My mechanic says the 1500rpm resonance I hear is coming from a loose baffle in the passenger side muffler of my 05 500SL. He recommended that I send it to a local converter company to see if they can open the muffler and spot weld the baffle inside. I have an appointment in a few days for them to take a look.

Does anybody have experience with doing something like this? Any idea what this might cost?

 

Not sure if I understand where the "muffler" is you mention but if it is the second cat converter (middle of system) I just took mine out and went straight pipe. Works fine very little noise difference. If it is the main cat converter up by the engine it sounds like a problem. The O2 sensors are in it. No problem with check engine light taking off the smaller converter. Other members report the same result as I found. If you are talking about the small muffler at the very back of the bumper I'd replace it.

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