Last week I tried pulling the O2 sensor off my New Beetle and I nearly sheared the damn sensor off, and bungled one of the points on the sensor in the process. I regrouped and bought a couple sockets off of Amazon, but they didn’t even fit on. In the end, here’s what worked:
1. Using MAPP gas heat the bung, the female threads holding the oxygen sensor in place, for 70 seconds.
2. Clip the wire off the old sensor and place a 12-point 7/8-inch box-end wrench over the sensor and pull.
That’s it. The sensor required some strength to break it free, but then it came out pretty easy. I was tempted to spin it with my fingers, but be careful as it will retain heat for a good ten minutes after heat was last applied. To reinstall the new sensor (I bought a cheap one on eBay marked 050558 000025-050558 613234-21-05 and Made In China):
1. Apply anti-seize lubricant (Permatex 133A – 81343) to the oxygen sensor’s threads.
2. Apply AGS dielectric silicone compound to the electrical connections on the oxygen sensor and the car.
3. Thread the new sensor into place and snug up with a good tug on a 7/8-inch open-end wrench (I don’t have a torque wrench to apply 30 pounds with, so I estimated).
If this cheap sensor performs I’ll pick up another for front side of the catalytic converter.