O2 sensor ground, is it rusty? Make it easier to remove for the next guy....that might just be you.

**Sept 22 update:
Original article:

O2 sensors being grounded by the exhaust, is a concept for 1 wire O2 sensors. 4 wire O2 sensors are wired with their own ground and are not grounded by the exhaust.**

I hadn't thought about checking if the O2 sensor was cleanly grounded. Cleaning up rust always helps O2 Sensor Mod and Diagnosis)with a good connection. Yes, anti-seize. When I was early DIY rather than nearly a technician I installed a new O2 sensor, up river, and got my 1999 Chevrolet Prizm running nicely again (same as 1998-02 Toyota Corolla). The Chevy wasn't that rusty then. Now....until I own an acetylene torch or replace that manifold that O2 sensor better not fail. So rusted in (I can't take the down pipe off my manifold until the oxygen sensor is out of the way. Thankfully just replacing one of the springs cleared the exhaust leak ...still wanting a new doughnut gasket in there, but don't fix what isn't broken, it runs soooo much better). . . So yes, use anti-seize but don't get any on the sensor! (8/23/15 update: The aftermarket Bosch oxygen sensor appeared to have a normal oxygen sensor socket install, but it actually includes a flange with 2 bolts. It's an interference fit with the down pipes. I've made a video with the solutions! I got back to a OEM Denso which you can see doesn't have a nut next to the flange, which confused me into believing it wasn't removeable.)

Anyway, I just meant to say that only 8 years ago I installed the Bosch oxygen sensor and I wish I knew to put in anti-seize. The rust really isn't that bad but it's enough. I destroyed my harbor freight oxygen sensor socket...may have already done that a few job's ago that I worked around not removing the oxygen sensor. I now have a much more expensive Powerbuilt socket (never in water, quickly rusted. :p - got it super cheap on Amazon, maybe it was a Powerbuilt knock off). I haven't bought a lot from them, but whenever I break an inexpensive tool, I replace it with this brand and I never have a problem again. My new Powerbuilt O2 sensor remover worked brilliantly. It's removing all the oxygen sensors that I thought were rusted in badly, almost easily.


The last Bosch oxygen sensors I installed on my mom's 1999 Mercury Sable ran okay...but with them all new it ran sooooo much better (Same as 1999 Ford Taurus). I was surprised that the down river O2 sensors helped it run better....I guess the car's willing to run a little richer for some punch when it's not dirtying the environment? I might have imagined that part of the improvement. Bosch includes the perfect amount of anti-seize on the O2 sensor threads now. I had to love them for that little touch.

And remember, don't blame an oxygen sensor or a catalytic converter for an exhaust leak. I have a live scanner now and my new cat gave me 50% more horse power (possible to find out using a torque app and some open freeway, gps confirmed *HP as long as you report the weight of your vehicle accurately) and almost removed the condition of the rear oxygen sensor voltage switching up and down too quickly. That shows on my live scanner ...sign of a bad cat? Sure. The catalytic converter does a lot better, but you can't have an exhaust leak before the cat and know for sure if that cat is really bad without checking upstream before you finish your diagnosis.

The old catalytic converter nearly showed the same reading before and after the catalytic converter indicating that it was almost doing nothing for the car. Need more analysis for how O2 sensors should be running? Check out my article and video on the subject. Here's a link to O2 Senors, The 4 Stages of Death.

by AutoBravado