Due to the humidity here, rusty exhaust components are a fact of life. If the PB Blaster doesn't work, I use heat and sometimes plenty of it, to remove an O2 sensor. A neighbor brought over his daughters Japanese car to replace the O2 sensor, and it wouldn't budge. I heated up the bung until the pipe was glowing red before the sensor could be removed.

 

Nice shop to do it for free......

 

Apply gas torch heat, remove heat, jam a wax crayon to melt over the threaded bung, bingo. The melted wax will migrate into the threaded connection, greatly reducing the tendency for the threads to gall.

Saw it on You Tube, so it must work, right?



I'd give it a go, myself, if I had to.

 

Secret is to put penetrating fluid like Kroil the night before. When you try to take it off, work it back and forth which breaks off the rust holding it into the threads. Takes patience. Never had an issue taking one off using this method. I almost always cut the wires off and use a deep impact socket.

 

I agree, a soak really helps. I actually have a socket with a special grove for the wires to get past. Worked great on previous truck, have not needed it yet for current one.

 

I have that socket too but it will slightly flex if the sensor is really stuck so sometimes you just have to clip the wires and use a regular impact socket.