So my 2010 Prius recently got a code for the upstream O2 sensors heater circuit (P0031) and I tested the heating coil and the circuit is not complete so I ordered a new one. The old one obviously is pretty well stuck on there so I have been researching the best ways to get it off. One interesting way was using dot 3 brake inplace of penetrating oil. Has anyone used dot 3 brake fluid to get an O2 sensors off? Is it safe to use since it’s flamable? I have a lot of dot 3 sitting around so it would be great if I could use it. Thanks in advance and sorry if I missed this mentioned somewhere else. I saw it mentioned for removing normal screws and saying it was falamable, hence why I was curious if it was a good idea on an O2 sensor.
So the new O2 sensor is placed in the vehicle...but I did not really get a good use of the solution I made up. There was this flange attached to the stock O2 that I shot the fluid into but the fluid barely made it on the other side of the flange and on the threads (see attached image). With out taking it off I thought this part was just part of the exhaust manifold shielding but I realized I was wrong once I took the O2 sensor out. Not enough fluid got on the threads to tell if it really works or not. I had the run the engine for about 1 minute to warm it up just enough to remove the sensor and with a cheater bar it came off. I can confirm it is safe to use on the exhaust and for O2 sensors (probably not good for a new one though) because my car has not caught on fire or had any harm done to it. Thanks for all the comments guys! And hopefully someone else can also confirm this solution mix of 50/50 dot 3 and acetone really works!!