O2 sensor removal

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by anven, Jul 25, 2013.

  1. anven

    anven Member

    Guys, i have been trying to replace my pre-cat o2 sensors and ran into major headache with passenger side one. It seems that the placement of the sensor does not allow any tool i have to get to it. I tried a box wrench, deep socket, o2 sensor socket, crescent wrench... All seem to have zero wiggle room to break it open. Any advice?

    Ps: sprayed plenty of kroil on the sob as well, didnt unscrew itself as kroil would make you believe :)
  2. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    You might need to drop the pipe to give yourself room.
  3. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    Sounds like a saw-zaw and welder kind of job...
  4. j cat

    j cat Epic Member 5+ Years 1000 Posts

    with an open end wrench and the exhaust pipe is hot loosen O2 sensor. then when the pipes cool finish the R/R.

    also if it is really stuck in there place the wrench in ice water then try to loosen. the cold wrench will shrink the sensor to aid in removal. rust is not a problem with these threads/metals.
  5. anven

    anven Member

    J Cat,
    Do you know how I can get a wrench on it? my issue is not rust, its simply not having enough room to get a big wrench in there. I tried dropping the pipe per suggestion above, but it looks like the whole cross-member needs to come out in order to drop this pipe... This should not be this difficult... :) It almost looks like one has to take half a truck apart just to replace one little O2 sensor...

    - - - Updated - - -

    Unbolted the engine side flange, that gave enough flex to the pipe that I was able to bend it down (by hanging my whole body weight on it) enough to get a 7/8 open ended wrench on the o2 sensor. Then I was able to get about a 1/8th turn with the wrench which was enough to break it open. Then using a little 6-inch crescent wrench i unscrewed the rest of the way.

    tough job though - definitely did not expect it to be this bad.

    Thanks for all the advice.
  6. j cat

    j cat Epic Member 5+ Years 1000 Posts

    surprised you have not much room on your model year/engine . ya rust is not a problem as the metals do not corrode.

    what vehicle do you have anyway ?
  7. stchman

    stchman Active Member 2 Years 1000 Posts

    I actually prefer to use PB blaster as a penetrating oil. I put PB Blaster on some pretty rusty exhaust manifold nuts and let them soak overnight. They came off without issue the next morning.

    Have you investigated a type of tool like this?


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