Where are the drains that I need to check? Water still coming in drivers side front floorboard - it's been raining too hard to check passenger side. Windshield seal is brand new, MB-OEM, and looks like it's solid. I included a picture of firewall/eng compartment... I see two holes mid-firewall that look like drains, and were trickling water into the eng compartment...

Edit: Just had windshield seals (frnt/rear) replaced, is there anywhere I can get into to check if it is actually the seal? Although I am hoping it's not the seals, it wouldn't surprise me if this shop didn't get it right... I can't figure out where the water would come from if it was the windshield seal, and the drains seem like the next place to check...

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1969 220D - 4spd std
1973 220D - 4spd std

Check for rust holes in the fire wall, down near the top of where the tranny is bolted to the motor, its common for the early 114/5's to rust there.

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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

The joint formed by the drainage gutter (below the cabin air intake) and the firewall is very vulnerable on this chassis. The leak may not be located exactly where the water enters the cabin because the rubbery sealant fails, but not completely. Where it admits water into the cabin is not necessarily where the metal joint has failed. These kind of leaks are very hard to nail down. I wasn't able to find and fix all of mine until I took the dash and console out completely. I wouldn't have done that, but I had to replace the heater core and blower.

Best to start by removing the carpets and the under-dash panels to expose the inside. Then you can at least see water running down the firewall, and possibly where it originates. Cleaning out the drain gutter may also yield some information. It's actually possible for the gutter to be loaded with enough junk that the drains clog, and water backs up and enters the the interior through the cabin air intake. You don't need much more than an inch of water in there for that to happen.

If the front windshield seal is bad, the most likely place for it to leak is at the corners, and the water will drip down behind the side panels in the footwell. Same for the rear, but in that case there will be evidence of leakage in the back part of the floor, the parcel shelf, and in the trunk.

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'79 240D

Gahhhh! Found a dripping rusted seam in firewall corner under the dash. I can't see the other side from the engine compartment, brake booster is in the way.

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1969 220D - 4spd std
1973 220D - 4spd std

Pull the wipers and the intake grill, and dig into it from above. Nothing to see behind the brake booster that won't look worse from the inside. Probably not that hard to fix as long as it isn't in the hinge pocket.

Forgot to mention that there might be a rubber plug on the bottom of the gutter, up behind the driver's side hinge pocket. It is located at a high point in the drainage. If it is there, it could be a leaking. This was the source of an annoying drip running off of my parking brake control, but it also contributed to water running down the interior side of the firewall.

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'79 240D

@ Left Coast

Thanks for the insight - this is driving me nuts.

Sorry, stupid question incoming. Can't go out and look at the car right now because of torrential downpour. The hinge pockets are the cavities underneath the hood hinges, correct? I cleaned them today with compressed air, I didn't see a rubber plug. Is it visible from the outside, or is it a stifff neck view from inside the car?

I used compressed air to blast hinge pocket drains, and the 3 drain holes that are just above where the trans mounts to the motor, which presumably drain the grill below the wipers. These are the only drains that I could locate. A mechanic I talked to today said that the wipers looked sealed, he didn't think they were leaking into the firewall.

I see where water goes into the hinge pockets; where does it drain out?

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1969 220D - 4spd std
1973 220D - 4spd std

Correct

It is not visible from the outside. If you pull the wiper arms and the air intake grill, then you can reach in and feel it, approximately behind the hinge pockets. It is a small plug, no larger than 10mm. You could probably reach in and feel it from the inside as well. If it is there, it should be located in the area in front of the drivers side dash vent. I don't know if you can see it with all of the under-dash stuff in the way. I didn't see it until I removed everything inside, but I had no idea that it was there until I discovered it.

Blowing the flap drains below the air intake (you do still have the rubber flaps over those holes, don't you?) will just push crud away from the drain hole, and possibly in to the heater box. What isn't blown into the heater box will soon return to the bottom of the gutter. The better way to clean this area is from above, with a shop vac. In any case, water failing to drain at that point will not cause it to enter the cabin unless the seal between the drainage gutter and the firewall has already failed. If those drains are closed off, then the gutter should hold water until it rises high enough to enter the heater box through the blower opening.

If, in fact your problem is a leaky seam, and if you want a permanent solution, then you'll have to work from the inside of that gutter to seal it up.

I don't know how one can tell that the "wipers look sealed". That said, the wipers are seldom the cause of water leaks.

The drain paths for the hinge pockets themselves are under the hood. The drivers side hinge pocket drains forward, then down around the outboard side of the wiper motor and transmission, finally down through a drain hole in the frame rail. The other side is similar, but somewhat different.

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'79 240D