For O2 sensors BUY THE OFFSET FLARE-STYLE WRENCH.

https://www.amazon.com/TEKTON-47749-8-In....

That bastard right there.

DO NOT BUY THE GARBAGE ONES AND DO NOT TRY TO USE AN OPEN END WRENCH!

If you round off the hex on the sensor you're FUCKED and may have to drop significant parts of the exhaust or even the header to get it out. Buy that tool, spray around the threads with penetrating oil, START THE ENGINE for a minute or two to warm the threads and pipe up and then (careful you don't burn the shit out of yourself!) use THAT to get it out. That tool goes OVER the wire and like a flare wrench prevents buggering the hex when trying to loosen it, and can take a nice 3/8" breaker that has a swivel on the end so if the angle is fucked up (and it frequently is) you can still get to it.

Its a literal $11 and I've never had one that won't come out trivially using it, even if its original and has been in the car for 20 years. Don't be a cheap asshole and fuck yourself.

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