Today I decided to replace all three of my O2 sensors. I've gotten codes for all of them. My mileage is terrible, so the pre-cat sensors need to be changed.

Anyways, I was trying to change the post-cat sensor and I realized the size is not 7/8" like a typical O2 sensor, but 17mm!

Do you guys use a 17mm O2 socket to remove it? If not, what have you done to remove it?

 

Your going to need something like this (not me)




And some penetration oil (no homo)

Use an opened wrench that is 17 mm

 

You need to get an O2 socket remover found at any parts store...

 

I have been to all of the hardware stores and car parts stores around here. No one sells a 17mm O2 socket.

I'd use a wrench if I could, but there is no room. The sensor is in a place where a socket is the only thing that can reach it.

A32: Nice joke. Did you use a wrench to remove your sensor? If so, how'd you get the wrench in that tight spot?

 

Try Autozone, they have a tool kit that you can rent for removing the sensors. First, soak the contact points with PB Blaster, it will be almost impossible to remove if there is rust, dirt etc.

 

Love_00_Max,

I have tried Autozone. They don't have a socket that fits 17mm. Does the Autozone close to you have one? If you do, you're lucky. I went to Pep Boys, Autozone, Napa, Checkers, and Sears and none of them have a 17mm socket for O2 sensors.

 

Cut the wires, if your 1/2" deep 17mm still won't fit, (it probably won't), then cut all around the metal about halfway down then use a hammer to bash/break it off, then a socket will fit fine. Don't bother trying to just cut through the entire o2 sensor though, the ceramic is impossible to cut through.

 

I thought of that. However, I don't want to do the same thing when I install the new sensor.

I guess I could always saw off a part of my 17mm socket and try that.

If someone out there has a better suggestion, I'll gladly take it.

 

You shouldn't have to, channel locks or vise-grips will snug it up just fine, getting it out is the hard part. I've had 22mm front o2's that would expand the o2 sensor socket and start to strip it because they were so seized up and I've had to do this before.

 

Well, I tried your suggestion KRZZ350. I also tried my 17mm socket with a cut in it. Neither worked. The sensor is seized up really tight.

I called Nissan here and I talked to a technician. He said he usually removes the whole unit the sensor is attached to because the sensor is too tough to remove. So, I guess I'll just have to replace that part with a new one and then attach the new sensor to that.

 

try some rust remover also on it that should help it out if not replace the piece get the o2 sensor socket with a breaker bar and it should break free

 

The guy that took off my sensor just used a open ended wrench to take it off

 

Have you tried a Sears or homedepot?

 

What do you mean?

I could, but I would have to move some parts out of the way, like the heat shield for the catalytic converter. But that is seized up worse than the sensor, so it's not coming off.

I'll try some rust remover, Lightsout. If not, then I'll just buy a new catalytic converter and attach that. Everything is rusted badly there anyways (all due to the wonderful snow that brings amazing skiing around here).

 

haha, penetrating oil WILL NOT HELP in this situation, at all, zero. I've had really tricky o2 sensors like this. The tech might be right, I've seen ones that weren't coming out without replacing the entire exhaust section it was in OR removing it, drilling a hole and welding in a new bung (not possible in your case w/95-96 style in the cat). BUT that's the last option, what you need to do before that is drive your car around for 1/2 hour (preferably on the highway doing 85mph) and then try to remove it. The last o2 sensor I did was actually not coming out even using the propane torch, this worked, I was just about to give up and I gave one last slam on the visegrips with a rubber mallet and it just happened to turn. Ummmm, in your case if you can't get it out then at least I'll be able to buy your cat off of you I geuss.... But seriously drive the hell out of your car and then do it quickly, dont burn yourself though.

 

Oh and if the heatshield is THAT rotted the bolts will likely snap instantly, if you can't even get a socket on them because they are so rotted than you should be able to pry the fawker off.

 

Great suggestion. I'll try driving my car like that to heat up the exhaust section down there. I'll post the results later.