Hey guys I need some help here... My 02 sensor is on so tight I can't get it off. I jacked it up, got underneath it, and used all my bodyweight and couldn't get it to budge at all. It's seriously like it is welded on it is so tight.

Any suggestions to get it off before I take it to a mechanic to take it off...?

I recently tried changing the ones on my wife's Blazer. Got two changed but the other two had to be cut out and rethreaded by our local exhaust shop. I was using the proper O2 sockets by the way.

Sometimes they'll come off easier if you do it while the exhaust is hot. Be careful if you try this and wear protective gloves - I have the scars to prove what happens if you don't!

Also helps SOMETIMES to PB Blaster them for a week before trying. Then do what Rambler said right after spraying them. Didn't work in my case though.

Heat is right. CRC has a product called "Freeze Off" which is a penetrating oil with a super cooling agent. Kinda like turning those "duster" cans upside-down. Can help a lot in breaking a rust-weld.

In my case an oxy-acetelene torch heated it until it was red...

Cut wire to fit 7/8 box wrench. Sometimes seized will free it you can deliver a crisp solid whack to the wrench while torque is applied.

No harm ether in seeing if it cracks free going the other way.

I used a propane torch on mine until they started turning red. Then the O2 sensor socket wanted to flare out so I clamped it together with a set of vice grips and put a breaker bar on it and it popped and broke free. Had to do this to both of my O2 sensors today to get them off.

Thanks guys the torch trick worked like a charm!