SnakeDoctor

I owned the 2010 E350 sedan, and the funky A/C smell would show up after a while. Once the scheduled maintenance came around and the filter was changed, it went away. After another while, the smell would return. My guess is it would go anywhere from 10-15K miles before starting to smell bad.

Well, less than 4K into my 2014 E550 Coupe, the smell is already present. Color me disappointed. Of all the cars I've had, only the Mercedes cars have had this problem.

NCBob

21,000 miles here. Never any smell.
Saw a segment on TV that mildew collects in the condenser under the dash area causing the odor.
There is a spray you can buy to kill the mildew. Forgot the name. Don't think it is the filter.

axhoaxho

The smell usually is caused by moisture collecting in some damp areas (e.g. the evaporator) inside the A/C system. That causes mold and mildew, hence the smell.

Since your car is very new, does it happen that sometimes you keep the A/C Recirculation Mode 'ON', especially before shutting off the engine and let the car sit for a while when any moisture was trapped inside?

SnakeDoctor

I rarely run in recirculation mode. The last couple of days, I've tried running the fan on max and turning the AC off for about 10 minutes before I reach my destination. Still smelling. I read that it is just how it is living in the hot humidity of Houston, but I haven't had this issue with any other car I've ever owned.

axhoaxho

Yes, I used to live by the ocean, and many of my cars had the smell in the A/C system over time. Some cars had the smell sooner, some later, all depends.

It is a moisture thing... Hence, I made a habit that before I shut-down the engine, I turned-off the A/C and leave the fan on high (circulation mode off) for a few tens of seconds. That helped.

Or, for the cars equipped with cabin air filter (like the Mercedes), I just change the cabin air filter often. I bought them online, and changed them myself accordingly.

advocado

Hmm... I have an E550 Cabriolet ('14) with 7k miles and it still smells like an American Beauty Rose. SF bay Area, near (but not close) to the ocean.

darrellj48

I live in the very humid mountains of Virginia and drive a 2011 E550 Coupe. I have never had any problem with bad odor in the A/C system though I do sometimes have minor fogging issues with the windshield on the lower passenger side and the passenger window where the air dust is directed toward. Not sure what could be causing your problem but it is possible that you have some kind of mold colonized in the duct work. Same thing happens to home A/C systems in the very humid Chesapeake Bay area.

Kirkster

It's been humid here too and at 4K no smell at all. Get some chemical guys new car smell or leather smell and put the AC in recirculate mode and do a couple of sprays near the footwells. Mine smells new all over again.

SnakeDoctor

Thanks Kirk, I've tried that and it helps some. I'll keep trying. It's not as bad as it was, but I assume it's because I no longer run the system on auto. So it's never really going full blast.