How to remove rear downstream O2 sensor?

[autoteleology]

I am trying to diagnose a P0420 code and I am in the process of replacing my O2 sensors. I have replaced the upstream sensors (from a prior fix) and the bank 2 downstream sensor, but the bank 1 downstream sensor is stuck in the catalytic converter hard. I wrenched on it with a (crappy) flex head ratchet for a good hour or so last night with Gibbs penetrating oil before giving up and putting my car back down so I could drive to work for the night shift.

Does anyone have any suggestions for a good tool / process for getting it out that hopefully will cost less than just having a shop deal with it? It's in such an obnoxious position that it's hard to get any direct mechanical leverage on it.

 

[Texas Marauder]

Heat. A propane torch would probably do it. Don't burn the car down.

A new cat is probably the only solution to a P0420 code.

 

[autoteleology]

Heat. A propane torch would probably do it. Don't burn the car down.

A new cat is probably the only solution to a P0420 code.

It's more likely than not I need a new cat (given my prior PCM/injector issues) but if I do, I need to replace the O2 sensors anyway, so I might as well do it first and see if it helps before spending a lot of money.

If I do replace the cat(s?), are there options on the market I should go for over something stock equivalent? I know there's been a crackdown lately on tuning in terms of environmental regulation, downpipes used to be one of the most common upgrades from my reading but is it even worthwhile to try to get more performance that route any more?

 

[BradM]

Heat the bung, not the sensor, and then wrench while it's hot. Otherwise heat everything and let it cool before wrenching.

 

[kryptto]

If I do replace the cat(s?), are there options on the market I should go for over something stock equivalent?

Stainless Works, Magnaflow or PPE

Ford Taurus SHO / FLEX Ecoboost V6 2.5″ Downpipes 2010–2019 – PPE Engineering LLC

ppeengineering.com

2014 Ford Taurus Catalytic Converters | MagnaFlow

Need a 2014 Ford Taurus Catalytic Converter replacement? Shop all MagnaFlow 2014 Ford Taurus Catalytic Converters to find the best price and quality for your 2014 Taurus needs.

www.magnaflow.com

2010-21 Taurus SHO Downpipe

stainlessworks.net

 

[SHOrod]

Are you using the spark plug style O2 socket or the offset oil pressure switch style crowfoot O2 sensor socket? You might have better luck with the crowfoot style and an extension to get the wrench below the exhaust where you can get a bit more leverage on it.

-Rod

 

[SHOtimeJoe]

Just cut plug off and use box end of wrench. If you are replacing old one.

 

[autoteleology]

I realized that an extension bar will probably work given I have offset O2 sockets. If that doesn't work, I'll get a proper breaker bar, and if it's still stuck, a propane torch to heat the bung.

I'm not very mechanically inclined, but I am trying to teach myself to be, and this forum has been very helpful in doing that. Thanks for the help, everyone, I'll let you know when I get it off.

 

[kryptto]

I realized that an extension bar will probably work given I have offset O2 sockets. If that doesn't work, I'll get a proper breaker bar, and if it's still stuck, a propane torch to heat the bung.

I'm not very mechanically inclined, but I am trying to teach myself to be, and this forum has been very helpful in doing that. Thanks for the help, everyone, I'll let you know when I get it off.

so the propane torch IS the best way to break the "seal" of a O2, like Texas mentioned, be careful with the flame. There are a TON of YT videos that show the procedure.

 

[autoteleology]

Hi, just wanted to provide an update on this, even though it's minor it might help someone.

So, ultimately, all I needed was a really big torque wrench to break it loose (and I even managed to avoid busting my knuckles). This is what I used, it telescopes to a very long length and it also has the perfect angle to hang down from the O2 sensor socket and still be horizontal enough to provide efficient leverage when you pull.

https://www.amazon.com/gp/aw/d/B000CMJ2KU?psc=1

I also used Gibbs Penetrating Oil (courtesy of Project Farm's recommendation):

And here is the socket set I used (though I believe you can just borrow a set from Autozone or Advance Auto Parts): https://www.amazon.com/gp/aw/d/B07KT1GR7V?psc=1



This is probably all super novice stuff to most people, but I ask for help a lot here, so I try to give back to the forum however I can.

 

[kryptto]

All good - help - helps...

 

[Bronco2fan]

Hi, just wanted to provide an update on this, even though it's minor it might help someone.

So, ultimately, all I needed was a really big torque wrench to break it loose (and I even managed to avoid busting my knuckles). This is what I used, it telescopes to a very long length and it also has the perfect angle to hang down from the O2 sensor socket and still be horizontal enough to provide efficient leverage when you pull.

https://www.amazon.com/gp/aw/d/B000CMJ2KU?psc=1

View attachment 91285

I also used Gibbs Penetrating Oil (courtesy of Project Farm's recommendation):

And here is the socket set I used (though I believe you can just borrow a set from Autozone or Advance Auto Parts): https://www.amazon.com/gp/aw/d/B07KT1GR7V?psc=1

View attachment 91284

This is probably all super novice stuff to most people, but I ask for help a lot here, so I try to give back to the forum however I can.

That's funny, because that's the wrench I use for my lug nuts. I have 3 of them. Everything with a spare tire has one in it.

 

[autoteleology]

All good - help - helps...

I try to avoid creating this situation lol

 

[autoteleology]

That's funny, because that's the wrench I use for my lug nuts. I have 3 of them. Everything with a spare tire has one in it.

That's exactly why I happened to have it lying around only to realize it would work perfectly for this task. I got it for my truck a long time ago after seeing it recommended on Wirecutter

The Best Gear for a Roadside Emergency

We spent more than 60 hours researching what emergency gear you should keep in your vehicle at all times. Here’s what we recommend.

www.nytimes.com

 

[autoteleology]

Oh, and one last thing - replacing the O2 sensors did not in fact fix my P0420 code, it looks like I need a new catalytic converter to get rid of my check engine light.

It's not a priority for me to replace since we don't have emissions testing or inspections in Ohio (which is incredible given how cars fall apart here due to the massive amount of salt we use in winter), but if I do, any advice on what I should get?

I noticed that it wasn't even a category on car-part.com, and I figured they all just got recycled because the materials are so valuable, but apparently it is illegal to buy a used catalytic converter for reuse.

Also, would I be able to get a decent amount of money back by selling my old converter for scrap?

 

[BradM]

Oh, and one last thing - replacing the O2 sensors did not in fact fix my P0420 code, it looks like I need a new catalytic converter to get rid of my check engine light.

It's not a priority for me to replace since we don't have emissions testing or inspections in Ohio (which is incredible given how cars fall apart here due to the massive amount of salt we use in winter), but if I do, any advice on what I should get?

I noticed that it wasn't even a category on car-part.com, and I figured they all just got recycled because the materials are so valuable, but apparently it is illegal to buy a used catalytic converter for reuse.

Also, would I be able to get a decent amount of money back by selling my old converter for scrap?

Look at O2 Extender instead of new cat.

 

[autoteleology]

Look at O2 Extender instead of new cat.

Very nice, I appreciate that a LOT. Thank you for the advice!

I purchased this one, an adjustable right angle adapter, because of the layout of the sensor makes the positioning very finicky. I'll report back how the order process goes, if it fits properly, and if it solves my issue.

O2 Bung Extender

This is an O2 bung extender that can help with fitment in the downpipe tunnel. It is made from Stainless steel, has straight and a 90 degree bend so you have two options for the best fitment. The 90 degree extender angle is adjustable so it can fit in any position. Not for use on primary O2 sensor.

zzperformance.com