O2 Sensor Stuck

[ClaytonFLong]

I tried to remove the after cat converter O2 sensor and managed to get the torque broken but then it seized up After about 3 turns. I’ve tried running the engine to heat it up but there it is still in the same position. I also can’t tighten it back down fully.
Anyone have suggestions, been in this situation?

 

[OR VietVet]

Use a penetrating fluid on it. The best I have ever found is called Aerokroil. Let it sit for a while and spray a few times over that period. I would tighten the sensor down again and spray then and then when you do try to remove again you can also spray a little in there after each full turn. The threads could be damaged when you get it out so try to clean them up with a wire brush and lube the threads when installing the new sensor. Turn the new sensor in a little at a time until you can feel it moving freely.

 

[Doubeleive]

torch

 

[OR VietVet]

Ahhhh, yes, the hot wrench approach.

 

[Rocket Man]

PB Blaster a few good soakings over several hours, then a torch and if that doesn’t work drill it out and chase the threads. Worst case scenario you have to weld it up and add a new bung but that shouldn’t happen.

 

[wjburken]

Sounds to me like you may have galled your threads by trying to force the torque without any penetrating oil. If that is the case, no amount of penetrating oil will help now as you likely have metal burrs locking with metal bites. If heating it with a torch doesn’t help by “softening” the metal, you may need to drill out the sensor and clean up the threads with a tap.

 

[George B]

I think the only way your going to get that out is with a torch. Get the fitting orange hot and thread the sensor back in first. Add more heat and back it out. There is a good chance the fitting will be damaged. I would chase the threads with a thread chaser tool before installing the new one. Don’t over tighten the new one as there may not be much thread left.