How do you remove a rusted bolt from an o2 sensor?

If there are specific hazards or issues with an O2 sensor then adjust these instructions accordingly.

There are four simple steps to try initially:

1) Clean up the seized fastener... use a combination of degreasers, detergents, abrasives. DON'T use wire brushes in this instance, stick with plastic. This sets things up for the next step...

2) Search for the term "penetrating lubricant". These are specially formulated to squeeze into the small spaces in fastener threads. Use the lubricant liberally. Use plastic brushes to work it in, further cleansing the area.

3) Try to rock the fastener in both directions... particularly effective if it starts to come undone then jams. Add more lube as you go... it should rock a little further each time until it frees up. if not...

4) If seized absolutely solid try a freeze and release spray... very effective and much safer than heat around delicate electrics. Check the product to ensure it is safe around electrics as this is a special situation.