removing a rounded off oxygen sensor

[ryan roopnarine]

hi all. i tried to remove the oxygen sensor on my 92 m50 equipped vehicle with an oxygen sensor wrench/crowfoot, and found that i rounded it down significantly. after hitting it for about five cycles with a blow torch followed up with a soaking of pb blaster, i tried to remove it with a 22mm deep socket and breaker bar, and found that it only made the rounding worse. i also tried turning the body of the sensor with vice grips and a breaker bar, marking the position of the sensor relative to the manifold with a stripe of paint, and found that i only manage to twist the sensor body, and not budge the sensor nut any. is there anything else I can do, or do i have to put in a new hole? I was thinking about using a pipe wrench, but i don't want to screw up the nut anymore if there is another measure i can take. thanks.

[Blitzkrieg Bob]

Try heating just the bung on the manifold and use a chisel and hammer to knock the sensor counter clock wise.

You could cut the sensor down to the nut to get ready to weld on a bolt and try to go from there.

[ss2115]

hi all. i tried to remove the oxygen sensor on my 92 m50 equipped vehicle with an oxygen sensor wrench/crowfoot, and found that i rounded it down significantly. after hitting it for about five cycles with a blow torch followed up with a soaking of pb blaster, i tried to remove it with a 22mm deep socket and breaker bar, and found that it only made the rounding worse. i also tried turning the body of the sensor with vice grips and a breaker bar, marking the position of the sensor relative to the manifold with a stripe of paint, and found that i only manage to twist the sensor body, and not budge the sensor nut any. is there anything else I can do, or do i have to put in a new hole? I was thinking about using a pipe wrench, but i don't want to screw up the nut anymore if there is another measure i can take. thanks.

LOCKTITE have a new freezer spray that you spray the same way as you do WD40.
As it minutely shrinks the bolt (your sensor) the lubricants are supposed to wick into the threads and provide lubrication.

Its new and I haven't tried it. But its in the trade magazines as better than WD40 type sprays that rely on soaking penetration.

Good luck.

[ryan roopnarine]

LOCKTITE have a new freezer spray that you spray the same way as you do WD40.
As it minutely shrinks the bolt (your sensor) the lubricants are supposed to wick into the threads and provide lubrication.

Its new and I haven't tried it. But its in the trade magazines as better than WD40 type sprays that rely on soaking penetration.

Good luck.


i used up a whole can of CRC's freezing penetrant on the fitting with no effect, so I doubt that locktite's offering will do much better.

thanks though.

[yaofeng]

Remove the cat to do it on the bench. I am a pessimist.

[bubba966]

Remove the cat to do it on the bench. I am a pessimist.

+1

I tried pull the O2 on a '95 M50B25TU (should have the same exhaust pipes as yours) with the exhaust in and I couldn't get it out. Dropped the very, very f'in heavy exhaust and was able to get it out once the exhaust was out from under the car.

I'd drop the exhaust, grab a pipe wrench, and go to it after heating that thing up cherry red with a torch. But trust me, you can get much better angles and much better leverage with the exhaust off the car.

[Ross]

Add my vote to the pipe wrench idea. Brute force and fire are your friends now.

[Kibokojoe]

I second that. Drop the exhaust and fire it up. If you don't have acetylene I would use mapp gas and pb blaster. If the sensor breaks then drill it and use an ez out.

[Tiger]

Big fat Vise grip (not needle nose vise grip) on the the O2 bolt... First, make sure you can grab it easily enough so you don't fumble when trying to grab it while it is hot. Then remove that vise grip.


Torch that O2 sensor until you see the change of color in the flame... WIth propane, it might take about a minute... MAPP is faster... but whichever you have is fine. The longer you heat it up, the better chance of getting it out.

Once the O2 sensor is hot, put the visegrip on it and bang it loose.

If you put the visegrip on the O2 sensor, you are dissipating that heat so you can't get it hot enough regardless how long you heat it.