I am having trouble removing my post Cat O2 sensors. I have a solid 22mm wrench that is made for removing O2 sensors, and I soaked well with PB Blaster and heated up the sensor before hand, but when I tried to wrench it off it just rounded sensor's plug bolt sides.

Any help is appreciated.

 

OEM/Oxygen sensor wrench (27162) | Oxygen Sensor Socket | AutoZone.com

thats the one i used to get mine off, its no solid.

i say use more pb blaster and let it soak a few days then try again with stuffing a latex glove or two around the sensor then put the wrench on and give it a shot. that has gotten me out of a few roundings.

 

I bought two different special wrenches and a crow foot wrench, heated the bung cherry red using two blowtorches, and was able to remove three out of four O² sensors. In the end to get the fourth I had to remove the Y pipe and use a torch and a 24" pipe wrench. Of course I broke 3 studs on the exhaust downpipes, tried welding a nut on the remaining pieces of studs, then gave up and drilled them and installed helicoils with new studs. So it took half an hour to replace the first three O² sensors, then four hours for the last one. Darn those harsh winters and darn that salt they put on the roads.

 

This is the socket that I used to replace the upstream sensors. http://www.zoro.com/g/00044724/k-G1301352

Was your wrench a 6pt wrench?

I would suggest soaking it in pbblaster (apply a few times per day for a few days), try to remove it. If not successful, apply heat. As a last resort you can cut off the body of the sensor and use a socket.

 

If it's rounded off you'll probably have to clamp vise grips on it as tight as you can get and hit the vise grips with a 2lb hammer. turn the vise grips so the side you will be hitting is the side with the adjustment screw. Use an old set, they may not be good for much when you finish.

 

agree on vice grips.

Or hack saw off the top of the sensor.
Put a real socket down onto it

out it comes.

Use Wd-40 or PB-Blaster.

 

I soaked mine for about a week with PBBlaster, every day after i got home when the truck was still warm.
I used a six point crows foot off Amazon .
I was surprised how easily they came out for 14-year old O2 sensors, I dont know how much good heat will be to you as the your 02 have already been heated thousands of times.

 

I used that offset socket on mine and worked perfect but, I think he said his is rounded off? So he may have to break out the old vise grips.