97 BMW Z-3 4-cylinder catalytic converter

!) Could an “on-and-off” metallic sounding rattle underneath the car mean the catalytic converter is going “bad?”
2) Could an after market replacement work as well as the factory made part?
3) If so…any recommended manufacturers or suppliers?
4) Would it be totally stupid to consider a salvaged CC?
5) Any suggestions would be appreciated!

  1. It’s more likely one of the heat shields on the exhaust system, than the cat.
  2. Walker makes quality exhaust parts.
  3. I think it is illegal to buy a salvage yard cat.
  4. Check all the heat shields on the exhaust before condemning the cat.

Hey thanks!! All very good advice!! Thanks PvtPublic!

The heat shield on cat converters are stamped pieces of metal typically welded at the corners to the converter. These welds can rust, break, and the heat shield rattle. If it is this ratttling, a good permanent fix is to secure it with lage worm-drive hose clamps from the hardware store.

But you’ll need to get under the car to find out of this is the cause. Do this when it’s cold. Touch that converter when it’s hot and you’ll leave cooked flesh on it.

Hey, that’s a great idea. Honestly, my job has kept me so busy I haven’t had time to get under the car to actually check it out (I know, a pretty lame excuse). I will commit to checking it out and will let both you and PvtPublic know what I discover.
Thanks for the suggestion.

Hi Everybody who responded to my question. The large worm-drive clamp worked. The scariest part for me was backing my rear wheels up on the metal risers so I could get under the car, but it worked…got 'er done, and it soundes great.
Thank you everybody for your input. I gonna use this car repair resource again.