I have a 2001 Mitsubishi Lancer 1.8L sedan. It has one O2 sensor and I am having a nightmare taking it out. Tried with O2 sensor socket, 22mm wrench , kept on applying penetrating oil (Boston aerosol oil) and revving up the engine...Almost about to give up. Any tips please?
Well I assume you're going to put a new one in and throw the old one away so you don't care if you ruin it
. In that case you heat the sensor and the pipe it screws into it with a torch until it glows red hot then it will come out. And of course the best thing is to have a socket that fits it perfectly then have a three or four foot long extension bar to use to get better leverage to snap it loose
I went through 8 O2 sensors on my 2 cars within 20+ years. Some of them were a true pain to remove.
This is what Ive done when nothing else inclusive gas heating worked:
I jacked the car up high, and placed a reliable socket on the O2 sensor. Important is to make sure the socket is hexagonal, and not a, say, 12point star socket or a ring spanner. Ordinary open-ended C-formed wrenches cannot be used either. Also make sure the socket geometrically fits your O2 sensor as tight as possible (sockets have some play, and it may vary from socket to socket. You want the smallest play you can get). To the socket, I attached a reliable socket wrench.
Then, I attached an extender to this socket wrench. BTW it has to be a solid socket wrench / a force bar, not a ratchet or similar toy. The direction | orientation this tool is attached to the socket should be such, that pulling the extender upwards shall be the direction the socket needs to be rotated in order for it to get released / unscrewed.
Between the free end of the force bar extender and the floor, I placed some sort of a solid spacer (a log, a brick, or similar), and made sure this configuration is self-supportive.
Then, I got out from under the car, and started lowering my car very gently, millimetre by millimetre, also carefully observing the behavior of the socket + wrench + extender + spacer configuration.
In this constellation, the whole weight of the car effected the socket rotation, and the O2 sensor just had no other options other than to give in and start unscrewing.
This trick worker 3 times with me, and I never broke anything in this process, BUT you really have to be extremely careful when performing this trick. If you decide to repeat it, please remember that you are doing it at your own risk. If you perform it incorrectly, many things can go wrong, and it can become dangerous.
