Originally Posted by mattbta

Our 2009 C350 had this problem. Multiple trips to the dealer never really fixed it. So far in 2500 miles, the 2012 E350C does not exhibit the behavior, but we're waiting until full blown Dallas summer to make full judgement. Hopefully it is fixed by this model year.

Originally Posted by LaicepsYdobon

Like K-A, I had two W211s before my W212 and MB acknowledged the "stinky A/C" problem of the past generation E-Class. The reason for this was that the discharge hose, the hose where the condensation from the A/C unit exits, was designed to not drain fully but to capture a small amount of discharged water. If this trapped discharge did not evaporate on its own it allowed bacteria to grow and produce mildew at the end of the discharge tube which spread all the way up to the filter. If mildew was present and the A/C unit was turned on it would permeate through the cabin producing a pungent stench but would eventually stop after a few minutes after enough air passed through the system to blow most of the mildew out of the air vents into the cabin (I know; yuck !). This was more prominent in the spring where people's A/Cs were not used all winter and the mildew had enough time to grow. If you only had mild mildew buildup it was enough to run the A/C a few times (for maybe 2-3 days) and have all the mildew out but in some more severe cases a trip to the dealer would be necessary if you were not handy with a can of fungicide. On the W211 E-Class under the glove box (or maybe through the glove box ?) would be the access point to get into the A/C system and the dealer would replace the old filter for the A/C unit there and also spray some anti-fungal foam into the tubes to kill all mildew spores leaving you with a fresh smelling A/C unit.

After receiving enough complaints MB redesigned the A/C discharge hose on the W212 and currently extracted water does not get trapped inside the hose but drains out of the car almost immediately. While I'm not saying it is impossible to get mildew in the W212's air vents it certainly is much harder then it was to get it on the W211. Search around on YouTube and you will see that every manufacturer is affected by this at some point or another. YouTube will also have videos to show you how to spray the fungicide on your particular model of car. The easiest way to prevent mildew buildup in your A/C unit is to run some warm, dry air about once a week through it to keep those air pipes dry.

Originally Posted by amaycg

Take advantage of your Audi discounts and get the new A6! Beats the E in a some areas, specifically technology and exterior design
I've had the AC mildew smell on all my previous and current MB's

Originally Posted by veerodder

I considered the 2012 A6, and have drove one pleny of times. The residuals on the new A6 Prestige are not very good. The E Class would save me a lot of money, even with my employee discount. I'm also looking at a S4, and the 2013 A4/S4s are getting a facelift, so I'd be stuck with the old look. Which I don't want. Greenway Mercedes and Sugarland Mercedes are both giving me employee pricing, even though I work for a competitor. One of the perks of being in the car industry..

Originally Posted by acela11

that seems to be good advice, did you see the suggestion about mothballs for increased octane and better fuel mileage?

Originally Posted by paulkchoi

Thanks PH, I will try that.