Reducing Interior Noise

chope97

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I have a 73 3.0 with a ZF hp 22 with the dip stick on the driver’s side. I have owned several Bavaria and this the noisy car. One noise is the transmission, there is a hum that gets louder as you drive faster. I have changed the fluid and filter and it shifts fine. The front firewall sound deadening is missing. There is no Tran’s tunnel insulation as far as I know. The second area is the front windshield gasket is making wind noise. The third area is the rear muffler. I have a new rear muffler and I can hear it in the car coming from the back seat. Another issue is the doors, I have adjusted the doors but I still have to slam the doors to get them to close all the way and they make lots of metal on metal noise. I could use some new door frame gaskets but don't want to pay $400 for each door, is there an alternative? I don't expect my car to be as quiet as my 2004 BMW 530i but some improvement would be appreciated. I plan to redo the floor insulation in the future. Thanks
 

bavbob

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Have you pulled the back seat and the door cards to assess the integrity of the original insulation? For example, I found all my door insulation had dried and fallen to the bottom of the doors, catching debris and water and blocking the weep holes. It is a royal PIA to clean up any old and nonfunctional insulation but that is what may be needed. Start with the back seat, easiest to remove and see what you have left to work with.
 

chope97

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thanks Bob, I have done both front doors went in there to clean and lube door locks and window tracks. I did what you suggested I added a piece of insulation inside both doors. I also removed the back seat and added some duct insulation to the back panel. in fact backseat is out now as I am trying to get the rear seat cover redone, I will revisit my work.
 

billpatterson

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Hi
There are several insulating grommets that go on the door latch and locking rods / mechanisms. They usually break over time and cause a helluva rattle. Easy to replace with new ones; mainly remove door card and vapour barrier then its long fingers and a bit of red grease to help the install.

grommet

https://www.autohausaz.com/pn/BM-52208238999


1638844225651.png



Cheers
Bill
 

rsporsche

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@chope97 have you given any thought to spraying sound insulation under the rear seats / wall of the trunk - which will be covered up by the rear seat. spraying the underside of the parcel shelf inside the trunk will help as well. we are spraying the entire inside of my coupe while its apart
 

bluecoupe30!

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Sound and heat insulation are huge issues with Classic cars. None were prepared to really insulate occupants from heat and noise. Today, there are many options to deal with this. But it is a big job. Interior must be gutted to do it right. Floor must be exposed, cleaned, then an application of one of those *Mat products. Insert Dyna, Hush, X, or your choice, but this has to be applied to the floor and tunnel and as much of the bulkhead as you can reach. Then there should be some sort of matting on top, between the *Mat and the carpet. I like the DEI product, a 1/2 inch thick mat that minimizes heat transfer and sound intrusion. Like a big carpet. Cut to fit. Best modern system to solve your old car heat and noise problems. Must have everything out of the car. But a wonderful opportunity to get at all those other fixes you want to address as well. Just my opinion, doing all of this right now. :cool:
 

bavbob

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I went with Eastwood 1/4 inch X mat after removal of all old insulation (gutted interior) followed by 1/2 inch Dynamat foam, then carpet and then Coco Mat. I did run that Xmat way up the bulkhead to the level of the dash in places. The tunnel got the same treatment except where the center console is becasue the thickness would splay the console out and yield a poor fit. I call the interior my "Get Smart cone of silence" for those of you old enough to know what that means.
 

bluecoupe30!

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I went with Eastwood 1/4 inch X mat after removal of all old insulation (gutted interior) followed by 1/2 inch Dynamat foam, then carpet and then Coco Mat. I did run that Xmat way up the bulkhead to the level of the dash in places. The tunnel got the same treatment except where the center console is becasue the thickness would splay the console out and yield a poor fit. I call the interior my "Get Smart cone of silence" for those of you old enough to know what that means.
Hmmm, makes me think of an episode with "The Craw", and endless, "missed it by that much", or "Would you believe?" pleas. Funny show.
 

eriknetherlands

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Noise Isolation is difficult as it has numerous points of origin: exhaust, tyre noise from the classic threads, noise from debris slung into the body (modern upper class vehicles often have plastic damping inside the wheel wells), wind noise from door and window edges is almost not fixable; the only thing about this is make sure you have all rubbers in place, and adjust your doors so they stick out at the trailing edge to the rear fender by a hair, even +0,5 mm will work, as long as the door is not 'underflush' as it called.
One of the best way to see if it's ok is to check after a long drive: if the door has a bit of 'overflush', then dirt will collect on the panel just behind the door as it gets sucked into there.

