Rounded Oxygen sensor
 

I have a 85 380sl.. I am trying to replace the oxygen sensor. I rounded the sensor. I tried just about everything to take it out.
One stupid question is , Is the sensor normal threaded or reverse threaded?
thanks

normal thread, you are going to have to heat it up really good and use big vice grips to twist it out

good luck

Can you get a pipe wrench on it? Unstoppable! (unless something else breaks first...)

I thought I had a patent on this. :D

Get a chisel and a hammer
 

use a chisel and hammer. Keep tapping on it (as close to the thread as possible) till it turns a little then use a 12 point wrench and turn it. If you can heat it before you hit it, that would be even better.
Good luck

I took mine off the 300E cold, but on the BMW, I let the car run for about 15 minutes first. Makes it much easier to remove. You might wear heavy gloves to help avoid burning your hands.

Finally did it.. I used a propane torch to heat the sensor for a good 3-4 min.. then put water on it.. then use a pair of vise grip and start hammer it.. it came off. then i used a runner to clean out
the threat.. The new sensor screwed in smoothly...now the rough idle is gone..