I am not sure when the last time my o2 sensor was changed, but I got a CEL earlier today on teh way to work. Ran by Autozone and their computer showed an o2 sensor error, so i picked up a new Bosch sensor.

I don't have the correct wrench or tool to remove it, and its pretty tight in there. The largest metric wrench I have is a 19, i think I need about a 21-22 open ended wrench, or something like that.

I tried a pair of pliers to see if I could get it loose, but i started to strip the threads and quit. Sprayed it with a little PB blaster to try and help it loosen up a little. Anyone have a suggestion on how to get it off, which way to turn it, etc...?

I am gonna wait and see if someone can help. I thought there was a how to somewhere but i can't find it with search for some reason.

Thanks guys,

Stu

 

They make a special socket with a slot to remove them with the wires intact, which is also handy to install the new one. I think this is one of the tools you can "borrow" from Autozone (you must pay for it, but they invite you to return it when you're done and get all your money back). Or if you're sure the sensor is bad you can break off the wires and put the proper socket wrench on it. Pliers aren't going to cut it.

 

I did mine a different way
I took off the cat completely and unhooked the plug from the car
I then clamped the sensor on a vice, then rotated the cat around it to get a lot of torque in the movement

 

first off i would unplug the harness plug and see if the terminals are all clean.... it may just be dirty or coroded if you think the sensor is new enough...

but if your POSITIVE the sensor is bad just cut the wires off and get the right size boxed wrench...
you might need to take the header off that the O2 sensor goes into and clamp it on a vise and with the wrench on it just get a pipe to it and man handle that sucker off or if you got a torch heat it up and try again.... the new one can be instaled with a open end wrench just fine JUST BE SURE to use antiseize on the new sensor! try to prevent it from locking up as much if you have to ever change it again hopefully.

or if you dont have a wrench i guess some plumber pliers MIGHT work but i would put it on a bench either way. your going to have to put your back into it!

 

I hit autozone again and told the guy i was removing an 02 sensor, he showed me 3 wrenches they have designed to do it. 2 of them were pretty nice, but the one i bought is basicly just a deep socket with a slit cut out of one side, to let the wires through. I managed to pull back my compressor hose enough to get the right angle on it and slip it over the old one, then a quick bump loosened it right up.

The new one is a little longer, and so is the wire, but its pretty nice they say. I always used Bosch stuff back in the day on my BMW, so I hope it gets me another mile to the gallon, ha ha.

The socket adapter was 8 bucks, a decent buy to add it to my collection. I like to have everything.

Thanks for the info guys.

 

dang.... that is preaty cheap....
did it look messed up when ya pulled it out?

 

It looked pretty charred, if thats the word for it, around the base, in 1 or 2 spots worse then others, and kinda gummed up. I am sure it's bad. My wife said it went out about 2 years ago too, same situation, CEL went on, she had it computer checked and she replaced it and it was fine for another 2 years. It was a Denzo sensor.. This new one is Bosch, maybe it will last.

 

i just went through the same thing. i spent 8$ on an o2 sensor socket which worked great because i already had my manifold off. i put a racing header back on and didnt put the sensors back in until i had everything bolted back together. big mistake!i dont know what model you have, but my 01 civic doesnt leave enough room to get the sensor socket in there, so i screwed them in by hand as tight as i could get them and use a 7/8 open ended wrench to finish the job.