O2 Sensor torque

D

depletion

Daily Driver
Hello,
I am replacing the two oxygen sensors (on a non-Fiat) this weekend. Rather than purchasing factory manuals for $90 or so, I thought I'd post here since you seem very polite about somewhat off-topic posts.
What should I torque the sensor to? Since it is not a moving part I am guessing that it should not be very many ft-lb (Nt.m). Thanks for the help.
I've owned 2 fiat's and 2 ferraris and hope to get an X in the future.

Regards,
Tim
 
I will give you a guess.

As I do this by feel consider this. The new O2 sensor has a ring crush washer seal. Remove the old sensor, install the new sensor and tighten until you feel moderate resistance. I will guess 25 Foot pounds or so. The crush washer has to compress, if it does not, then the sensor will leak in short order and possibly fall out of it's bung. The crush washer also acts like a lock washer.

TonyK.

Grimsby Ontario Canada.
 
I'm not familiar with the crush washers...

All others I have replaced have had a PIPE thread fitting that seals like most plumbing... and I know NOT the specs.

I usually just tighten them very snug as I depend on the threads to seal.

I also understand that most manuals say to use a HIZGH TEMP ANTI-SIEZE on the threads so they can be more easily removed in the future.

Hope his helps...
 
The X1/9 service manual says 30 - 36 ft lb for the O2 sensor. The manual for my Civic says 33 ft lb. I see a pattern here...
 
Went through this last year changing O2 sensors on a couple cars in the fleet... 25 to 35 ft-lb... but I don't think its that critical. However, do not forget the anti-seize... (typically supplied with the new sensor)
 
Uh uh...

Tony, all the O2 sensors for our Fiats are the type that use a crush washer. If you depend on the threads to seal you will eventually be disappointed. Perhaps you are getting O2 sensors that have had their crush washers removed?

If you're feeling thread resistance, you need to get an O2 sensor thread chaser and clean the threads. Available at most FLAPS.

To all, be sure to remove the old crush washer with the old sensor when changing. New sensors (Bosch at least) include an application of anti-seize already applied. They do this to avoid problems of inept folks applying anti-seize where it can damage the sensor.

Hope this helps!
 
Perhaps... But I have never worked on...

... this particular part on a FIAT... only Hyundais, Hondas, and Mitzubishi's.

If there was a crush washer going in or coming out of any of these, I certainly don't remember them. I believe we used Bosch replacements. Anyway, something to remember to watch for from now on.
 
Jim... see Greg's statement above...

Do you remember "crush washers" on any or all the other models you worked on?

I'm not trying to gang up on Greg, but am indeed wondering where MY memory is going in my old age!
 
I do remember one having a "crush washer"... like a spark plug. However, I just don't remember on the other one.

And to be honest... although I did look up the torque specs at the time... I did not use a torque wrench to put them in. Access did not allow for it. I used my best guess... feels right... arm calibration.
 
HA... so my MIND is still in limbo!

Thanks a lot...

Maybe yours is starting to go also! I'm in GOOD company I guess!

HAHAHA!
 
Thanks to all for the help

I got the O2 sensors in this weekend, also a set of plugs, and the car runs nicely now.
Upon some fine day in the future I will get a X1/9 because:
a) it's midengined
b) the parts are cheap
c) I test drove one and was very favorably impressed
d) it's Italian and cool
I had a 124 spider for a while but should have got an X as, my impression is, the chassis is much stiffer. It feels safer, too, with the targa top rather than full open top. You guys and ladies run a great forum - keep on doing it.
 
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