Ok how can i get this O2 sensor out ive tried everything including heat. 4.0 HO

 

PB blast or kroil or something. Let it soak. Might also get the o2 sensor socket.

 

or a big open end wrench the right size

 

I often have to heatem up red/orange with the oxy torch, heat only, don't hit the oxy cutting lever, some take up to 3 applications. I have a ceramic antiseize that I apply on these and any other fastener in the manifold or exhaust system application, ensures I can remove with ease in the future. (for example SBChev in 1/4 mile oval application, manifolds are red hot every race, no problems with manifold bolts using the ceramic antiseize). It will take some heat to get the O2 sensor to co-operate.

 

I chopped the wires so a 7/8 box wrench would fit. (freddgr's tip). Allot of torque with a crisp smack sometimes helps with something seized. Ideally the manifold would be hot, and the sensor cold. (I don't think torching the sensor in a cold manifold would help much). Metal expands hot of course.