I need to replace both rear sensors and I thought I'd be able to get them out by just crawling underneath the truck with a spanner and some brute force. No dice.

I have a 7/8th O2 socket, but there isn't enough clearance to use it. (The sensors are 22mm). I'm guessing I will have to jack it up, perhaps even use a torch to heat them up. Any tips would be appreciated. Is a flare wrench needed?

 

Try a little bit of PB blaster

 

I use a 12" crescent wrench every time. PB blaster helps. I actually prefer transmission fluid mixed 50/50 with seafoam. Seems to work better. There's also Seafoam Green Stuff (I think that's what it's called; something like that) which I've heard works miracles, but haven't found anything I couldn't break with the AFT/Seafoam yet.

 

I use a 7/8 open end wrench and I get em everytime.

 

Oxygen Sensor Replacement For Discovery 2
The right tool makes a difference

 

I tried a wrench, wouldn't budge. Rounded a little. Went and bought the socket. No Dice, rounded it right off. Drilled a pocket hole, used an Allen wrench as a pivot with the special socket, damn near broke the socket.

Cut the wires, for access, nothing.

Didn,t want to risk heat under the car by myself. Took it to a local reputable aftermarket muffler garage, they heated/ cooled, heated cooled, etc could not get it out.

Fitter said screw it and just cut the pipe and welded in a new piece with fitting. 120.00 CDN, but the owner said it would have been 40.00 if I had left it as it was in the beginning. 30 minutes work.

For 40.00 CDN in hindsight would have been a steal considering the socket was 15.00 lol.

As a tip though, he said, heat the pipe then cool with water, try it with the right tool, heat again and try it as it cools. Usually comes out then he said.

This is 2003 Salty road climate here in Toronto, 93,000 miles presumably original.

If you have the equipment at hand it would seem doable. My absolutely would not budge. Even after heat.

I'll not bother next time and go to a shop. They let me use my own O2 Sensor so no mark up from them.

 

I used the O2 sensor socket but I live where they don't have to salt roads. I cringe at reading about some of the problems you guys face up North.

 

Heat, you'll have to break out the touch and they will pop right out with ease.