Removing an obstinate O2 sensor?

Boomyal

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I am trying to help my not so mechanically inclined Son In Law remove a downstream oxygen sensor. From his picture it appears to be mounted in a cast exhaust pipe flange, just below the catalytic converter. He borrowed a one piece socket wrench from autozone and has the car up on ramps, so being a transverse mounted I4, everything is out front of the wheels. Still, he has limited clearance from the floor. I have suggested several tricks. Use penetrant oil, use an upside down computer air can to chill the sensor, get a 3 lb sledge hammer to rap on the wrench handle and/or get a piece of galvanized pipe to slip over the wrench handle to increase the leverage. I have also suggested that he find a curb somewhere where he can set the ramps on the edge of the curb and hang the front end out over the lower street.

Can anyone add to these various techniques and tricks.
 

MTboatguy

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You need to heat it up, unplug from the harness and take a propane torch to it, get it good and hot, then watch yourself and unscrew with the wrench, I would also suggest soaking it with P-blaster and let it sit for an hour, then heat up and try, be careful as the blaster will catch fire. Shrinking won't work as it is the heated rust that is holding it in.
 

Boomyal

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You need to heat it up, unplug from the harness and take a propane torch to it, get it good and hot, then watch yourself and unscrew with the wrench, I would also suggest soaking it with P-blaster and let it sit for an hour, then heat up and try, be careful as the blaster will catch fire. Shrinking won't work as it is the heated rust that is holding it in.

Are you saying to heat the sensor, not the surrounding flange?
 

MTboatguy

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You need the heat the flange and sensor, to break the bond the rust has created.
 

bruceb58

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Best to try and heat the exhaust but the reality is the sensor will get a lot of the heat as well. I would first let a penetrating oil like Kroil sit overnight first.
 

dolluper

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Run the car get it hot and a pipe wrench....add extra heat if needed while trying to remove
 

foodfisher

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Had a similar problem. Took it to the mechanic. That's where I learned about PB blaster.
 

MTboatguy

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PB is the only thing I use now a days, I have not seen anything that works as well as it does.
 

MTboatguy

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The Machine shop my Dad helps out at, won't even let Kroil in the door anymore, they said they have changed the make up of it so much, it is not effective any more. When it comes down to it, we all use the products(s) that work for us based on our experience, PB continues to work for what I want to do, so no need to change right now.
 

bruceb58

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The Machine shop my Dad helps out at, won't even let Kroil in the door anymore, they said they have changed the make up of it so much, it is not effective any more. When it comes down to it, we all use the products(s) that work for us based on our experience, PB continues to work for what I want to do, so no need to change right now.
I guess that's possible with then not allowing certain solvents in things anymore.

Funny thing is I switched from PB blaster to Kroil after having the same issue...stuck O2 sensor.
 
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MTboatguy

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That rear O2 sensor can be a real pain in the rear to get out on certain models of car, I know my Jeep was something, it was mounted so close to the convertor that the heat and cool cycle basically welded that sucker in there.
 

bigdee

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The Machine shop my Dad helps out at, won't even let Kroil in the door anymore, they said they have changed the make up of it so much, it is not effective any more. When it comes down to it, we all use the products(s) that work for us based on our experience, PB continues to work for what I want to do, so no need to change right now.

Yes we had issues with kroil too. It was more of a solvent than a lubricating oil,in fact it would dry out bearings. Old timers used a mix of #1 kerosene,ATF and MMO.
 

bruceb58

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Why would anyone put Kroil on bearings? And yes, Kroil is a solvent!:facepalm:
 
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Scott Danforth

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both PB Blaster and Kroil are solvent based and not intended for anything other than freeing stuck things.

for stuck O2 sensors, unless the sensor is buried in a well, skip the socket for trying to remove it. I use a box wrench. a few times I had to knock the sensor off or cut the wire, however I have been able to get out every one. a few of the O2 sensors buried in a well required busting the sensor out and putting in a turned-down impact socket. I have a 7/8" (22mm) sensor socket for installation, and a two7/8" box wrenchs with the open end cut off so I can slip a piece of pipe over it for removal. one I bent on the break press at work to fit in on G-ma's old Crown Vic
 

bruceb58

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for stuck O2 sensors, unless the sensor is buried in a well, skip the socket for trying to remove it
I agree. The special O2 sockets have slots in them that allow the wire to pass through which just weakens them. Just break the sensor housing off and use a short socket.
 

dolluper

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Haven't seen one yet that I cant get out with a pipe wrench..those special sockets are only good for installing the sensor that's all
 

MTboatguy

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By the way, so you don't go through this again, use some O2 safe anti seize thread dope. Don't put it in dry, if he keeps it long enough, you will go through this again.
 

Boomyal

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Haven't seen one yet that I cant get out with a pipe wrench..those special sockets are only good for installing the sensor that's all

I'd agree with you but I do not think there is any room to get a pipe wrench on it. That aside, I am not there in person and am trying to help from a half a continent away.
 

bigdee

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Why would anyone put Kroil on bearings? And yes, Kroil is a solvent!:facepalm:

Leave a can laying out in an industrial plant and you'll find out! That is why we banned it and personally I never had much of a need for it.
 
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