Regarding heat insulation I consider it best to tackle it at a point closest to its origin; the exhaust and heater core. minimizing the input there requires less material (= cost and mass) compared to trying to cover an entire floor with heat isolation material.
Don't know about e3, but at least e9's have a foam + heavy rubber mat on the transmission tunnel.
 
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Ohmess

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In general, any wide expanse of sheet metal will transmit noise. Door panels, roof, trunk lid, etc. Alas, glass also allows the transmission of noise, and older cars have a lot more glass than more modern cars.

Since you have done the doors, the next area to address would be the floor the car, to include the tranny tunnel. A set of cocomats over the existing carpeting would help too, and they look good.

And since you have your rear seats out, make sure to insulate the area where the wheel wells intrude into the interior. This is a likely source of low frequency noise. Then extend this insulation to all of the flatter area behind the seat backs. The parcel shelf too should be insulated. Doing the wheel wells and floor inside the trunk will help too. Here again, the most important area is the inside walls of the wheel wells.

Also, as to the transmission, check the foam insulation around the shift lever underneath the console.
 

Frederick

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Noise Isolation is difficult as it has numerous points of origin: exhaust, tyre noise from the classic threads, noise from debris slung into the body (modern upper class vehicles often have plastic damping inside the wheel wells), wind noise from door and window edges is almost not fixable; the only thing about this is make sure you have all rubbers in place, and adjust your doors so they stick out at the trailing edge to the rear fender by a hair, even +0,5 mm will work, as long as the door is not 'underflush' as it called.
One of the best way to

Regarding heat insulation I consider it best to tackle it at a point closest to its origin; the exhaust and heater core. minimizing the input there requires less material (= cost and mass) compared to trying to cover an entire floor with heat isolation material.
Don't know about e3, but at least e9's have a foam + heavy rubber mat on the transmission tunnel.

Hmmm, makes me think of an episode with "The Craw", and endless, "missed it by that much", or "Would you believe?" pleas. Funny show.
"Not Craw, Craw!!!"
 

Rek

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The seals between the engine and the internal firewall where the fan motor sits can affect noise a lot. I found the factory products didn't seal well and I played around with profiles which did seal. Any gaps will let the engine and header noises in the car.

As for wind noise, the wipers, the window seals and the side windows generate a lot of noise. The worse culprit was the gulley with the chrome trim which runs the length of the windows over the top. I used expanded neoprene tubing with a closed cell and fitted this within the gulley which prevented a significant amount of noise from the front and now keeps out water.
 

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Rek

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Those keen eyed elves amongst you might notice my paint now has goosebumps. This developed over a spell of cold weather after over 8 years since the car was painted. It was outside under a waterproof car cover. Any ideas on what might have caused this? If it was water under the paint I would have thought that it would have shown up well before now.
 

eriknetherlands

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Goosebumps usually is moisture trapped inside the filler layer, typically during the painting stage. My car has them as well. They get progressively worse over time.

Interesting neoprene solution. Looks very stealthy, oem almost. What if it gets wet, doesn't it get wet under the neoprene, and then stay wet for days?
 

Rek

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I tried it fitting first then used a hosep[ipe on it. Once I took the neprene off it was perfectly dry. As it is closed cell, the neoprene kept the water out.

As for the goosebumps - its taken quite a while to come through and then appeared almost overnight. It is due some bodywork and a repaint soon though.

For now, it will have the 'painted in porridge' look.
 
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