I have a 2008 Mini Cooper base automatic and the upper oxigen sensor is faulty. I need to change it. Have someone done this before, is it dificult to do it, do I need a special tool?

 

Pretty simple; remove the electrical connection on the oxygen sensor.
Then take an oxygen sensor socket / ratchet or adjustable crescent wrench, loosen it and remove from the exhaust.
Install it by reversing directions; DO NOT use any anti-seize or thread compound.

- Erik

 

YES you should use Anti-seize on the threads, just a little so you can get it out later if you need to take the exhaust off. Most 02 sensors actually come with a little anti-seize already on the threads and have a plastic protector over them. The important thing is to not get it on the tip.

 

A crescent (adjustable) wrench? No no no no no! The adjustable wrenches are not secure, their jaws will open up and they'll just round the bolt head. At least, on any bolt that is corroded or stuck at all.

There's a reason that the O2 sensor sockets go almost all the way around the sensor. That is much more secure, and allows you to put more torque into the bolt head.

Crescent wrenches are OK for home repair projects, but you shouldn't be using them on a car IMHO.