There's the old saying: "make sure you have the right tool for the job".

I had never changed an Oxygen Sensor before and when doing a full tune-up this week, I decided to change it too. Even though I knew the removal tool size was 7/8, I literally spent two hours on the removal; without success. I attributed this to my engine being TPI with metal fuel lines and brake lines in the way. I was under the hood and I was under the car, but nothing worked short of small increments of loosening.

I next looked at this forum for advice and saw differing opinions. The best one I saw was the one that suggested getting a loaner tool from Autozone, specifically for removing O2 sensors. Thinking ahead, I borrowed both the socket as well as the wrench for removal. The wrench didn't work because there was no room to turn it. The socket finally removed the sensor, but it took at least 50 spins of the ratchet due to tight quarters.

The replacement sensor was by Bosch and is longer than the one that came out. A new problem was now present; the wire end was blocking the square to lock the ratchet into.

Eventually, I figured out that if I had something to grab the end of the O2 socket with, I could remove it. A 9/16 deep socket worked.

In summary, if you have a TPI car and want to have this job done within 15 minutes, borrow a 7/8 Oxygen Sensor socket, put a 9/16 deep socket on it, and after the penetrating oil has sat a few minutes, remove and reinstall.

I'm attaching two photos. One shows the tight quarters the sensor is located in. The other shows how the loaner socket fits over the sensor (the old one is shown) and how the 9/16 socket goes over the end of the 7/8 loaner.

 

I find that O2 sensor socket with an extension up towards the fuel lines makes quick work of O2 sensor removal and installation.

 

12" 3/8 extension on O2 sensor socket plus a pipe on the ratchet from above got it loose without a problem for me!