Em Bee Lover

I live in a clime where the temps wildly ride up and down. I can go three weeks w/o using a/c and then need to. After a couple weeks of no use, when turning to a/c, there is a distinct smell of "stagnant water or musty basement" coming out the vents. Anyone else have this?

When a/c is used often, it is basically not an issue. But, the smell/odor is distracting, to say the least. Not foul "sewage" or similar, but "foul".

A/C and open sunroof minimizes, but the smell seems to be due to water residing somewhere and not being eliminated.

Anyone else experience this?

Any advice appreciated.

Thanks.

IDriveAnM5

Have you had your cabin air filters changed recently? I change mine at the recommended intervals, and I will also go long periods without running the air conditioner. But, I have never had any odors come out of my vents. Still smells like a Mercedes-Benz!! :-)

emilner

Change your a/c filters to start with, that stopped the musty oder coming from my vents. I would also not shut off the a/c compressor (if you can even do that on an S). Many cars you can shut off the compressor to save on gas. The problem is the compressor not only cools air but also removes moisture...

RoundTheBenz

I just purchased an 07 221 and have the same issue. I also had the same on a previous vehicle (220). First one was taken care of under warranty, new vehicle is in the shop now getting done. Will let you know if warranty covers that also.

BootyHunter57

mine has a weird smell aswell as soon as I turn on the AC
where are the cabin filters located?

Corsa9000

You might have leaves or something obstructing water drainage. Check as much as you can on your own otherwise a dealer visit might be required.

Em Bee Lover

Thanks for jumping on this. I thought maybe I was being "picky". The bottom feeder part of me uses the old "econ" setting, due to perceived mileage drain of the compressor running. Thus, that may be a factore. I strive for current maintenance, so filters have been changed according to schedule. I haven't checked for blockages. If anyone has experienced this and done a specific fix, pls. fire away.

JonMBZ

You probably need the a/c system disinfected the dealer can shoot foam through the system to clean it out. Also change the combination filter.

BootyHunter57

Where would the combination filter be located? Just to know of course

emilner

I would recommend you never run the car with the compressor turned off for an extended period. That will certainly cause a musty smell in no time. Next thing you know you are going to tell us you put regular in it

The A/C cabin filters are located under the glove box. You need to remove the panel located below the box (it is held in with three screws) then slide the clips holding the airbox together and the filters will pull down. It takes 7-8 minutes...

Em Bee Lover

I get 55 octane at the local farmers co-op? What do you mean, "regular"?

Honestly, I was told years ago by a tech, as I have driven Benz since '89, use the "econ", as it's a mileage drain (2-4 in city; why waste if not relevant/AC needed?).

The odor issue was not there in my S430 using econ. But, I will accept your advice.

Thanks, mostly, for indicating the cabin filter location and r/r time. I don't mess with mntce. as I have a tech do it when scheduled.

Regardless, I love the forum and appreciate your input.

nitinopp

Had to get the filters replaced and have a UV treatment.

S5502007

I had the exact same issue with mine and changed the AC and cabin filters...the smell never came back.

RoundTheBenz

I can confirm that the whole system was disinfected and it was covered under warranty. Now no more smelling of old socks! Hope you get the same experience at your dealer.