Hey everyone!! This is not a thread like millions of others in the search history asking "where are the locations of the O2 sensors." This is a specific question regarding what tools make this replacement happen. This is a Fed Spec, OEM exhaust.

I was changing both upstream O2 sensors. I got Bank 1, Sensor 1 done easy with a crows foot O2 sensor wrench.

Bank 2, sensor 1, which is the one towards the radiator above exhaust manifold is a pain in the *** to get too. Forget a 22 mm socket, no room. I also used the crows foot wrench tool with many extensions attached to my 1/2 inch breaker bar and couldn't even really get it on to turn it. If I can, I can tighten it easy, but not open it since I cant turn the ratchet or breaker bar in a counter clockwise fashion since the manifold is in the way.

What am I doing wrong here? Can someone please spoon feed it to me? I bought the crowsfoot since the FSM also says to use it but damn this is just too ridiculous. I just did a waterpump and alternator successfully for the first time but I can't do this??? LOL!! Frustrating!!

Please help me, if anyone has heard or done this.

I greatly appreciate your time and thanks in advance my maximizers!!

 

I used channel lock pliers. A medium sized pair will do the trick. That is if you are referring to the one near the firewall.

 

Thanks gruesome but I already got the firewall side complete.

I'm talking about the one closest to the front of the car, by the radiator, above the exhaust manifold. Bank 2 or Left Bank as it's called, and Sensor 1. It's close to the crossmember and one of the mounts is in the way.

Do I have to remove the member or mount? I highly doubt it as I never heard anyone remove it. More importantly, what tool do I use?

The struggle continues!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!

Thanks again

 

A big wrench or oxygen sensor socket does not work? It should not be that bad. I would not take out the mount, but you could do it if that is your only choice.

 

I'm having the same damn issue! Thank god you were the one to ask. I was afraid to get *****ed at. I've tried twice. I couldn't even get to it with an O2 socket. I bought a 22mm wrench but that didn't help. I'm gonna try this O2 wrench they sell next. The socket part swivels.

 

But... I cannot find that other damn sensor for the life of me..... I can find the one after the cat plain as day but not the middle one.

 

Open ended o2 sucker worked fine on all mine... with the OEM y pipe it's tougher to see but if you trace back from the main cat you'll see the bank 1 sensor 1 on the right side, about even with the axle. Bank 2 is radiator side, forward a bit from bank 1.

Super easy to see if you have aftermarket y pipe, a bit harder if OEM

 

If you have an O2 sensor after the cat, that means that you have a Fed spec car. There are only 3 O2 sensors on fed spec: One right after each exhaust manifold and one after the catalytic converter.

 

And for some reason I cannot find that middle one. I can only find the one up front, that connects right above radiator. I really wish I didn't cut the wires thinking I was going to be successful today.

 

Done!!!

Ok there is a o2 sensor kit at autozone for rent for 25 bucks deposit. So its free in other words. There are 2 size crowsfoot sockets and a reg socket all 22 mm. The smaller of the 2 crowsfoot sockets worked great. Also rented a wrench that has a curved handle with a swivel on the socket. Its made for o2 sensors and its says its for ford cars but it also worked great. So get both rentals at AZ since you will use both. Why both? The crowsfoot has a nice hold on the sensor to loosen it but I couldnt tighten it back up so then used the curved wrench. Just be careful since it swivels u want the socket portion flush on sensor before u put force on it.

Oh I pb blasted for 3 days and tapped them with a hammer before taking them out. Came out like butter!!! PB blaster is the secret weapon!! Unless you wanna strip it or use heat and fudge something else up.

 

Aburn95 we're in this together brother. Good luck and lmk how it goes!!

 

Thanks man! I'm going back for both the tools tomorrow. I need my $27 back!

 

Dumb question.... I was under the impression that cali cars had four sensors, and the rest three. Is that not true? Do some only have the two?

 

You are correct. Cali cars have 4 O2 sensors, a sensor right after the exhaust manifold and another sensor after each of the pre-cats. Cali cars do not have an O2 sensor after the main cat. There are no Maximas with only 2 sensors (at least 4th gen and newer).

 

Ok thanks Dennis. I'm done with noob questions in this thread.

 

BTW, I've purchased both of mine off ebay for $22 each. They are Bosch parts that you get at Autozone for $80.

 

Channel lock pliers worked for all three on my max. If you are chucking them, tooth marks don't really matter

 

O2 sensor socket on with adjustable wrench got mine off pretty easy. Could not ratchet it but just the socket and the wrench on the hex part gave me the play in the angles to get both my upstreams done. Locking pliers probably would have been easier now that I think about it though.

 

Just did all 3 of my o2 sensors last weekend. Front one is fairly easy once you get the o2 socket on it then a wrench on that. Rear is really easy to get to, it's just getting the wire out that's a royal pain. Worst one was the one after the cat, it was stripped. Threads in the cat were ok so popped the new one in. I'll be watchin to see if my mpg improves any now that them and the alternator have been replaced.

 

Thanks for this Picture, now I kno I have a 95 fed spec car, but the last o2 sensor after the cat seems To be smaller then the 2. Upfront sensors I dont think its 22mm. Check engine light has been on and Ive tired To remove it with no luck, sprayed sum wd-40 on it but havent bothered with it since. I removed the other 2 sensors rad side with a 22mm wrench, and firewall side with a sensor socket.

 

sensor socket worked flawlessly on my 99SE fed spec for that one behind the cat. Needed a pipe as extension though, was a biitch to get off, even after pb blaster

 

Just needed To be sure that the rear o2 sensor after cat is the same as the other 2, is it 22 mm?

 

I have a Nissan Maxima 2013 and I need to replace Bank 2 sensor 1. Is it located in the front? If I want to order the part, do I need to order upstream front or downstream front? Denso 234-9036 is a right one?

 

Bank 1 = firewall side
Bank 2 = radiator side
Sensor 1 = upstream
Sensor 2 = downstream

I leave it to you to verify if the Denso sensor is the correct one.

 

Thanks for the help. I was wondering if any issue happens if I do not change the sensor?

 

it will set a code. which is a problem or not,depending on where you live.

you will get bad mileage. the extra gas can roast the cat.

replace it. soon.

 

I used a standard 22mm crowfoot. NOT the ones sold as "oxygen sensor wrench"

Get one of these

Not correct.

The post-cat o2 sensor "downstream" nut is smaller, at least for 95-96 models. I think it's 12 or 14mm,not 100% sure, btu I know it's not the same 22mm as the upstream sensors.

 

it is possible to remove stuck ones by whacking them on the side till the end breaks off. once it does, slip an ordinary socket over the stub. a considerable amount of force can help remove what's left.

 

I have replaced O2 sensor. Does the alarm go away right after replacement or I need to reset something or maybe it takes some time?

 

It will reset eventually if you do nothing.

But if you are in a hurry for state inspection, you could either clear the code with a code reader, or disconnect the battery overnight.

 

I drove around 90 miles and did not disappear. However I am not in a hurry, do you think I need to drive more?

 

It takes several driving cycles.
It needs to heat and cool.

Just do drive normally. One driving cycle, even 90 mIles will probably not clear the code.