This was a great write up. Followed it to a t and it turned out great, even ordered extra nuts for the good sensor and installed them so I wouldn't have to fight with the rust next time. The torch method helped tremendously.

 

What size nut do these O2 sensors need? I would like to go buy them have them ready when I change mine out. Thanks!

 

I think 8x1.25mm. Where is the part number for the brass nuts?

 

The stock nuts are stainless M8x1.25. Part No. 90179-08059.

 

Hello,
I hate to have to reply to such an old post..My time has come to perform this task. i have the code P0136 which points to a bank 1 sensor 2 fault. I have already purchased the sensor. I just have one question when i am under the vehicle there are 2 Sensors one closest to the rear of the truck and one closest to the front. I think that i want to change the one closest to the front of the Vehicle, but i am not sure.

I know that after reading such a detailed write up and on the same truck it should be easy.. i am just looking for confirmation.
Thanks

 

Sensor 2 is the sensor farthest from the engine. After the cat.

 

Hey,
Thanks for the reply... I saw diffrent readups which pointed to the one closest to the engine... but if it's the other one then i might be in trouble there are no nuts or threads to speak of to remove it... i'll have another look at it and see where i sit...
Thanks!

 

I could be mistaken, but isn't upstream and backstream o2' sensors different part #s?

 

Hey,
I think you might be right
She has to go back to the dealer for other work that is beyond my scope. I have the receipt and if i did infact purchace the wrong part i can always exchange it for the right one and for $100 they will cure the problem once and for all. betcha when i get it back i'm going to crawl under there and see for sure.

 

Thanks, good write up.

 

I knew I forgot to do something.... I forgot to update my situation... basically to be short and sweet... I knew that I was not going to replace my exhaust system and as bad as my bolts were rusty.. I thought that was my only option. I went to another dealer to see what could be done... when I told them what the other dealer told me was my only option. An older tech who was changing my oil drilled and tapped the pipe installed the new sensor I bought and did not charge me. When I have to go back for the Valve cover leak.. I was told to come to him. Never have I ever had such great service from any other dealer Ford nor Chevy. for this dealer to look after me and my 97 like this was truly refreshing. it's like when I get on a plane... I like to see some grey hair on the pilot same goes for the tech too..

 

Just saw this thread after replacing the front sensor on my 2000 4Runner 4wd for the first time. Where are y'all driving that causes so much rusting of bolts? My bolts are pristine after 250,000 miles.

 

Hey There,
Winters here in NY will do that to an undercarriage. you saw the pictures.. I lucked out and found me a tech at the dealership who knew how to deal with such crap. I'm just glad that I got it sorted.. next up... valve cover leak.

 

I assume they salt heavily in NY in the winter? I guess we are lucky CO doesnt use salt.

 

SALT????
IT'S ACID!!! pure and simple!!! and in the spring we get potholes the size of small children! I am not sure of what the exact mixture is but it's poison for any undercarriage... Ive seen same vintage cars from your neck of the woods and on the extreme west coast.. I cannot belive they are the same year!

 

PITA..... Replacibg mine now...

The bolts are f up. Soaking in PB BLASTER RIGHT Now

 

I feel your pain ... what you should do is when you get em off.. is to coat them with some Anti seize compound and every once inna while inspect them. you might even replace the hardware . I did just that. so far so good.. mine were pretty rusted on. sadly, I had to go to the dealership and luckily found a tech with some grey hair... best of luck!

BTW that PB BLASTER is some fine stuff!

 

Well no good, ima take it to my local toyota fabricated and have them take a look.

 

no foolin? when I first tried I had to let them soak for at least a day.. then after that I tried... my tech was able to re tap the studs and off I went. I bought the gasket and the sensor all he had to do was install..
Good luck

 

I know this is an old thread but I just wanted to say thanks and add a quick tip for those without a torch (butane, not a flashlight all you Brits). Use the heat of the exhaust.

Hose the nuts down with PB and take truck for a drive to get the exhaust hot. Park it, let it cool. Start trying to get a grip on those nuts and unscrew them. You might get lucky. Mostly what will happen is the loose metal and rust will create a kind of slurry on the nut that makes it hard to get a grip. Grind it all off with pliers etc. Then take a steel brush and clean them really good down to metal so there is no rust left. Hose them again with PB and take it for a drive to get exhaust hot. Park it and let it cool. The cooling off will draw the PB in. Grip those @#$%*&^ and twist them off. This has worked for both of my O2 sensors.

And yes, get ready to spend a lot of time cleaning the gasket surface. Invest in this. It ensures only having to do this job once and hopefully not again for another 125K.