Why does it sound like my rear driver door is open????
 

While driving my 1985 300TD, when any car goes past the driver side of the car, it sounds like the rear driver door or window is open. I went for a ride as a passenger to see if it sounded the same on that side, but the sound is much more insulated on the passenger side rear door.

I've checked the door seal, wind lace, window seals, and made sure the door is closing properly, and I can't find anything that looks like the cause. There are no leaks in or around the door and the plastic liner is in place.

Any ideas as to why I'm getting so much noise through the back door?

Not sure where you are located, that is with respect to rust, but I would lift the floor mat and check that the drain plug is still in place. When the floor starts to get soft, in my experience they sometimes rust first around the lip and fall out--so things get a bit noisier.

I sincerely hope it's something more palatable, btw.... :o

chad is the rust repair master, so if it's rust, he'll find and fix it!

are you sure your window is all the way up? are there any cracks in the window track seams?
have you pulled the door panels, and looked to see if there are any holes in the molding trim plugs missing? is the vapor barrier intact? have you put dynamat on there?

You had me worried there for a minute.:D

I repaired the rear driver side floor when I first got the car and just went out to see if my work was failing.

Luckily, it still looks as good as the day I finished it and everything is solid. I also have the original carpets with the molded foam back side and heavy duty Coco mats in there, so I don't think I'm hearing the noise through the floor.

Ha! Thanks John.

The window regulator is a bit worn out. Sometimes the window drops about 1/8" to 1/4" and when I put it back up the regulator clunks. I thought it was due to that at first, but even when I'm certain the window is completely up I still hear the noise.

I recently replaced all the window brushes and replaced the vapor barriers with heavy duty plastic sheeting. All the molding and trim plugs are intact.

I haven't put any Dynamat inside the door, but I have some left over from the last TD I worked on, so I guess I'll try that.

Rear sunroof seal.

Mine is not making good contact right now on the passenger side and I keep thinking the RR windows is cracked open...

I replaced the sunroof seals about 2 years ago and just went out to check on them.

They are still looking good and making contact where they should. The brushes are still good too.

Thanks for all the suggestions so far guys.

After the rust shocker - that I thought of too - I've thought of a really simple one to fix!




Is the window fully wound up?

Rear door weather strip seals are getting old and not sealing well. They may be present and appear good, but they can still let air noise through.

The door seals are less than 3 years old. I replaced them myself. I even verified the seal was making contact everywhere by putting some grease on the seal and making sure it made a stamp on the complete door frame.

After checking over everything again, I think it might be the window seal around the fixed window in the rear door. It has more play in it than the passenger side fixed window. If it's the source, I'll either look for a new seal or squeeze some butyl sealant in behind it.

I'll have my wife take me for a ride when she gets home. I'll sit in the rear driver side seat and take notes.:D

When you go for your ride try pressing lightly on the window & see if the noise goes or changes.

Another trick is to use masking tape. Tape around the door seals and window seals or any other place there may be noise coming from. See if the noise goes away. Then start removing the masking tape, (one area at a time) drive around, listen for noise, when noise returns you've found your problem spot. (Masking tape is cheap)

I can't believe I didn't mention the back side window... I typed it out... I've pulled them several times. lemme know if you want the seals from my parts wagon. (or entire windows) I'm pulling the front end for byronashh and most of the regulators are total junk...

I have a regulator rebuild kit sitting in my garage, I just need to pull it out and fix it.

I'm interested in the seals. You wouldn't happen to have the "D" pillar trims in good condition would you? I don't care what color it is since I have SEM Color Coat.:D My trims are warped and cracked and kind of hanging there, but I can't bring myself to remove them completely.

Heh, I'll check, exactly what is the Dpiller trim? the front or middle ?
when I say the regulators are junk, I mean, they have been WELDED TOGETHER with some kind of aluminum solder, and wire tied in the open position...
odd that no water to speak of gets in the car, MB really designed the rails of the car well.
I pulled one of the rear windows to inspect the rubber, they are pristine. powder still on them.