Hi guys,

I really enjoy my 1983 240D with 4-speed manual.

I have need to drive it on the freeway for a few hours each week, and I've got to say, it's pretty loud at speed (e.g. 65 MPH).

Of course, newer cars have significantly better quietness in the cabin. Is it possible to have the best of both worlds (simple, rugged vehicle + quiet cabin)?

1) Has anyone successfully made these a lot quieter with aftermarket add-ons? (e.g. stick-on sound insulation in the floors, doors, etc.)

2) If so, what is the best bang for the buck and effort? What are your recommendations?

In my view, if I could take the sound level down a few dB, it would really complete the package.

Sincerely,

Packman

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83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!

I suppose a more insulating Hood Pad and some sound deadining Material on the Fire Wall Under the Hood and the same inside would help. I not sure if the same could be done on the in the Transmission tunnel.

I am not sure if there is stuff made specific for that for Cars but they have sort of an Egg Crate type Foam for deadning sound in rooms where People Record stuff.

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84 300D, 82 Volvo 244Gl Diesel

A switch to a turbo with its 3.07 gearing will be somewhat quieter. An '85 with its 2.88 gears will be quieter yet. I think you'll find that the car is already well insulated. These cars were also products of the 55 MPH era, so they were never geared for 65 and higher.

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'83 300D, 126K miles.

Dynamat is a good product and comes in sheets that stick on. May be worth looking into for what you want. It is usually used by audiophiles to help with better sound.

Making your Mercedes Diesel Quieter - Dieselbenz.info Wiki

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83 300TD, 260,000 miles, aka "Dusty"
6 vehicles, 2 cup holders (both in the dump truck)

Switch it for a 280 E

I have a recording studio. It's another (expensive) hobby of mine. Foam really only diffuses sound waves making them bounce off in different directions and they really only work on high frequencies since they have short wavelengths. It does absorb some sound, but not a whole lot. Bass frequencies have looooong wavelengths and can go through walls and what not. Most of what we are hearing in the cabs are the low to low mids unless you have a leak somewhere. Now in the pro audio world there is some stuff called Sheetblok made by auralex. It's a thin vinyl material that is about 6db more effective at stopping sound then lead. Studios use it in construction and lay it under floors and what not. It's a little expensive and I'm not sure about it being used around heat, but I guess you could line the cab with it and it will help. Maybe put it under the carpets and stuff to cut out some road noise. I'd make sure all the weather stripping is good first. if air can get in, sound can get in. The best way to sound proof something is have an insulated wall, an airspace, and then an insulated wall, but that doesn't translate well to vehicles. Hope this helps!

Buy a Prius.....

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Ack! I don't think so...

Packman

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83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!

Learn to like the noise, it scares people away

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Hi guys,

Thanks for the suggestions. I'm leaning towards this stuff Tomb like silence & luxury car quiet with Spectrum and using a cheap spray gun to apply it.

My thinking is that the majority of the noise is likely due to the vibration of the structure of the W123, and the various exhaust, road and engine/tranny noises being transmitted through the car's metal structure.

The problem we have (at least I assume) is that there is quite a lot of material already in the car, designed to help dampen the vibrations. You see the material whenever you pull up the carpeting, or pull off the door panels.

It's everywhere.

For the door panels, I'm thinking that cleaning the interior of the doors with solvent (e.g. paint thinner). I note that the panels I have pulled already have some kind of sound dampener stuck to the sheet metal. Therefore, whatever I do would have to stick to the exposed sheet metal AND the top of the existing sound dampener. I think that the spray-on Spectrum product seems like it would work well.

For the floors, I am considering pulling up the carpet and applying something to the top of the existing factory sound material. I've pulled up the factory sound material before (well, it has to be cut and then scraped out!) and there's no way you can effectively pull all of it out. I think that something like the Luxury Liner product Luxury car quiet with our noise insulation products Luxury Liner would work OK. I don't think that spraying the Spectrum product on top of the factory sound material would help much, and would likely make a big mess.

I suppose that using a pressure washer on the underside of the car, along with something like a strong degreaser would work to clean the bottom of the car. After it dries, if I simply sprayed the Spectrum material over the top of the existing undercoating it may have some good effect.

Thoughts?

Packman

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83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!

Add more speakers on radio.

Turn up the radio and put in ear plugs. Amazing.

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83 300TD, 260,000 miles, aka "Dusty"
6 vehicles, 2 cup holders (both in the dump truck)

Earplugs.

Seriously, they are a lot lighter, easier, and cheaper than other solutions. I use them when I take my motorcycle for long rides. When I had to drive my 240D 500 miles with a cracked exhaust manifold, I used earplugs as well.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Yeah I use ear plugs also, just a habit from running equipment and driving dump trucks. but long hours of driving and the drone of the engine, wind and road noise get to me after a while.

I installed a 3:58 Differential and that drops the engine speed about 3%.

I removed the rotted old hood pad from the 240 and drove it around for a year or so. then finally bought a new pad. It did make some difference though, now Iam use to it doesn`t seem to have done anything. everything does help.

I have been thinking of taking out the rear seats, remove the MB paded plastic covered stuff, (not too sure it does anything and adding Dynamat to the back panel and floor under the seat. might be good to remove the rear shelf and cover the metal under it too.

The tar pad insulation MB put in 30yrs ago doesn`t really do much now that it has dried out and usually is cracked. I would remove it and clean the floor good before applying anything to make sure it will stick. plus if there is any water leaking in, you do not want it traped under the insulating material and causing a rust issue.

If you really want to get into it and have a good sound profed 240, remove the dash, heater/AC unit and do the firewall on the inside. the heat/AC unit probably need to be cleaned and overhauled anyway.

I read about Lizard Skin a product that is sprayed on.
LizardSkin® Spray-On Insulation | Lizardskin

Did a Google search on it, then read some other forums of mixing some beaded stuff in regular paint and the results are the same as the Lizard Skin, and much cheaper.

Alternative to Lizard Skin - ChevyTalk --The Social Network for Chevy Fans

Alternatives to Dynamat and Lizard Skin - MonteCarloSS.com Message Board

http://www.crankshaftcoalition.com/wiki/Ceramic_insulation

some NASA related ceramics
All About Ceramic Insulation

Keep searching and more stuff comes uo.

Last resort, you could wear some of these. color is up to you.

ear muffs - Google Search



Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works