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      11-11-2012, 02:23 PM   #1
signes
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Help with stuck O2 sensor

In the midst of swapping out my x-pipe and having trouble with the front O2 sensors. I was able to separate/unclip the rear sensors but having trouble separating the fronts (probably being too cautious, just don't want to break the them.) That led me to try and unscrew the sensor from the pipe (working under the car on stands so hard to get a lot of leverage) and seems to be locked solid. I don't have a torch handy, any trick to breaking these loose? Or any tip to separating the front sensor clip? Thanks.
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      11-11-2012, 04:26 PM   #2
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The front sensors are just clipped on. Really easy to take off. Depress the edge of the cupeling (sp?) and just pull. Additionally, you can take a big wrench and muscle the sensor off. Once it moves a tiny bit, your good and slowly unscrew it. However, get a flash light and look really careful at the connector to the car and try to unclip it that way. It's really hard to unscrew the sensors with then still attached to the car; possible, but it's a pain.

Also, get yourself some anti seize grease. I forgot what it was called but at autozone it's in a small grey plastic can. It will help with future installs
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      11-11-2012, 04:30 PM   #3
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If your talking about the rear O2, which is the one farther from the engine, which it seems like since the front are really easy, you have options. A: take two really really small flat head screw drivers and wedge them in between the two retainers on the coupling. Then pull. B: Huge wrench and leverage. When you go to put them back on, twist the wire again and that will make reinstall way easier.

Anti seize comment still applies.
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      11-11-2012, 05:01 PM   #4
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On the front driver's side, you have to remove a little triangular brace. I think it has two 10 mm bolts, one of which is a little awkward to get at. Once that is removed, you can unclip the harness and move it a little so you have better access to it. Then you can study it to see how the two halves come apart. They do come apart, but you have to study it to see the tabs.

The passenger side front is easier. There is no metal bracket to remove, at least on my 6MT car. Unclip the wiring and then undo the harness connector.

I agree about not twisting them loose with the harnesses connected. The edge of the top of the 02 can cut the wires. Also, twisting wires that tightly is not good for them when they are in a harness like that. It can be done, however, once or twice, and you will probably get away with it if you are careful.

As for the sensors being frozen in the pipes, I would not use heat since you could damage the sensor. I would spray with penetrating lubricant like PB Blaster or Kroil or Thrust. Use an 02 socket (has a slit for the wire) if you find one that fits. I usually use a 22 mm wrench. You have to use the open end, obviously, because the harness connector won't fit through. Once you have figured out the lefty loosey righty tighty bit and know what direction to turn, you can hold the wrench end on the socket while you whack the other end with a small sledge hammer. Often a quick shock is more productive than massive muscling when it comes to freeing a frozen bolt (though with old rusted frozen ones you can break the nut or bolt top right off doing this and MAPP gas or Acetylene is best if penetrating oil alone does not work).
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      11-11-2012, 05:04 PM   #5
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are you using an o2 sensor wrench?? should come out somewhat easily...but you definitely need the right leverage
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      11-11-2012, 05:34 PM   #6
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Thanks all, very helpful. I have a 22mm wrench (a long one) but still wasn't budging. Will have another go at the clips, I can see how they work but just seem stuck.

Pbonsalb thanks for the tip on the drivers side. Was wondering if my early 08 was different. Also thanks again for the tip a while back on the flex head wrench for the header bolts, worked like a charm.
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      11-11-2012, 09:52 PM   #7
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Also, get yourself some anti seize grease.
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      11-12-2012, 11:04 AM   #8
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Put some copper anti-seize on before putting them on the new pipes. Once I had the pipes off it was quite a bit easier but needed a lot of force. Being 20 degrees out didn't help...

Thanks again all.
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      11-12-2012, 03:23 PM   #9
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I used some liquid wrench on them. Then I used a crescent wrench and a hammer to get them moving. Tapping lightly on the wrench with the hammer helped a lot (especially under the car) but you have to be very careful not to ruin the flats on the sensor.
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      11-12-2012, 03:35 PM   #10
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I noticed they seemed a little soft which is why I backed off a bit. Once off the car, they were easier to deal with but still needed a lot of grunt to move. Same for the header bolts. Going to buy some PB Blaster/liquid wrench so i have it on hand next time.
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