Ever since I have owned my 83 300SD it has had a water leak around the windshield/sunfoor area. I made up my mind to fix it. It needed a windshield so I had a new one put in and I stayed there and watched them. The windshield was sealed up good. Next rain I had water drip from the rearview mirror area and down both "A" pillars. Last weekend I opened the sunroof and checked all the drains by pouring water around the opened sunroof. All the drains flowed well and none leaked into the car. I closed everything up and I bet I pumped 2,000 gallons of water over, under, and every way you can and did not get a drop of water anywhere. We had a hard rain Saturday night and behold Sunday morning I had water that leaked in the same place. It only seems to leak when the car is parked. It doesn't leak while driving.
If anyone has had this problem, let me know what you came up with.
Thanks,
Rodney

Last Saturday we spent all afternoon trying to locate a similar leak on Mistress's 420SEL. After tearing everything apart without locating the leak, Johnhef discovered a broken pop rivet onder the trim on the passenger side of the windshield. We put some silicon in the hole, reassembled everything, and, voila! it didn't leak at all last night when it rained.

This was not really that easy to see. Maybe you have something similar on yours.

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" 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

I fixed my leak last weekend. It's been bothering me for a year and it took me about 20 mins. to fix. It was dripping down from the rearview mirror (and ending up in the console pocket right below the ashtray) and down both A pillars. There is a gap in the windshield trim at the top of the windshield right in the middle and a little piece of trim that slides, which is supposed to connect the trim so it looks like one piece. Right at that gap I had an area of about 4 inches where that sealant between the metal roof and the window was gone/degraded. I squeezed in as much sealant as I could into that gap (actually I used blue RTV gasket because I didn't have silicone, but it matches my blue paint ). I laid a nice thin bead along that joint and pushed it in with my finger as best I could and then laid another bead and smoothed it out nicely. The nice thing is that I could wipe the excess off with a cloth where as with silicone sealant it tends to stick and make a real mess if you're not careful. Without looking at it, I'm not sure if this sealant would be replaced if you got a new windsheild.
I seems really odd that your car only leaks when parked and when it rains, but not when you pour water all over it.

Thanks, I will take a look at that trim. I still think it is the sunroof somehow.
I was thinking of putting some duct tape all around the sunroof and let it set during the next rain. That would tell me at least where to keep looking. It appears that this has been leaking for a very long time, even before I owned the car, because the corner dash wood below both "A" pillars has seperated.
Thanks for all the help.
Rodney

Ha... the corner wood trim has popped off at my a-pillars too. (I had a bad wheel bearing race that made a bad buzzing vibration which finally popped it off, but it makes sense that the water weakened it first, I hadn't thought of that).