Doug2.7

So I bought a "new" Bosch O2 sensor off ebay and when I got it, the sensor had anti-seize on it and it was sooty and a bit discolored. I wrote the seller (lots of +++) and he states that Bosch puts anti-seize on them... I left for Christmas and have not had time to check again with him. He did state there were no wrench marks on the collar and that is true...

So, do I have a new O2 sensor or used one? Can post photos once I get back home...

indoor

Anti seize grease is normal on new sensors, and it is covered by a plastic cap..I don't know about the color of the metal sleeve that covers the actual O2 sensor, I think that's stainless steel and should look like it... I would look at the wires too. But he has a good point about the collar marks(you have to torque them down a bit so as not to leak and that would leave some marks).