I don't know what to think. it appears that the person who swapped out the exhaust manifold for headers really screwed up the o2 sensor. it appears do be welded into my exhaust headers... but I could be wrong.

obviously, when headers are fabricated for this car, the o2 sensor needs a hole to screw into. These things screw in, right? I've looked at loads of pictures of them and they appear to have a hex head and threads, so it makes sense that they would just screw right out. Who would have the knowledge to build freaking headers and then do something as stupid as welding it on?



I've soaked it in WD-40 and wrenched on it but nothing. what do you guys think? I just want to make sure that it definitely screws out.

 

Cut it off, grind up the area to make it smooth, weld in new oxygen sensor bung and installed new oxygen sensor.

 

bung, eh?

will a big nut work? (hehe) i suppose it has to be air-tight.

 

what hoov100 said. its the best way.

 

I can't seem to find a specific o2 sensor bung for this car. Can it be researched according to the correct sensor?

 

^^^ First Google result:

Discount Nissan 280ZX Oxygen Sensor Autopartsdeal.com

O2 Oxygen Sensor Nut Bung 02 M18 x 1.5 THREAD | eBay

I've welded in several of those bungs... works like a champ!

 

perfect nismopick! exactly what I was looking for!

 

that actually is screwed into the o2 bung in your picture. get a 18mm box end and try or a pipe wrench, betcha it comes out, that said its probably just as quick to install a new one.

 

If you're replacing it anyway, I just cut the wire off of mine so I could fit a socket around it easily. Also get some PB Blaster (or WD 40 if nothing else) and spray it a couple times a day and then try.