I hear that the trunks leaked on the 500 SEC and my 84 does. it creates a puddle on the passenger side and it soaked my camera... how do I stop this and where does the water come from and don't say rain LOL

No experience with your particular year/model, but most leaks come from a bad rear window seal, either the rubber or rust-out in the lip/channel at the lower edge or corners, or, and this is far more likely, the rear light housing gaskets, where the plastic assembly joins the body.
If it's the light housing, just unbolt the whole thing, clean it all up, and use silicone sealant around the edges where the gasket is (or was). Unlikely, but it could be a torn or worn out trunk seal rubber, easily checked visually.
Hard to do in winter, but someone inside the trunk with another spraying water all over outside might reveal the leak, if it's coming from the window glass seal or the rubber lid seal.

__________________
1986 560SL
2002 Toyota Camry
1993 Lexus

The rear window is a good possibility. If the glass is showing delamination and you have rust on the body piece in the trunk immediately below the rear window, that's your culprit. Mine leaks. I know.

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

This is what I have been reading, it happens when the car is stationary so i figure its a window seal, but I will check trunk seal first, the car is in great shape and I can't take a chance on ruining it.

I would not rule out the antenna seal (if the coupe has the antenna on the back like the sedan). I had a 1985 380SE sedan. When it would rain, the trunk and believe it or not, the right rear passenger floor would pool up with water. Upon someones recommendation, I replaced the antenna seal and the water never came back. My floor was as dry as a desert in the middle of summer. Trunk was dry as well. I have another W126 now and I am getting a little water in the trunk, but again, I think its the antenna seal, because there is NO rust around the rear window.

Ya my 420 SEL was bad for that it was nuts, also the roof seal and bad drain holes. I should change my seal on my roof and the antenna. the ass end of that car is the same as the SEL. This car is pimo and I don't want to frig it up.
I read the DIY on the rear window seal repair and I am not looking forward to that. I had a ***** of a time changing my antenna seal last time, any tips?

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Well I am not much of a DIY'er - cant seem to do anything on my own, but I was able to easily change the antenna on my 85' 380SE by myself. Thats not saying I will be able to do it easy on my current W126.

I guess it varies from car to car.

The trunk leak was traced from the rear Star and chrome section .i reinstalled these with automotive silcon sealant .as yet no leaks at all.
mak

See I changed boot lids and the issue still persisted, I have a feeling its the window or trunk seal... Or Al Queda? we should get 20 SEL and SEC owners together and have a seal changing event and BBQ... err when it's hotter.

Have you replaced the antenna seal? As mentioned, on my old 85' W126, it appeared to be good, but it wasnt. It caused water to get in my trunk and rear passenger floor. I replaced it and my water issue problems went away. Its the easiest thing to replace and cheapest. It may not be your issue, but I would not rule it out.

when I uncover the car in April I will do that, it's worth the $20, I will try everything as the car is worth it, and heck it's 24 yrs old why not

Yeah, hopefully its your problem... but if your luck is like mine, its never nothing easy.

Let us know!

Well I have a 1984 500SEC. Took awhile to find the problem. I used three tubes of sealant(large caulking gun type) before I realized the water still came in.
Take a very close look at the drip moulding. Follow it's path from the front windshield to the rear window.
In my case as the moulding approached the base of the passenger rear window the rubber material had shrunk over the years just enough to let water trickle in.
I found this by carefully looking for the slightest dry water stains on the walls inside the trunk. I used a very bright flashlight at dusk so my eyes were not fooled by the daylight. I saw the faintest water mark way up beyond the filler tube. Had someone else spray water on the cars top, and sure enough, trickle trickle.
Resealed the drip moulding with more sealant. No more sneaky leaky.

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Selling used Mercedes parts on Ebay...always changing...
cdplayer51 take a look!
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I should try that... A full seal replacement is the best option if you are paranoid, I will change the sun roof seal too. Is the roof seal hard to change?

The sun roof seal replacement on my wagon was a trying experience. It's a manual one. I haven't tried it on a power sunroof, so I don't know if that would be harder or not. There's a lot to be said for having the knowledge that all of your seals are brand new.

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles