Different suppliers for most components with obviously different tolerances, and a design intolerant of the variances. This isn't just a U.S. issue, it's talked about being a problem on the German forums.

I bet some engineers knew this would be an issue. Might be like the w204, they had a known design flaw with mirrors and a couple years later offered a fix (new mirrors and seals...not covered by warranty). I know it was several thousand to 'update the design' from what most would call a flaw...on their top selling car.

So I'm new here and trying to come up to speed. I agree that IF these are all US-only problems, they are likely not a design flaws. However, it's equally unlikely that they are just due to "bad QA". Too many great German and Japanese branded automobiles are coming out of US factories (and being exported around the world, including to Germany). So something's going on in the US that is not happening elsewhere.

I've personally driven 4 c300's. Three that I test drove. And the one that I own.
I remember telling my gf how quite the cabine was after our first test drive. I hit speeds of up to 120kmh. No wind noise. On the second test drive at a different dealer I only went up to 100kmh. Still no wind noise. 3rd test drive again different and final dealer. I didn't jump on the highway so It doesn't really count.
With my car I've hit some decent speeds and I do hear some wind noise. Nothing to complain about. You would expect to hear some wind at those speeds. I'm on Bluetooth most of the time and never got a complain. It's quiter then my Infiniti.
From my experience it's not a design flaw. I believe It's an assembly or parts flaw. Hopefully they get this fixed ASAP. I could only imagine some of the
frustration some of you are feeling.

without trying to sound like a badge ***** I think too many people on this board like to jump on the bandwagon that it is a design flaw because of incompetent dealer experience

I think they're annoyed because the car has a fault or does not meet with their expectations of the brand, not because of a dealer experience. This is build related not dealer related. Something somewhere is either badly designed or has a fault, in any event what owners want is a resolution. The fact is, MB are producing cars with what owners feel is unexpected of the brand and their experiences. While I respect the fact you feel the brand can do no wrong. No one is perfect. Every manufacturer has build or design issues now and then, despite all their efforts.

You have good reason to be concerned. I mean, let's call it what it is, take brand loyalty out of it, and take out how great the car is with upgraded interior and exterior, and the car is leaving a lot to be desired in build quality. It's not even old enough to speak on reliability.

I have one on lease. I couldn't bring myself to buy it, as too half baked.
My dealer, admittedly a friend who manages, said wind issue a huge one. They returned my first car to factory. Replacement they out in acoustic glass (which took a lot of arm twisting to have MBUSA get dealer the acoustic glass from Germany). The glass makes a huge difference. It should be standard, and all cars made without replaced with it. Not Lexus quiet, but not the diseaster this car was with wind noise.

Now we just need a bunch of new firmware to fix trans, Comand, steering.....

Maniac, you've got it completely. I'm the perfect conquest customer for MB, being a long customer of the three other German luxury brands. I picked-up on the wind problem as a potential deal breaker issue in a test drive last October, well before it became the topic of every third post on this forum. But I thought at the time that, whatever the problem was, Merc would handle it. Now, what's most disappointing is not that it hasn't been fixed, but that its existence is being denied. That leads one to speculate that the cause is not easily remedied. And with stonewalling from the manufacturer, speculation runs wild. As the saying goes - it's not the crime, it's the coverup!

JD Powers' 2015 Initial Quality Study was just released. Merc's ranking dropped from 14th place to 15th place. Their average defects per 100 vehicles sold were 111, compared to an industry average of 112. So the premium brand essentially has average quality. Sad.


Fwiw, BMW rose from 8th place to 6th place with an average of 99 defects, and Porsche remained at the top with 80.

That is exactly waht MBUSA told me - the wind noise is a result of W205 "design characteristics". The rep claimed to own one and admitted his car has the same wind noise. MB messed up. My dealer told me this is not the first model MB has designed wind noise into. Then you have owners claiming they have no wind noise. Who is full of BS? The owners or MB? I choose MB.

perhaps more accurate way of putting it is, do you believe the rep behind the desk or owners ? then the answer would be different