stuck sensor

[Mountainman]

i bought an o2 sensor and was gonna take the old one out and the thing is horribly stuck in the exhaust(100,000 since last change). i sprayed everthing i could find in our shop on it and wrenched it to the point of almost breaking the thing off. any ideas how i should best approach getting this off?

[mkgearhead]

I use GM 'heat valve lube' works good. Sometimes you have to tighten/loosen back and forth to get it out without galling the threads out.

You might have to heat the bung around the sensor with a torch too.