Hi MBWorld members,

I've searched the forums and the wider web and haven't really found anyone experiencing the same issue I am, so hope you may have some insight here.

I have a 2011 E350 4MATIC sedan, and I'm having issues with heavy condensation forming large droplets inside the car, specifically on the black suede material inside the left rear window right up right up against the B-pillar. Worse, it's starting to form some mold or mildew on that suede material.

My assumption was that there was a leak somewhere, but I've had the sunroof drains cleaned out, re-fitted, clamped, and tested, and I can confirm there seems to be no water getting in anywhere around the left rear door that I can find. There's no heavy moisture or indications it's leaking down through the window or anything. I live in a fairly humid area (Pacific Northwest), and this is most commonly happening after rainfall. Pretty much at my wit's end here.

Any suggestions or insight y'all have here would be amazing!


Heavy condensation- the white spot on the suede is from me using a solution to try and kill the mold/mildew that had formed there. Used a scrubber that was a bit too abrasive for the surface unfortunately.

 

search for "sunroof leaking" in your case it is the B-pillar seam leaking under roof trim.

Use shipping tape to cover your roof trim from front to back... then let it rain
👍

 

Appreciate you! Will give it a shot this weekend and report back. $2k later I’d honestly be both relieved and a little annoyed it’s that simple 😅

 

The 5¢ shipping tape will have you covered until you have time to deal with this joke.


> How to halt leaky roof game: :

Realize where it is leaking today (front; back; both)

use a good 3M sealer made-in-China for peanuts

Pull the roof plastic trim to expose failed sealant

Try to spot leaking area today.
if not located patch front to back

Regardless, it will leak there soon.

Stay dry! Rear leaks not to bad on left side.

If you live in a wet climate area unlike California consider getting yourself a MBWORLD forum ID - It will come in handy with :

• F/R bumper connectors,
• leaky headlights,
• plus everything we don't know yet

"MBWorld delivers when your MB needs attention!" hopefully

 

Check under exterior drip rail (10), revisit body edge guard (150), door seal (200), and window sealing (100/160). B-pillar removal @ 2:34 in video. If you need part #s provide VIN.

 

VIN WDDHF8HB8BA358276.

Pulled up #10, and don't see any obvious points of failure in the seam - poured water in and couldn't see it doing anything it wasn't supposed to, just drained along the rails as intended.

Pulled #150, no obvious leaks anywhere there, and on water testing couldn't see water getting into the body anywhere around #100 (drained as expected around the edge of the door).
Popped up the B-pillar as well and couldn't see any water behind it.
Wasn't sure exactly how to remove #160 (can get to a spot with more tools and whatnot this coming weekend, working remote atm) but on water testing didn't see water getting in through there either.