I have a 1995 E320 with no body rust anywhere. I just noticed this problem. If I park outside in the rain, when I open the trunk, rainwater pours out of the trunk lid where the locking mechanism is. Water seems to pool behind the license plate, then when the lid is vertical, all this water pours onto your head while you're looking in the trunk.

I cannot for the life of me figure out where the water is getting in and how it is collecting inside the trunk lid by the license plate. Has anyone else encountered this???

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Remember, Bad Decisions Make For Good Stories

First I would check that the rain gasket around the trunk near the window is not full of leaves and compost. It is a simple design and works well - when the channels are clear of debris.

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles

I placed paper towels around the trunk, closed the trunk lid, then sprayed all around with the garden hose. Then opened the trunk and saw that water was entering from around the rubber trunk seal.

Also you can stick a piece of paper at various points of the rubber seal, close the trunk lid, then see if the paper will slide (gap between rubber and lid) or is firmly gripped by the rubber seal (paper will not slide).

I found a replacement rubber seal at Amazon.com. Also used 3M weatherstrip adhesive.

That solved most of the leaking. There remained a bit more leaking which I traced to a rear light assembly which was not attached properly - missing nuts - and part of the gasket was twisted so it was not in place like it should be.

For that I just totally removed the tail light assembly, placed the gasket on properly, bought some more nuts, then fastened on properly.

No more leaks!

it also might be coming from the moulding that holds the license plate lights. I check mine yesterday on my '95 E300 and it appears to have a gasket there? look for water stains on the liner under the truck lid too

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles

P.S. Water gets in the trunk lid by the sun (heat) and condensation. (From water in the trunk due to a leak.)

There was a rubber stopper I removed on the rear left lowest portion of the trunk lid - water drained out. I also drilled a same size hole on the opposite side, then painted it so it would not rust.

Yes, I've had that problem. I replaced the trunk seal but it still leaked. Mine was two spots which I only found by lying in the trunk with a torch whilst my wife ran the hose over it.

First leak was the outside part of the electric antenna seal was missing and the second was the rubber seal that goes around the trunk button. It gets large with age and no longer seals.

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1995 E300 Diesel