I have a interior water leak problem in my 300D. OK so who doesn't but I figure since this seems like a common problem there should be lots of good advice available. After a rainstorm my rear foot wells are mini ponds and the trunk is also full of water in both side pockets. The front foot well seem to stay dry unless maybe the rears overflow.
Where should I start looking? Is the rear window seal the usual suspect or could it be something as simple as the trunk lid seal?

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Seems the most common spot is actually under/behind the hood hinges...there is a drain that frequently gets clogged and does not get noticed. Next suspect on my list would be rear window seal and sunroof drains.

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

I have noticed quite a bit of debris in the hinge pockets but haven't done anything about them yet. I've only had the sunroof opened once since getting the car and that was only to see if it worked, which it did. There's also lots of debris in the depression around the trunk seal. There's lots of cleaning to be done after about 6 years of sitting.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

One of mine had a leaky windshield gasket

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Could a leaky w/s gasket also cause the rear foot wells to flood?

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

The water flows right out of the front foot wells and goes to the rears. They are a lower point in the car. I just fought this for 2 years on the wagon and it turned out to be the windshield seal. Sounds like your front and rear seals are leaking as a leak up front shouldn't end up in the trunk wells.....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

I've seen plenty of rear window gaskets go bad and leak. I have to replace one in my 240D right now!

Hinge pockets and sunroof drains are the most common ones I've seen.

As previously mentioned, water in the rear foot wells is usually from a leak at the windshield. The rear wells are the lowest point of the chassis interior. The side trunk wells can be the rear window, trunk lid seal, or the tail light seals.

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Don't Chrome them; polish them

The drain beside the battery is probably blocked. Clean it out and see if that stops the issue. If not, remove the battery and battery tray. There is probably a rust hole somewhere under there, either under, behind, or beside the battery. Rust perforation in this area will cause water in the passenger rear seat footwell.

The good news is that is the ONLY spot of rust on my 123. The bad news is that I am having a difficult time finding time to repair it.

I also go for the windshield, the water can just go right under the front floor mat and pool in the rear. If its been sitting for six years, I hate to think what the floor boards look like.

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For Sale: 1982 MB 300TD
1995 Chevrolet Suburban 6.5TD

Sold: 1980 IH Scout Traveler- Nissan SD33T Diesel

On my wagon, I had leaks in the windshield, hood hinge drains, under the battery tray, driver side door seals, clogged sunroof drains and bad quarter window seals.

I would say the windshield is "most likely" the cause of the water in your rear floors.

I currently have a leak-free wagon (it's not on the road right now, but it's leak-free).

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Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

Yah - I need to reseal my rear window glass - I've got ponding in the trunk too.

I've heard on here that a butyl sealant is better than silicone.....any recommendations/sources?

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1981 240d - 135k - Arlene

I got it at Home Depot or Lowe's. You need a caulk gun for it.

Silicone sealant causes rust since it traps corrosive moisture as it cures. If you use it between the gasket and the glass, it will glue them together making future removal more difficult.

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Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

My wagon had a lot of water leaking into it at first. Replacing the seals in the sun roof seems to have stopped all of it for the time being. The windshield gasket is dry and cracked, so that will probably be next. I'll have to check the hinge drains.

I saw a very small snake, just like the larger ones plumbers use on Harbor Freight Tools' website. It's small enough to use for cleaning out the drains on these cars. I think someone else may have mentioned it before, but it seemed worth repeating.

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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