Does MB in 81 have them? My 81 300SD has like two square looking things that are located way in the back of the exshaust system one large pipe from the front all the way to the back to them does this indicate that those are the cats?

They're not catalytic converters, they're center mufflers.

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

No, The first year with anything like a Cat ( actually a Trap Oxidizer) was the 85 californian emissions model.

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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

http://ecomodder.com/forum/fe-graphs/sig692a.png

They might be the pre-muffler silencers. I've never been under an 81 though. That would be a 116 chassis, right?

My 82 has just the rear muffler, no centers. It is nice and throaty sounding! ARRRGGGGHH!

Goto www.*************** and look up parts for your car. See if they show a part that looks like yours. Then you'll know what it is (and what it costs! )

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-Matt

EPA Section 609 Certified MVAC Technician
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Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

I always called it a 'Resonator' but I looked @ the TSM and its actually called a 'Resonance Damper'

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Cheers,
Robert

Thank goodness they do not have them. They are called resonators and the muffler is in the rear.

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair