I've been dealing with a CEL due to a bad O2 sensor for a couple years. So, I've been treating the thing with penetrating oil for the past few days and finally put a wrench on it last night.

Well, it just crumbled. The threaded parts stayed in place, the rest practically fell off. So, I can't pound/drill it out as it's facing upward.

Do I drop the exhaust for fear of cracking the downpipe? Or, do I just order a bung and weld it in on the side of the pipe that I can easily access?

I'm going to try the latter with . I hope it's the right size. If not, I'll try other sizes. For $7, it's not a painful experiment.

Anyone know the thread size of our O2 sensors?

 

I believe the thread is 14mm. Not sure of the pitch.

 

I would check that, I tried to put spark plug extenders for the lower O2 sensors in last week and thought they were 14mm and it turns out mine are 12mm..........

 

If the bung I ordered isn't the right size, I guess I take a good 02 sensor to the hardware store to match up thread, and buy a nut (maybe stainless) of the same size and weld it on.

 

Well, the bung was way too big. I figured as much when I looked at a Ford 5.0 in the corner of the garage and saw the size of that O2 sensor.

Looks like a trip to the hardware store for a bolt.

 

I tried to do my car this weekend and found the threads to be 12mm. I have been unable to find an extender with the 12mm threads. Has anyone had any luck with this? Where did you get the extenders/spacers?

 

I have been unable to find any 12mm extenders and am considering using one or two 12mm bolts welded together to get the spacing.

 

A 12x1.25 bolt is the winner. I stopped with an O2 sensor at the hardware store and coughed up $.90 for it. At nearly a 1/2 thick, there's plenty to weld to. I don't think you'll need 2.

 

I too am replacing all 4 O2 sensors and the backs snapped off. I just tried the new bung route on my XJ6 and ended up having to buy a new downpipe. Even with the heat turned way down on the welder I burned through the exhaust tubing. The walls were nearly paper thin.

 

May or may not be aware of the connector ready Bosch # 13789 equivalent to the Denso and it would save you some big money . Spark plug Autolite #4163 has the correct 12 mm crush washers if they are missing . Anti - seize is not a bad idea for in service removal , careful not to get too much on and contaminating the sensor . Proper connector hookup to the correct connector is important and may be a source of problems although I have not experienced it myself . On the AJ16 engine the #1 cylinder is the forward most position ( opposite of the AJ6 ? ) . So the B1S1 ( bank 1 sensor 1 ) is on that pipe forward of the forward Cat . B1S2 is aft . On the ECU side of the connectors they have the same wire colors with exception of the one important return signal wire to the ECU . B1S1 Green , B2S1 Brown , B1S2 Blue , B2S2 Red . Not to be confused with the term orientation as this is a requirement to have the Jaguar shop " match " the changed sensors with the ECU under certain ( unknown to me ) conditions . Some readers may already know this but this information is for others that are new to this . Hope this helps some people . The old original sensors can be cleaned or refresh to possibly give you more service life by soaking overnight in some gasoline ( small baby food jar ) periodically tapping out softly against your hand and re-soaking a couple of times . Don't get the wires wet . Seafoam product seamed like a good idea ( their label says it is safe ) but I was able to get so much deposits out there may not have been anything left to clean . The sensors can be bench tested with a propane ( not high temp welding ) torch to get them to operating temp and deprive them of the O2 which then can be read with a digital multimeter . But then again they could be " out of range " . Look for some corrosion of the B1S2 and B2S2 connectors behind the back of the valve cover .

Bosch Oxygen Sensor 13789 - Read Reviews on Bosch #13789

Thanks , Parker