few minutes. This old trick can also get rid of the smell if it already exists.

dtd

Thank you all of you . I will try.

ygmn

Can of WURTH AC cleaner spray into vents and while system running into inside air intake...

Kills all the nasties

fabbrisd1

My cent's - at 20K B Service - replacement cabin filter is "recommended" - check your Service Invoice to see if that was done - and review in your head what your Service Advisor asked/told you about that.

If you didn't report this issue before your 20K/B Service - and you didn't approve Cabin Filter replacement - then you have some good advice above so far - you can get your Cabin Filter done next service - recommended to use Auto set at comfortable temp for you - use Max Cool for max 10 min then switch back to Auto - don't leave your temp on manual too-low/too-long or that adds "frosting" to your evaporator and when you shut down the car that frost melts leaving evaporator box very wet/damp and leads to moldy/old-gym-shoe smell.

If you get to be in the land of the old-gym-shoe-smell - leave car running - windows up - max heat for 20 min will scorch that sh*t out.

Wurth or Einzett/Nextzett iboth are good stuff for system "cleaning" - and frankly as good as the MB dealer "bacterial cleaning" which they charge arm/leg for.

MariTheBoss

Fabbrisd1 is correct; set the air to auto at your desired temperature. This has been discussed at length, and of you search the forum there are some substantial explanations as to why the auto setting removes and prevents the smell. Replacing the cabin filter helped for a few days, as did an a/c treatment, but the smell returned. Once I set the air to auto at 67-72, the smell dissipated and has not come back in over a year.

CJG

In the W204's there is a drip line that runs from the evaporator pan to the underside of the car. When ice melt/condensation drips off the evaporator coils it would allow the liquid to drain. This drain would plug on occasion and cause the smell.
I'm guessing the W205's also have a similar drain. Perhaps it's plugged.

benzw205

hello,

so it is really useful to stop aircon and only let the fan on ?

thank you.

benzw205

interesting, I did not know about the heater. thanks.

W205_Merc

After you use the air conditioning and are approaching your end destination.. a few minutes prior to turning the engine off... turn the AC OFF and let the fan run. do this with the temperature at a higher setting from where you were using your AC. When you do this it helps evaporate the condensation that remains in the air vents

I've had this same issue and the smell is ****ing gross. Try using FrigiFRESH or FrigiCLEAN.. its helped me out a lot.

benzw205

I really doubt that setting the system to AUTO would be better than blowing with air conditioning turned off for 60 seconds, can you explain please ?

dtd

Hi benzw205,
I don't smell anything anymore. I did try what everybody suggested here. I think it works. My wife drives the car most of the time. I only drive from time to time during the weekend. The car has been in B service at the begiining of June, and the dealer changed the in cabin filter , that could be the reason of the bad smell. Before that, there was not bad smell after AC was off. I will monitor and let you know.

TexasBenzBandit

Did you cut one? I doubt that's it. OK then while you are at it, you should change your Cabin Air Filter if you haven't before (just ordered one today) and I wasn't aware of this until today, but lot's of good reviews on this stuff (or use similar) . When you do the Cabin Filter, there is a connection next to it with the glove box cover removed and you can run the hose up through there and try the foam. Apparently, it cleans and kills bacteria. I'm in a Hot Climate so we get more of the bacteria that causes things to stink.

dtd

The cabin filter was changed at the B service ( 20K miles).