O2 sensor instalatio tips

Hi all,

My computer is telling me that I need to replace the upstream O2 sensor on my '03 V6. After doing a little reading, it seems that both the upstream and downstream sensors should be replaced at the same time, which I'm fine with. The issue is with the removal of the downstream sensor. It should be the easiest to remove, but there's a small shroud restricting access to the bolts.

Does anyone have any tips for me? I have attached an image for clarity.

 

Spray the nuts with penetrant for a couple of days first

 

That I will do, but I don't see how to get a wrench in there with that silly shroud.

 

You need to use an oxygen sensor socket. Looks like this..


Not that exact one but the correct size for the sensor. I forget what the size is.

 

Actually, I may be wrong. If you peek over that shield you'd see 2 nuts, Probably 8mm or 10mm. Those are tightened on 2 studs that are coming out of the exhaust pipe. Once you remove the 2 nuts, you'll be able to pull the sensor out.

It'll look something like this..

 

Yes, there are two nuts in there and you are correct in saying that removing the nuts is the correct way to remove it (the replacement even comes with the gasket). The issue is that shroud/shield prevents wrenches from getting into there. I have seen a few "how to's" on youtube, but none of them have that shroud, which leaves me puzzled.

 

I believe once you remove the 2 nuts, the shield will come off with it. When I replaced mine sooo many years ago, I never reinstalled it. In fact I think I have it sitting in my toolbox with a bunch of other spare parts.

 

Yep, here it is..


Probably a common thing that everyone does when replacing that sensor. Is to not reinstall it which is why you probably don't see it in any videos.

Just get a socket with a small extension in there and you should be good to go. Your choice if you actually want to reinstall it or add it to your bottom toolbox drawer like me.

 

I used a 1/4” ratchet an extension and a deep socket, if the nuts give you trouble coming out, rock back and forth, spray penetrant and repeat

 

I reused the shield

 

When I put my truck back together, maybe I'll remember to put it back where it belongs

 

Sounds like OP is saying the shroud is blocking access to the nuts.

I looked at mine which has never had O2 sensor replaced and there are no shrouds. I'd cut it off to access the nuts. New O2 will come with shroud (or not) I believe. But they didn't have one from factory. GL~

 

Part out?

 

That is funny! Just an afternoon of wrenching between you and your daily driver!

 

My problem is that I need to use a deep dish socket to get past the shroud but the handle of the socket wrench comes up against the frame, perhaps as I look at a lower profile socket wrench with a pivoting head may do the trick.

 

It can be removed with the shroud in place

 

Do you have a ratchet with a swivel head?
Or just a swivel?

 

Nah, I'm too attached. I'm the original owner. Cracked head gasket at 130k. About 2 yrs ago is when I started disassembly. It ended up becoming my project truck so intentions are to rebuild the engine and piece her back together bit by bit. Only thing that would get me to sell it would be to sell it "as is" for a crazy insane price that nobody would want to buy it

 

I think I will pick up a ratchet with a swivel head. Hopefully that will do the trick.

 

Its not that big of a deal, youre overthinking it....
shallow socket with a 3" extension is all you need...
If you need to tweak the shield some to get access it can easily be done so & wont be the end of the world, will bend right back into place afterwards...

Dont force those nuts, cousin snapped the studs in the pipe on his 4runner....
His wasnt a rust bucket, cali truck...