W202 trunk leak solved!

[mpolli]

This should apply to C230, C280, maybe others.

I had a persistent leak where I would find water in the lowest spots in the rear corners of the trunk, below the tail lights. I searched with a flashlight for any water trails but could not find anything definitive. I removed the tail light assembly and thought that might be the problem. I cleaned up the gasket very well but it didn't help. It still leaked.

Next I stripped the trunk completely so I could see everywhere. Then I closed the trunk and made a rain storm with my garden hose, for about a minute or 2.

At first I still could not see anything, but then I spied a little trail from the middle area nearer to the latch. Closer inspection showed the gasket was all wet where it attached to the body. I pulled it off the body seam and it was all wet and slimy. It appears the factory uses some kind of white sealant, and it must be from their biodegradeable wire supplier since it was totally decomposed into white goop/slime and not sealing anymore. It appeared that water was making the trip under one side, around the body lip and down the other side, maybe through capillary action.

I cleaned the gasket which was quite a bit of work. Then I laid in a bead of clear silcone sealant since that is what I had laying around. Pressed it back on.

It has rained a lot since then and trunk is nice and dry.

I had searched a lot and found almost no other complaints from others with this model so it may be it just cant handle the Seattle water toture weather we have. Just the other day a guy at work who just moved here from Texas said very matter of factly "This must be what nuclear winter would be like."

[Hirnbeiss]

I don't think the factory uses anything there. It could have been a prior owner or body repair thing.