The o2 sensor is stuck on the back header of the engine. I need to replace it because my cel is on. If I try and put gorilla torque on it will the threads be damaged on the exhaust manifold? How would I repair this without removing the exhaust? Can I just thread the o2 sensor on the few remaining threads and put some tack welds on it?

 

Can someone also tell me what size tap I might need to clean up the threads on the o2 bung? Thanks.

 

If your going to replace the sensor, buy it then measure the thread diameter.

Typical sizes are 18 mm x 1.5 or 12 mm x 1.25. You should be able to tell approx diameter by looking.

Thread damage is a common, thread chasers exist for this problem. If the threads are to damaged the bung can be replaced.

Use an oxyacetylene torch to heat the area plus an 02 sensor socket.

 

1. lots and lots of liquid wrench. soak it and let it sit and soak again
2. you do use O2 socket, don't you?
3. sometimes you can get lucky and get vice grip on the nut part of O2 sensor. gives you much more torque.
4. lord save you from breaking exhaust.
5. you can try tapping on O2 sensor seat in the pipe, if you can. impact wrench would have been ideal, but I am yet to see car that can use it there