O2 sensor is stripped. What size tap do I need?

[bjlinma]

I tried to change the O2 sensor in my '89 XJ with 4.0L. The old one came out stripped.

Does anyone know what size tap I need to try rethreading the openning? I think it's worth a try. The new O2 sensor almost looks like a spark plug thread. I know they sell tols to rethread spark plug holes.

The only other alternative I can think of is to head to the bone yard and get another exhaust manafold. I don't know if I'd trust taking off the old one and doing a HELI coil. (sp?)

I don't have the cash to get into a header and new exaust system right now.
thanks

 

[8Mud]

You can buy the threaded bung seperate from the exhaust manifold, a fairly good muffler guy, could weld the new bung , on for you, with the manifold still in the Jeep. It would be difficult, but not impossible.
I´d check out the exhaust manifold closely, it may have to come off of there anyway, most are cracked Some worse than others.
Search, O2 sensor bung, at www.summitracing. com

 

[shloky]

You can get the bung for 5.50 shipped on ebay.

 

[bjlinma]

From what I could find out surfing, all O2 sensors are 18mm. O2 sensors started out using a modified spark plug fitting and it has stuck. I'm going to try an 18mm spark plug chase tool from the local auto parts store. $4.99

I will post the results here.

 

[ghettocruiser]

Autozone sells a spark plug thread chaser tool. It has two ends. The one end will work perfect for the O2 sensor. I had to do the same thing in my firebird. If it is stripped really badly it might not help, but if it does you just saved yourself a lot of money. Make sure you use some sort of oil while you are chasing the treads though! I used WD40 which worked fine. Good luck! Atleast our O2 sensors are in a fairly easy location to mess with.

Justin

 

[bjlinma]

Thread chaser worked great. It is a double sided one. 14mm and 18mm.

Sensor is in and working great. Mileage went from 13.5 to 16.2 with this one change. I'm now a believer in all the other posts about O2 replacement helping mileage.

 

[8Mud]

Nice to know, thanks for posting the solution. A light coat of copper grease, has sure has helped in removing my O2 sensors the next time. I´m pretty carefull, about keeping the grease away from the sensor end.
A dab of high temp. anti sieze, would probably be better than, the copper grease, but the grease is cheap and does the job.

 

[bjlinma]

The sensor came with anti-sieze on it. It was a Bosch and ran me about $45 at the local auto parts.

 

[comanche91]

Well, this post saved my bacon tonight. My O2 sensor came out of my S/S headers stripped and I had visions of removing the header (beetch) and re-welding another bung. Went down to AutismZone, picked up an 18mm spark plug thread chaser, and it worked like a champ. New sensor went in cleanly and tight. Thanks for this post guys.