Walkthrough: Replacing the front O2 (Air Fuel Ratio) sensor

[gazmanster]

I thought I'd share my experience replacing the front O2 sensor on my MY05 Liberty GT - so if you want to tackle this job have a read below...

Overall I it took me about 40 minutes and I was being extra careful and I am no mechanic.

First the tools you will need:



Then the parts:



I used the Loctite Freeze and Release as I was paranoid that the sensor would be stuck firm - it worked a treat

The sensor is shown below - it is near the firewall on the drivers side below the intercooler - there is no room to get in there to remove it without taking off the intercooler.



Firstly remove the engine cover - four screw clips and you're done:



I also removed the -ve battery lead while I worked to help "reset" the ECU (not sure if this really does reset the ECU but my radio stations needed a re-tune anyway ).



Remove the two bolts on this pipe (not sure what this is called ) - This pipe is sealed with a rubber like seal - so don't worry - there is no gasket to break.



While you are on this side of the intercooler may as well remove the mounting bolt and unclip the flexible hose:



Now move to the other side of the intercooler and remove the mounting bolt, I also removed the entire mounting bracket (don't know if you need to but it is only two bolts):





Undo the hose clamp and disconnect the flexible hose from the blow off valve:



Then remove the small flexible hose:



Now undo the hose clamp:




The intercooler is now free! - you can wiggle it off gently - it came off pretty easy for me.

Now you have a clear view of the sensor:



Dont forget to unclip the sensor.

I liberally sprayed the end of the sensor closest to the thread with the Freeze and Release for about 10 seconds and left it for about 5 minutes.

I used my trusty shifter to undo the sensor (I think it was around 22mm but my spanners only go up to 19mm) - it was firm but not stuck.

Here is the old sensor:



And the new one out of the box:



The cover over the thread hides some thread anti-freeze stuff that looks like zinc paste to help prevent the thread from sticking in the future.

Now all you need to do is put the sensor back in and put everything back together - done.

I was stoked when I started her up and the Engine Light was gone (and has not returned since)!

Notes to self::
Dont drop bolts onto the top of engine unless you have a magnet on a stick
When the exhaust gets hot the stuff you sprayed to release the sensor will burn off and stink causing some smoke - don't freak out

Hope this helps.

Administrator - can you please move this post to the walkthrough section?

[tangcla]

Dont drop bolts onto the top of engine unless you have a magnet on a stick

You really need to buy the magnetic tool. It's a godsend.

Nice walkthrough, too. I hope i never have to do it cos the last two times I had to replace the O2 sensor, it has been under parts warranty

[ultrablue]

thanks for that ,your pics are not working for me

[gtspec]

thanks for that ,your pics are not working for me

+1

[gazmanster]

Updated image links - hopefully working for everyone now

[3rspecb]

nice gloves

[smythie]

I have found using an 8mm socket is a lot easier than a blade screw-driver for loosening or tightening hose clamps :winnk:

When tightening the clamp you do need to pay attention to not overtightening due to the much greater leverage you have