When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Old thread? who cares..
I know that some folks get all upset when an old thread is resurrected but I look at it this way if the info can help someone then it should not be a big deal. I think it's better than starting a new thread about a topic that has already been posted to death.
One of my sensors came off with no problems so I had the hardware replaced-with anti seize compound). The other needed to be grinded off and new studs had to be installed(which was done at the dealership with gray hair) had I listened to the kids there I would have needed a new exhaust- which i did think about briefly.
I just came from the dealer the other day this time it was a new starter
I guess I'm lucky in that my nuts and studs were not rusted at all.
Before removing the front sensor on my 2001 Tacoma, I did soak them with PB blaster, but they weren't coroded and came off without much difficulty.
The problem that I encountered was that the threads on one of the nuts was boogered up and I couldn't get it back on either of the studs.
I picked up a stainless nut from Fastenal to replace it, but couldn't get it to thread on either.
In reading about replacing the nuts, I've seen some say they are M8x1.25 and some say they are M8x1. The nuts that I tried were 1.25 and with the problem I encountered, I have to think that it's either the wrong thread pitch or the threads on the stud were messed up somehow.
I'm pretty sure it's M8/1.25. If they don't fit I'd suspect the threads on the studs. Use a properly sized die and chase the threads to get them lined up again. The threads can take a beating when trying to get the nuts off. But then you had no problem with that.
Have you solved the problem? Is the new O2 sensor back in?
I'm pretty sure it's M8/1.25. If they don't fit I'd suspect the threads on the studs. Use a properly sized die and chase the threads to get them lined up again. The threads can take a beating when trying to get the nuts off. But then you had no problem with that.
Have you solved the problem? Is the new O2 sensor back in?
I haven't fixed the threads and put a nut on the stud yet, but I did rig up a temporary solution so that I wasn't driving my truck with no o2 sensor. I drilled a hole in a hose clam and fitted that over the stud, then tightened it down. My cel cleared itself after a few miles, so everything is good for now. Guess I need to find the right size thread chaser and get things fixed back up.
code came up for bank 1 sensor 2, will I harm anything if I drive like this for a couple of weeks, before I change it ??? by the way EXCELENT wright up !!!
I think you can drive on that for a while. The sensor 2 is the downstream one which I think just basically tells the ECU that the cat is working correctly. The sensor 1 gives signals for proper air/fuel ratios.
Others chime in please and correct me if I'm wrong. Don't want to give false info.
Replacing it is a PITA but not hard. And afterward you're good for another 120K.
code came up for bank 1 sensor 2, will I harm anything if I drive like this for a couple of weeks, before I change it ??? by the way EXCELENT wright up !!!
Thanks Durk, & Up & Down, there was another code PO125, but I was low on antifreeze, hope that's all it was ...Pete
P0125 is usually not a cooling problem, It suggests a front O2 issue that is keeping the ECM in open loop (start-up) mode which kills MPG and reduces power as the engine runs rich. Also not good for your cats. Change that sensors and likely all will be well. You do not want to leave this condition as you can ruin a perfectly good cat by sending unburned fuel down the pipe.
I think what happens is the ECM compares O2 and ECT sensor readings and decides one of them has to be wrong. For some reason, it believes the faulty O2 and decides it needs to stay in open loop and sets the P0125. Check your coolant temp with a scanner to really see what is going on and whether you are stuck in Open Loop.
I just did the air/fuel ratio sensor and downstream oxygen on mine this week. But I did not know that my 4runner was a California emissions type until I was underneath and the sensor wiring was too short to hook up. Had to look on multiple forums to read about looking under the hood to see the label and mine said applicable to California somewhere.
Thank you rjkjoe for this and the pictures! For months I was looking at this for inspiration that this could be done. I tried several months ago with getting those rusted and partially gone nuts and yes, considered torching it or even trying a heat gun. Turns out PB, locking pliers or a 12mm box-end wrench and mallet would free those nuts. I enjoyed the whole experience I said screw the anti-seize, I'd do it again 10yrs later, bring it on.
For mine, I had to reset the ECM -- I thought the CEL would go off automatically soon after driving some miles, but it didn't. So far it hasn't come back (!)
Last edited by 75w90mantraN; 05-04-2014 at 03:47 PM.
