Trouble Removing O2 Sensor Rx300

[Paul Grappone]

Have the VSC and CEL on...so tried to remove the O2 sensor to clean it to see if that would fix it. Used kroil on the threads and was able to break it loose - but while removing it - it hangs up and becomes very difficult to turn. This shouldnt be that difficult ! Am using crescent wrench. Any ideas?

[Karl K]

Just keep soaking it and turn it back and forth till it's completely free or you'll tear out the threads.

[code58]

Have the VSC and CEL on...so tried to remove the O2 sensor to clean it to see if that would fix it. Used kroil on the threads and was able to break it loose - but while removing it - it hangs up and becomes very difficult to turn. This shouldnt be that difficult ! Am using crescent wrench. Any ideas?

It's galling and you definitely don't want that to happen. It may be to late at this point. What you want to do in a case like that, where once it's broken loose but is hard to turn is to try repeatedly to get the "rust buster" (whatever you are using) in the threads and only turn it back and forth about a 1/16 of a turn or so until it frees up. That way it won't gall and destroy the threads. Trying to turn it when it won't get freeer galls the threads and then with the metal from 2 different parts "marrying", it's all over. Don't you at least have a box end wrench? I would never use a crescent wrench to remove an A/F ratio sensor.

[Paul Grappone]

Thanks folks for your insight - makes total sense. I will soak it up and turn it as suggested. Thanks again !

[missionman]

Any updates Paul?

Im having same issue on my 2000 Lexus RX300 v6 where I got a P1150 code for the upstream o2 A/F sensor.

I broke it loose but then it doesnt want to turn anymore. I cant get it to budge any further.

Im going to get some bolt buster too and rock it back n forth. maybe try some heat.

This sucks man. Ive already had to replace the entire CAT and center exhaust muffler due to the o2 sensor port threads breaking off, now its the threads seized on the upstream o2.

$300 in 2 Denso o2 sensors has turned into over $1000 dollars now due to rusted and various critical threads that are just rusted and siezed to death.

Edited June 16, 2023 by missionman
added info