O2 sensor size

Hey all, I removed 3 of my 02 sensors really rather easily, but I'm buggered on the front passenger side (is that bank 1 number 1?).

What size are the heads on these bloody things, I have been trying with a 22m spanner and It just keeps slipping and rounding it. The others I removed with an adjustable, it really doesn't look like the 22mm fits but it maybe just rounded like mad from a previous owner.

Cheers all

If you just changing it don't worry about it, cut the wire so you can get a six sided ring or socket over it, you may have to murder the metal work above it to do this.
But before doing any of this, soak it in freeing off fluid and tap it all round with a reasonable size hammer. Give it bit of heat if really necessary but also try turning it a wee fraction clockwise to break the rust seal.
I had exactly the same problem with the only one on Wifey's Pluriel. This method worked.

Yeah thanks stanley, I have allready done that with the ring spanner, and it still slips . Other thank just keep hammering away with the ring spanner I don't know what else to do know.

I'm going to try and get a blow torch on it next I guess and just hope the spanner holds out. Is it definitely a 22mm then?. I will try and give it some tapes with a hammer as well, it's allready been covered in penetrating fluid.

rojohex said:

Yeah thanks stanley, I have allready done that with the ring spanner, and it still slips . Other thank just keep hammering away with the ring spanner I don't know what else to do know.

I'm going to try and get a blow torch on it next I guess and just hope the spanner holds out. Is it definitely a 22mm then?. I will try and give it some tapes with a hammer as well, it's allready been covered in penetrating fluid.

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Not having a modern V8 I have no idea, but rust etc will often reduce the nominal size of an old nut. You could try hammering a 6 sided 21 over it, or the in between sized imperial, whichever size that would be. Or else, you are down to heavy duty adjustables, stilsons, huge Mole wrench whatever.
But loads of soaking, combined with heat then cold water. You dont want to snap it off and get yourself into having to drill it out. Just try to tweak it a bit from side to side. Once it starts to move, you'll be OK. But they are notoriously bastards to get out. They may even be supposed to be only taken out when hot, i.e. the engine has been running a while. I'm obviously no expert on that. Maybe someone else will come on who knows more exactly.
Best of luck.

If you are in any doubt over the spanner size, measure across the flats on one of the ones you have taken out with a caliper or micrometer.
Yep it's 22mm. Must be a real sod of a job as you can get spedial tool to get em out.
Amazon product

Yeah I tried measuring on the old ones and they don't seem to like the 22 very much either.

Tried the tools but there isn't enough clearance, it's a real pig, same issues with big grips, adjustables etc.

I did think about the next size down in imperial, even cutting a 21 ring on a spanner and trying to force that.

Going to try driving it for a bit then trying again.
Last thing I want is to take the manifold pipes off as you know I will snap a stud.

I guess I was lucky removing all 4 of my O2 sensors.
Ordered an O2 wrench kit on eBay with all the attachments.
Soaked the areas of the O2 sensors a week prior with PB Blaster.
The tool kit took awhile to get mailed off from the distributor so I said “F” it and used an adjustable spanner to remove the O2 sensors and VOILÀ! All 4 sensors were removed easily like butter was on the threads.

rojohex said:

Yeah I tried measuring on the old ones and they don't seem to like the 22 very much either.

Tried the tools but there isn't enough clearance, it's a real pig, same issues with big grips, adjustables etc.

I did think about the next size down in imperial, even cutting a 21 ring on a spanner and trying to force that.

Going to try driving it for a bit then trying again.
Last thing I want is to take the manifold pipes off as you know I will snap a stud.

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Best of luck mate.

JUKE179r said:

I guess I was lucky removing all 4 of my O2 sensors.
Ordered an O2 wrench kit on eBay with all the attachments.
Soaked the areas of the O2 sensors a week prior with PB Blaster.
The tool kit took awhile to get mailed off from the distributor so I said “F” it and used an adjustable spanner to remove the O2 sensors and VOILÀ! All 4 sensors were removed easily like butter was on the threads.

