Bank 2 lambda removal

[Braz86]

A bit of help required.

I have replaced 3 of the 4 Sensors, and the only one that I can't get out is the one throwing up the fault code

It's in such a tight gap you can't really get anything decent on it, and the 22mm spanner is slipping on it, and I'm worried 8 may round it too much

I have sprayed it with oodles of penetrant, heated it up, tried a number of sized spanners, and still nothing. I'm out of ideas!

Any help and suggestions very welcome. Here's what I'm up against

 

[t-tony]

You usually find with CO sensors one of 2 things happen. 1) they crack off and unscrew with your fingers, or, 2) they start to unscrew then tighten up as the thread strips. In the 2nd option you will end up with one or two options, try and make it screw out (sometimes the thread strips) or remove the exhaust and work on it in a vice on the bench.
I have found that the exhaust needs to be bloody hot or stone cold before attempting to remove the sensors. Cold is best.

Tony.