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

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

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

You can get the bung for 5.50 shipped on ebay.

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.

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

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.

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.

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

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.