02 Sensor "Welded"

[WyattH]

I know i know. I make alot of random problem threads. But its the only time i really come here.

My passenger side precat 02 sensor is IMPOSSIBLE to get off. I have sprayed copious amounts of liquid wrench penetrating oil on it. And then i was pushing so hard against it that i was about to pick up that side of the truck!

I cant think of any way to get this thing off. Any help?

 

[SoNic67]

I am in the same boat. None of my pre-cat sensors are comming off. O2 socket, with penetrating oil, with freeze spray, 24" breaker bar... Tried with the exhaust cold, warm, almost hot.
I was planning to replace them preventive and maybe an increase the gas milage.

 

[WyattH]

As was i. Its the only code my engine is throwing and im getting about 15 mpg right now on the 4.0 sohc. Its killing my mileage and the only problem im having is getting that thing off.

 

[drbenz]

I don't know if this wil work on a o2 sensor but look at post #8:
http://www.explorerforum.com/forums/showthread.php?t=349007

 

[jremington59]

You may have to heat it up with a torch.

 

[windsors03cobra]

Stuck fasteners always come apart decently when they are turned cherry red.

 

[firepop5]

I agree with the torch. Use mapp gas instead of propane, it gets hotter. Acetylene is even better, but not a DIY type of thing.
Heat the area around the base of the sensor (not the sensor itself). You want the area around the sensor to expand. Cherry red is good. I used a pipe wrench with a handle extension for added leverage. (Don't know if you have the room to do so). Sometimes you can break it loose by tightening it first. The wax might help too.

For safety, keep a fire extinguisher nearby.

 

[RomeovilleIL]

I agree that heat can be your friend in the case, but might simply be a tool issue. In the past I had very poor results using the tall silver socket with a split in the side. It's tight space to begin with and when you apply force the torque isn't straight line so the sensors often don't budge.

Instead we unplugged the sensor and slid a 7/8" hex-end wrench down the wire snug on the bolt then tapped the handle with a hammer while trying to turn off. You have to hold the wrench tight to the sensor & don't hit too hard or it may round it off. Not a great solution, but usually worked.

For the past few years I have used an O2 "wrench adapter". The link shows one on ebay but you can pick one up at most any of the parts stores for under $20. The one I got is more of a figure 8 than a tear drop shape, but the concept if the same. They do a much better job of keeping the leverage straight and right on the base of the sensor with less risk of stripping or rounding off. Plus you arent trying to get a wrench over the plug and down the wires. While keeping torque on it I tap the end of the socket wrench with a hammer (there usually isn't enough space to get a breaker bar on straight). So far has worked on the cars I've encountered without having to resort to a torch. As noted its tight space and getting burned trying to reach around those pipes is not fun.

http://www.ebay.com/itm/AMPRO-T7551..._Automotive_Tools&vxp=mtr&hash=item4844639adc

 

[SoNic67]

Heat the area around the base of the sensor (not the sensor itself). You want the area around the sensor to expand. Cherry red is good.

If the area AROUND sensor EXPANDS, the hole will SHRINK and it will COMPRESS even more the sensor.
Sometimes it works just because the red-soft metal will deform plastic and allow movement - of course with damaging the original threads.

 

[Yadkin]

The hole will grow when you heat the metal around it. Use MAPP gas. Then get your wrench on the sensor and hit it with a small spray of water to shrink it just before you yank it loose.

 

[my98nnj]

Heat is your best friend, red hot, it will twist out like butter. Every mechanic knows that secret.