I have recently had the oil drain plugs in both my cars strip. I have always been careful of the 40nm torque. Is the plug softer than the female threads in the pan? On the 240D, I was able to remove the stripped plug and put a new one in. Yesterday on the 300D. I could feel it strip at about 30nm. I could not get it to back out. Even with prying and turning.
I had an old pan, new plug, and new gasket. I swapped it out. I was careful about the 10nm on those small bolts. Do real mechanics use a little blue loctite on them? I now have a small drip on the right side of the pan. I will double check my torque. I think the gasket goes in dry, right?
I think this is the universe telling me to start suctioning out oil.