I have discovered that the best way to remove totally rusted Oxygen sensors is to score the nut with a cutting or grinding wheel. This will help loosen up the nut and it can then be removed with a vice grip pliers. It worked well for me today. The stud that the rusted nut was attached to was still in perfect shape once the nuts were removed. EASY PEASY>
I had a friend who was a Cadillac mechanic and he taught me a surprising thing about exhaust antiseize; the best is Permatex, setting. It forms a film that will hold, but will prevent the galling that freezes fasteners together.
Thank you, I was expecting the same rusted out condition on my 1990 delux extra cab v6 pickup. I lucked out and was able to remove the old sensor. I’m headed to Home Depot in the morning to get new stainless steel nuts. Now that you have given the size I should find them quick. Update!, added a picture of the old sensor and new sensor.
Replaced with Denso part
Last edited by Boboso; 02-16-2020 at 09:27 AM.
Reason: Add pictures
Been through everything discussed changing the sensor. The studs broke off during my attempt. Anybody else have this problem? Any suggestions on a fix?
New here. Thanks for the tips from everyone. Figured I’d add my 2 cents since I didn’t see anyone mentioning this. This process works well except with the heat sheild in place and the o2 sensor still in there, there is no room to turn the needle nose vice grips. If you use the 7/8 (22mm) offset O2 sensor socket to loosen and remove the sensor first, you will then have plenty of room
to get ahold of whatever but is remaining. Mine had almost no nut left at all. I soaked it with Pb blaster a couple times then waited a day and a half before getting in there. Worked great. Rusted nuts and gasket from 2000 tundra O2 sensor. Bank 1 sensor 2 (downstream)
Originally Posted by rjkjoe
This is a simple post on changing your O2 sensor when you look at the nuts and wonder....how in the world am I going to get those off!!! lol This job was done on a 1997 4 Runner SR5. These instructions can be used for either sensor. For those who don't know where an O2 sensor is located, crawl under your vehicle under the front passenger side door and find your exhaust pipe. You will see the catalytic converter on the exhaust. It has a heat shield on the bottom of it with holes all over it. On either side of the converter you will have an O2 sensor. (Look for wires going to the exhaust pipe) The upstream sensor (Bank 1 Sensor 1) is toward the front of vehicle. The downstream sensor (Bank 1 Sensor 2) is toward the back. Attachment 185253
These are sooo rusted you can actually see the threads of the bolt stud.
First off, I recommend soaking the nuts in some sort of penetrating oil for at least 15 minutes. I used PB Blaster. It works extremely well. Then I used a small pair of vice grips and gently but firmly locked onto the nut and slowly removed it.
After you remove it, it's time to unplug it. There is a push tab on the back of the plug attatched to the vehicle. Just push it firmly and pull. You might use a small set of pliers here to make sure you're pushing it hard enough. Mine came out without pliers though.
Once you get the O2 sensor off you can then start cleaning the surface area that the new sensor gasket mates to. You will have to remove ALL of the old sensor gasket which will more than likely be rusted to the mounting surface. I used a paint scraper to scrape it. I also used a wire brush and metal file to remove the old gasket. This is the most time consuming (at least for me) part of the job. It took me about an hour. I wanted to make sure I had a smooth mounting surface.
If you stick your finger into the O2 hole it should feel smooth and you shouldn't feel a lip around the hole. The mounting surface should be completely flat. You have to use your finger feel the mounting surface because you can't see it that well. A small sharp chisel would work well here but I didn't have one so I improvised with a small dull knife. Once you are happy with your mounting surface you should clean the threads of the mounting posts with a thread cutter. M8x1.25 is the thread count and size. You will need this when you buy the replacement nuts and lock washers. After I was satisfied with the mounting surface I cleaned it with a rag soaked in Isopropyl Alcohol (rubbing alcohol).
Next just install your new O2 sensor and tighten it down. Make sure you put anti-seize on the studs.
Once you get it installed it's time to plug it back in. I used some dielectric grease and kinda forced it into the female plug holes just for good measure.
Once it is plugged in, if you didn't buy stainless nuts, I would recommend coating your new nuts and washers with the anti-seize to help keep them from rusting.
And there you have it! If you were changing it due to a thrown code, your engine light will go out after a few miles of driving! Hope this helped!! And finally, here is a pic of the nut I removed;
03-30-2016, 11:17 AM
I find the easy way is just cut the studs off.
