I own two 126 300SDs (1981-272K miles and 1982-291K miles). The 1981 was developed an exhaust noise which sounds somewhat like a Jacobson Exhaust Brake. It resonates between 1000 and 1400 RPM. I have completely removed the entire exhaust system and inspected it for any holes or dents in the resonator or rear muffler. I have replaced the exhaust seal as well as all of the hangers. There is nothing physically hitting. I even got a used system from Pull-a-Part which didn't change things much. The noise appears to be coming from the area of the left branch of the center resonator/silencer.

The motor mounts are new Lemfoerder mounts and nothing is hitting in their area.

My 1982 is also starting to exhibit some of this noise, but to a much lesser degree.

Has anyone out there had to replace the center resonator/silencer due to noise?

Any other thoughts as to the source of this noise?

Thanks

 

if you can put your car on a left it will help find your problem put somebody in it and have them bring the rpms up to the range which you hear the noise then inspect for it. pre 98 mercedes benz exust systems were pretty bullet proof but all bets are off with the mileage you have on your yours.

of coarse anything is possible.