carguy07

Autozone and Harbor Freight have them too.

salimshah

Tip

My mechanic teacher taught me that when ever you take out hard to to turn bolts/nuts/sensors always unthread 1/2 a turn and thread back 1/4 turn.

Salim
count-down 10, 9, 8, 7, 6, 5, 4, 3, 2, 1

weinkaufjr

Roger that and a drop of penetrating oil before the 1/4 back in helps too.

wvuguy

Well I picked up thread chaser locally, cleaned the threads on the exhaust, tried to put the new sensor on and ended up with the new sensor threads looking like the old one It went in nicely in the start and then got harder to turn. Couple more turns later it got loose and came out. Now the sensor is barely hanging on to the exhaust. I am guessing I need to order 18mm x 1.5 die to clean out the threads on the sensor.

salimshah

It seems the threads inside the exhaust are shot and even the sensor threads are compromised. I think the die and tap are needed but if the material is lost, you can't recreate it.

Helicoils come to mind. Being exhaust, I dont think JB Weld would work. You can have a nut welded in. One can think of more complex adapters but then the sensor tip would not be in the exhaust stream.

Let us know how you solve the problems.


Salim

wvuguy

Thread chaser threads in nicely into the exhaust so I am not sure if the threads in the exhaust are completely shot. I am thinking I did not clean the threads properly before putting the sensor the sensor in which messed up the sensor threads. I will try to screw in a 18mm spark plug or bolt into the exhaust to see it threads in. If thats the case I will try get the sensor threads fixed. I saw heliciols at advance auto parts. I might try that or just have the sensor welded. Thanks.

bearbrew

You can weld a new bung to the manifold but you will most likely destroy the sensor if you try to weld it in position. The heat of welding may overheat the internals.

salimshah

If the thread chaser seats right and secures well, (threads are good) then why would the sensor not fit properly => Conclusion I can draw is that the thread do not match. I would try to get a nut and bolt and check the exhaust threads with the bolt and then see what is going on with sensor threads with the nut. The thread chaser may have cut new threads with a different pitch. Come to think of it you can externally mate the sensor with the chaser to see if the pitch matches. Only then invest in the die.

The more I think about the problem, more I am convinced it is a pitch issue. Although any one can cross thread nut/bolt/sensor.

Salim

code58

This is 1 of the reasons I don't like thread chasers. The professional ones that I have (Mac) are way to soft and don't do the job at all that a tap does. You don't want to run a tap too deep and make your fit to loose, but a tap is very hard and if lubed and operated properly, should definitely clean the threads so that there was NO CHANCE of damaging the sensor threads. I fear that he may have lost that sensor for good.

Edit: Don't they normally use a pipe thread on something like spark plugs and sensors (and a lot of other things too) rather than bolt thread. Maybe he used a U.S rather than Metric thread.

wvuguy

I did use the metric thread chaser size 18mm x 1.5. I think what I did wrong was I did not clean the threads all the way before trying to put the sensor in and ended up with messed up threads on the sensor. The sensor does have good 3 threads towards the end. The front ones are messed up. I think as long as I can straighen up the initial threads on the sensor and latch them on the exhaust threads I should be ok. Also the threads on the exhause feel fine if I touch with the finger. Plus as I mentioned the thread chaser goes in and secures pretty easily. I will give straighening up the sensor threads one chance and see how it goes.

weinkaufjr

You may have ruined the threads on your new sensor, but on balance that is better than ruining the threads on the manifold. I have seen the threads on the sensor be junk but the manifold threads salvageable. Use a pick and magnet to get as much junk out of the manifold threads as possible. Put a little grease in the thread chaser grooves, screw it in until you start getting resistance, back it out and clean as best as you can. Repeat as necessary until the chaser goes in the whole way easily. I understand the arguments in favor of a tap but you run the risk of cutting more material off the manifold that you cannot afford. If half the threads on the sensor are gone, I would get a new one.

wvuguy

I was able to fix the sensor threads using 18mm x 1.5 die I ordered from amazon.com http://www.amazon.com/18mm-1-5-Carbo.../dp/B0007CNJ2C.

I cleaned the exhaust threads once again with the thread chaser, fixed the oxygen sensor using the die and put it back in. It seemed to go in fairly easily and got in there all the way fairly tight. My exhaust was starting to smell like rotton eggs after running on old bad sensor barely dangling in there. Thanks every one for the help.