Rusted on o2 sensor

Hi, I'm a new owner of a 2000 SR5. New to 4runners but previously had a taco. Pretty happy so far, loving it!

I've been going through maintenance and tune up items since I purchased it like pcv valve/MAF cleaning/tranny cooler install...

My rear o2 sensor failed and I replaced it, I had intended to pull out and clean the fwd o2 sensor as well, but was met with quite possibly the most rusted on bolts I have ever come across. I'm kind of obsessing about it ever since.

Im not sure if the best course of action is to leave it, because it isnt throwing a code yet so I assume its functioning fine and do my best to stop obsessing.

Get penetrating fluid on it for a week or so and try to get the nuts off and replace the sensor and nuts, assuming its in bad shape. My fear here is breaking the bolts off and having to replace the entire section of exhaust including cat because I broke a bolt off doing something that didnt need to be done.

Or just say this entire section of exhaust including cat has lived its life and replace it all...rear of this section is all brand new.

Im in Canada, so its non-cali. Best of my research has the fwd sensor as the same part number as #2. Is that correct?

Any thoughts or tips on how to proceed?

 

Call your local TOYOTA dealer with your VIN. They can lookup the correct part.

On my 2002, they did a mid year change and my car has A/F sensors and not O2 sensors. Only way I got it right was that I called the dealer with my VIN. Even if you don't buy it from them...they will give you the part number.

 

A few months late so maybe you already have this resolved. IMO, I wouldn't mess with it until you get a code. I have a 2002 and replaced both sensors and that got rid of my code so really no need to mess with it yet. Hopefully when the time comes you can get it off okay. I sprayed the heck out of mine a day before I did the job and luckily it went pretty smoothly overall but it was difficult to get the rear sensor off. I can get the part numbers for you but they may be different than yours I believe. No matter what go with OEM, I went with the Denso and my gas mileage went up and no more codes!

 

Yes forward O2 is a different part number. Even Advance Auto shops have them catalogued separately. Here’s mine for comparison....

 

I haven’t tried it yet, hopefully moving out of an apartment and into a place with a garage soon so Ill have a more appropriate space to mess with some things Id like to fix up a bit.

its still in my head though, I know its down there....annoying me.

I believe rock auto has the front and rear sensors on a canadian 2000 as the same part number, Ill call a dealer to confirm but I think they are the same up/downstream.

 

I wouldn’t buy anything from Rock auto..,

 

too late....

 

Get some darn good pentratrating oil (I'm not going to recommend any brand because that will start an whole new discussion ) but anyways I use FreeAll or Trust from Castle Chemical or even Marvel Mystery oil start spraying those rusty threads and let it soak in and do it again and again since you are not in a hurry yet Keep doing it for a few weeks and it may just come apart very easy.

 

You're fine. I buy nearly everything from RockAuto

 

yea in Canada we really dont have a lot of options for parts supply anyway. Ive been happy with everything Ive bought from them.