Ok, I've got an '87 240 Wagon with the stock exhaust (no Turbo or mods). My 3-wire Oxygen Sensor is firmly bonded/rusted? to the manifold and I can't unscrew it.

I acquired the Oxygen Sensor Removal Kit (free rental from Autozone and it's the same parts that IPD sells for $20), but even with the special wrench, I'm rounding off the 6-sided Bosch sensor. The sensor is old, and it's been in there for many, many years.

My 2 failed attempts were with the engine cold and no penetrant, using the special O2 sensor removal tools. (I thought I could do it without penetrant and it seemed to work until I realized that I was rounding off the bolt) I first tried the reinforced 3" long silver 22mm socket with the wire-cutout, followed by the short black open-back/offset socket (which is pictured in the IPD catalog).

What should I do from here? I'm guessing I have the following options:

1. Run the engine and get the exhaust as hot as possible. Assist it further by running a Propane or MAP Torch on the exhaust manifold to heat it to a horrendus temperature. -Then use the O2 offset socket and attempt removal. (this was actually suggested by my local Volvo dealer service department but I'm not sure the service tech I talked to has done this before)

2. PB-Blaster while manifold is cold (or slightly warm?). Use the O2 offset socket and put a hose clamp over it to prevent it from expanding and attempt removal.

3. Some other option that you (the reader) has discovered when you encountered this problem.

I'd like to succeed on the next attempt, since more failures will only make it harder on the next try. I'd like to take the car on a road trip to Dayton, Ohio, this Thursday-Sunday so time is of the essence.

Thanks for your help and suggestions, God bless,
Fitz Fitzgerald.

P.S. The old O2 sensor is still functional, but it's slowly dying and under normal/correct exhaust it shows a "false" lean condition. Thus, the car is running rich to compensate and I'm loosing several MPG.
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'87 Blue 245, NA 214K