hey
i was trying to install a test pipe, but i couldn't get the sensor off the cat. it's really tight and i tried using liquid wrench.

thanks

 

A good penetrating lubricant and let it soak over night. Is you can't remove it with a wrench you might have to get an O2 socket to remove it. Some sensors can't be removed as they're too far rusted.

 

Make sure the wrench you use is the exact size for the sensor. I had to whack mine with a hammer to break it loose. After that, it unscrews in your hand. You will also notice that as you unscrew it, the wire gets all twisted up. Try to turn the cat instead and when putting on the test pipe, turn it onto the sensor before putting the pipe on the car. This will make for less twisting.

 

crap. i used those adjustable wrench on the O2 sensor.

this mod is harder than i first expected.

 

i used a cresant wrench for it
no problems at all

 

This is true, but the crescent wrench should be large enough that the "pinchers" completely cover the 2 opposing flat surfaces of the sensor. If you use a crescent wrench that is too small, it will tend to slip and round off the corners of the sensor.