O2 Sensor

[friedk]

Looking for some suggestions. I am trying to get my O2 Sensor out of my 95 Pathfinder. When I get up in there and remove all of the rust around it I cannot seem to find where it threads in. It almost looks like the whole unit it welded in. any suggestions?

[k9sar]

there is a nut welded onto the exhaust and the O2 threads into it. Spray the thing with penetrating oil (PB Blaster works great) and get a good wrench on the nut (part of the O2) furthest from the exhaust.

[friedk]

I see the nut welded onto the exhaust pipe however I dont see a nut on the O2 Sensor. Should it look like there are two nuts... one welded to the pipe and one on the sensor?

[friedk]

Or does the sensor just thread out from the nut on the exhaust. If so will the nut spin?

[k9sar]

it's built like a spark plug. There is a part that goes into the exhaust, a threaded section, a nut-ish section, the main housing and a wire. It is not a seperate nut that will spin off. The entire sensor should unthread from the welded part.

 

[94extreme]

the welded part isn't seen. you just spin the sensor itself.. mine was spot WELDED. definitely look close to see if that is not your case. i ended up destroying the sensor to remove it. good luck.

[k9sar]

hmmm... mine was actually a nut-like thing welded onto the pipe.

[friedk]

I will get under there again and look. To me it seemed that the nut was welded on as part of the bung on the pipe. I could not see where the sensor would screw in/out. Ill let you know if I find anything odd. I assume they are the standard 7/8 or 22mm?

[94extreme]

22mm.

 

k9, there is a bung in there but my sensor itself was also spot welded to the bung.

[k9sar]

nice. can't chance that thing falling out

[94extreme]

well, you know that all that rust around here could have lubed it out of there.. better safe then smart.