Okay....this is the weirdest thing I have ever seen.

When I wash the car, or when it rains (Basically, every time the car gets wet), the trunk lid collects water. And when I open the trunk, a pretty substantial stream of water pours from the latch assembly and from the red trunk light.

I have looked and CANNOT find how the water is entering the trunk.

Any ideas???

Help!!

 

I have the same problem and couldn't figure out why.....

 

All we need now is someone to help find the answer.

I have looked at all seams and they appear to be closed. I just don't know how it gets in there.

 

In w209 clks the most common problem is the third brake light cracking and letting in a ton of water in. Can't be fixed, too much body flex. Some people have gone through as many as 3 new lights in 2 years. Not sure if you guys have the third brake light in the trunck lid though, but if you do that would be a good place to start.

 

Check drains along trunk panel lip (along underside below plate) - they may need to be cleaned to allow for proper drainage.

 

Mine is like that since day one and the dealer even had a tech guy going inside the trunk while another person sprayed water outside and they couldn't figure out where the water was going in from. They thought it was the underside of the trunk on both sides and they sealed them but still the same. So now I have basically given up

 

Could it be getting in somewhere along the silver trim and sipping in?

 

The German engineering of the trunk is on a par with the ease of use of the NAV system

 

I had that same problem with my Ex-wife's CLK. Ended up replacing the third brake light.


Oh cool..... I'll check that!! Thanks!!

I don't think that is the problem.

 

I have this too...only happened two times though and I haven't been able to duplicate it (both with washing the car and driving/sitting in heavy rain.

 

It gets even more weird now.....

After having this problem for about three or four months.....the last two times I washed the car, there wasn't any water in the trunk lid. How bizzar

 

here is your problem.. you make think its stupid but the double-sided adhesive tape on the back side of that chrome trim piece on your trunk has separated and allowed water to sneak past.. you can peel it off and try to replace the tape, but I found it easier to just replace the chrome trim since it comes with new adhesive tape already on it and you only have to clean the residue off the trunk lid.. guarantee that's your issue

on the CLS its the chrome trim above the license plate on the trunk lid.
on the CLK its the 3rd brake lamp

I've replaced many of both

 

Hey all, new to the forum, hopped on here for an answer and found this tread, thought I'd bring it back from the dead.

I can confirm that the water in the trunk is seeping in through the small rectangular holes that help seat the chrome highlight strip above the license plate. I removed all the interior lining and poured water from a can all over while looking at the inside with a flashlight, when the trunk is in the up position the water just drips right in through those holes. It wouldn't pour right in quite as easily with the trunk down, but the water is probably getting in at speed depending on the amount of rain present and how much air swirl is back there to help it sneak in.

I just acquired my car, was worried this meant it had been shoddily repaired after an unknown rear-end hit but it looks like the fault was from the factory, which isn't necessarily better.

Is there an trick to removing the strip? I figure I'll start unscrewing stuff tomorrow when it's light out and see what I can find out in order to apply some kind of sealing agent.

 

Well, that was kind of a pain, but here's the repair solution that worked for me. First I tried applying some Honda Bond liquid gasket to the square trim holes I could find, but there are more holes than are readily available. The only way to do it properly is to remove the chrome trim and redo the double-sided adhesive.

Carefully pry (I don't say gently, because you're gonna need a lot of force) the chrome strip away from the trunk by grabbing it near the handle and pulling outward. I used some wooden shims to keep the trim from just snapping back into place.

Once you've got a big enough gap, use a razor knife to CAREFULLY slice the double-sided adhesive that MB used to affix the trim. I started on the right and side, prying as necessary while i cut. Take care not to bend the chrome trim too far on the ends, it's weakest in the final 8 inches or so where it doesn't have an L shape as viewed in profile, and you could bend or snap the plastic underneath.

As you get towards the middle, you'll have to start using the knife from the top as the L-shape prevents you from cutting at the bottom. just take your time, pry the strip away and cut bit by bit. You also have to move the knife whenever you encounter one of the little tabs that are the source of the problem, they go into the leaky trunk holes.

Once you get the last of the adhesive cut, the chrome trim should come free. Congratulations, now you have a horribly sticky mess on the back of the trim and on the surface of the trunk. Obviously they used an angry form of double-sided tape, but I'm still disappointed with this construction method. Seems like every single C219 CLS is going to have this leaky trunk problem at some point, double-sided tape isn't a very permanent solution to anything.

I alternated between laquor thinner and acetone to get rid of the goop from both surfaces, it's a long, tedious, terrible-smelling job that takes a really long time. There might be a better solution out there but I didn't want to damage the finish on the car or the strip. Expect to use most of a roll of paper towel, cause the goop will rapidly foul up a clean towel, and you don't want to waste more time just spreading the post-solvent slime all over the place.

With both surfaces clean, I used some 3M outdoor mounting tape (the grey double-sided stuff), carefully cutting it to shape to match the mounting points. Folding smaller squares in half and cutting out holes in the middle, I made little tab-sized seals for all the tabs that go to the trunk to ensure they're watertight.

Finally, I applied a layer of Honda Bond liquid gasket to each of the trunk holes BEFORE re-attaching the chrome strip, in the hopes that the gasket will further seal the weak point on this design. The end result looks just like it did before, and the inside of the trunklid has been bone dry through several Florida storms.

 

Hey Skig,
Took me awhile to find your post, but I remembered it from before - and just filed it in the brain pan and decided to tackle the job later. Well, now I'm going rogue, and murdering out the CLS, and need to pull that damn plastic thing off to paint it. I'm going to do your treatment as well, 'cause I'm tired of the leak. Any enlightenment on easier ways to do this thing? (Now that you've had a few months to think about it ?

 

Had the same issue. The carpeting on the trunk lid was always wet.
It was actually 2 things.
The trunk rubber beading was a bit flattened so water was seeping ever so slightly past it.
This also made no difference.
The problem for me, at least was, when i had taken off the chrome strip trim above the license plate to fit my backup camera, the double sided sticky tape was not fully covering the edge.
As a result water was coming in from the tabs that hold the strip to the metal.
So took it off (it is super hard to pry off the old tape, so don't bend the strip), cleaned it, put new double sided tape from one end to the other, especially around the tabs.
No more leaks or a mouldy smelling trunk