Went to drop my stock exhaust which is in great shape. Went through a couple turns of the sensor and now it feels like it is locking up. Is this normal? Possibly soot buildup on the threads?

or..... do you think the threads have crossed?

 

Spray the threads with PB Blaster, screw it back in, then slowly back it out. Repeat as needed.

 

Well, I just dropped the exhaust (disconnected the sensor at the 3-prong plug).

I didn't try since its been dropped but it won't thread back in very far. I may need some muscle put into it now that its off the car. I did initially spray with PB blaster and might try some more and let it sit.

I just hope the threads haven't crossed.

 

Following up with this, I found that the threads on the o2 sensor itself were pretty messed up. I am fairly suprised. I am not sure if this is a common thing or not. Based on what I was feeling, I kinda knew the threads were screwed up.

I was able to get it out by tightening and loosening gradually. I was able to repair most of the threading by reinstalling and tightening/loosening very slowly.

Given that the exhaust is in good condition the sensor originally broke really easy. It was while unthreading it, that it locked up on me. I don't feel like I did anything to induce the cross threading.

My luck...

 

its not uncommon for this to happen. typically it happens on the o2 housing though.

www.oxygensensors.com sells for a great price and usually free shipping. its all OEM like products, not the universal splice required stuff.

when you reinstall, remember to use antiseize compounds on the threads.