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So why do you think yours were so easy? the PB? the time given to them for it to soak in? Or maybe the previous owner hadn't done em up too tight?

rojohex said:

Yeah I tried measuring on the old ones and they don't seem to like the 22 very much either.

Tried the tools but there isn't enough clearance, it's a real pig, same issues with big grips, adjustables etc.

I did think about the next size down in imperial, even cutting a 21 ring on a spanner and trying to force that.

Going to try driving it for a bit then trying again.
Last thing I want is to take the manifold pipes off as you know I will snap a stud.

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That must be the reason why the special tool has such a short handle. I have to assume either you belt it with a F off hammer or stick a breaker bar in the square hole. Or both!!

Honestly, it could be all 3. Me using PB to soak in and the PO having a very limp wrist. Lol

JUKE179r said:

Honestly, it could be all 3. Me using PB to soak in and the PO having a very limp wrist. Lol

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You don't need a particularly non-limp wrist to hit a spanner with a hammer! I think previous owners have rounded the hex corners off and he needs a special 6 sided ring/socket, preferably one that exerts pressure on the flats rather than the corners.
He could do worse than saw it down to the hex or just above and then attack it with a 6 sided socket and a short bar, hitting it with a lump hammer, gently but firmly.
After liberal doses of PB of course.
But heat will prolly be quicker.

I take it you have done this sort of search?
https://www.google.com/search?q=tec...i22i29i30.14296j0j15&sourceid=chrome&ie=UTF-8
The tip about using an air hammer seems good but impractical unless you have one to hand!

Cheers all, yeah I have looked at it. Access is the main issue here, that and what I guess is a rounded head.

That's why I assumed the size must be off as the spanner really doesn't want to fit it, I get a few swings of a hammer and the spanner then moves of the head.

Will blast it with heat/try it when hot after a drive, and soak it all again in penetrating fluid.

Cheers guys

rojohex said:

Cheers all, yeah I have looked at it. Access is the main issue here, that and what I guess is a rounded head.

That's why I assumed the size must be off as the spanner really doesn't want to fit it, I get a few swings of a hammer and the spanner then moves of the head.

Will blast it with heat/try it when hot after a drive, and soak it all again in penetrating fluid.

Cheers guys

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Do you have access to welding equipt?
If so, weld something you can hit, to the hex, mebbe an old spanner, then hit the feck out of that.
If all else fails, cut out of the exhaust the section where the sensor is then buy a new threaded bit make a new plate with it in and weld it in place of what you took out.
One of the guys on one of the YouTubes mentioned sometimes having to do this. Especially if you cannot drill it out.

All done!!!, I had the engine running in the end and I shifted the thing!. And it was quite rounded when it came out.

Next question is does the ECU need a reset post 4 new sensors?

Thanks guys, nothing more frustrating is there

rojohex said:

All done!!!, I had the engine running in the end and I shifted the thing!. And it was quite rounded when it came out.

Next question is does the ECU need a reset post 4 new sensors?

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Shouldn't do, provided you disconnect the batt and stuff before you reconnect the new ones. The ECU should just check to see if they are there, but this is me talking and I know ten tenths of feck all when it comes to electronix. However this is the way the sensors for ABS work.
IF the fecking things need recalibrating or summat this may be wrong.
BUT when I did the one on Wifey's car, all we had to do was reconnect the batt and once switched on, give it time to sort itself out before starting it.
Others will come on and correct this if I am wrong.

rojohex said:

All done!!!, I had the engine running in the end and I shifted the thing!. And it was quite rounded when it came out.

Next question is does the ECU need a reset post 4 new sensors?

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So pleased you got it out!!!

Thanks dude, I was worried for sure!. I was being cheeky and didn't disconnect the battery, so I guess I will leave it off over night and try again tomorrow with a good test run.