O2 sensor removal
 

I'm getting ready to remove the O2 sensor for my 1981 SC. Is it "easier" to remove when the exhaust is hot or cold?? I always plan for the worst.

I removed it cold. I used the following method:

First, I cut the wire to put a box wrench around it (long handle, good clearance from other stuff).

Then:
1. try to budge with box wrench.
1. spray with lots of WD-40, all around.
2. Tap on it with wrench to vibrate the WD-40 into the threads (theoretically).
3. Wait for about an hour.
4. Repeat as needed.

After about 4 hours, it broke free. You might have better luck just spraying it good in the evening and trying to remove it in the morning. I happened to have a day where I could work on it over the course of the day.

It's really quite easy, one the rust is broken up.

O2 sensor ......
 

When I remove the O2 sensor on my SC it took the threads with it. Go ahead and buy yourself a sparkplug rethreading tool with both 14 and 18mm threads (double ended w/hex in middle). The oxygen sensor uses the same threads as a sparkplug so even if the old sensor comes out "ok", you can still clean the threads before installing the new one.

Fred Cook
'80 911SC coupe

Though WD40 can help in situations like this, the best thing I've ever seen when it comes to loosening rusted parts is PB Blaster. You can probably buy it at your local auto parts store. Spray it on the night before, let it sit, and you should be good to go the next day. Hopefully it'll help you leave the threads behind!! :D

You'll need a special socket to get the sensor out. I bought a cheapie at the local Autozone, and cut a slice out of the side using my rotary tool.

This isn't a difficult job. Take your time. Good luck!

I'll second the PB Blaster. I started spraying the bung two days before the eventual removal. Use jack stands! Get a wrench with a long handle.

Thanks everyone for your great feedback.
Mike

My all time favorite is Kroil. If Kroil can't get it loose, it aint coming loose.
BTW I tried some liquid wrench super penetrant last week (I ran out of kroil and it was all they had), waste of my time and money. IMO not much better than WD-40.

I replaced mine last week. I did it with a cold engine, and it came out with very little effort (not much more than a firm tug on the wrench).

For the new O2 sensor, it was supplied with a bronze-ish anti-seize compound that I used on the threads.

So you guys think it is an easy job. I worked on it for a few hours and finally just pulled off the Cat and replaced it with a "test pipe." I have been testing that pipe every day for years!