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2003 gmc envoy_sle_xl
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Discussion Starter #1
I'm trying to replace the front o2 sensor on the Envoy. The socket just slips and will not loosen it...any ideas how to get it off?
 

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2002 gmc envoy_slt
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3,203 Posts
I'm trying to replace the front o2 sensor on the Envoy. The socket just slips and will not loosen it...any ideas how to get it off?
Do you have the wrong sized socket or has the 'nut' now been rounded over? If the nuts is rounded, try a pipe wrench, large vice-grips or borrow a bolt extractor.
 

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2003 gmc envoy_sle_xl
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68 Posts
Discussion Starter #3
Do you have the wrong sized socket or has the 'nut' now been rounded over? If the nuts is rounded, try a pipe wrench, large vice-grips or borrow a bolt extractor.
I bought the socket from Autozone that's for them...so i think it's the right size. It's not rounded, the socket flexes and just moves. I can't get to the nut with vice grips...can I attach it to the part of the sensor that sticks out or will that break it off?
 

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2003 chevy trailblazer_ls
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5,268 Posts
are you sure youre trying to remove the right part?
Just in case
Should be located on the passenger side on the exhaust manifold.
You should be able to view it from the rt wheel well. you can turn the wheel to access it.
Im a little concerned that its bending the tool youre using.
they are usually hardened since they have the opening on them to allow the wire to not be damanged.....
Can you take a pic of the O2 sensor?
Can it be rusted on there so much.
I replaced mine at something like 130,000 and it came out very very easily.
 

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2002 olds bravada
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2,369 Posts
it will break off

if the sensor is in tight enough to flex the tool (assuming the tool is heavy duty) I would soak the sensor in pb blaster overnight, if that doesnt work I would heat it up
:iagree: I didn't have enough time for PB blaster to do its magic, so i just had the engine running for a couple minutes and it got hot enough for me to pry off. I parked in a garage with my feet pushing against the wall though..it'll take a lot of effort.
 

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2004 gmc envoy_sle
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399 Posts
it will break off

if the sensor is in tight enough to flex the tool (assuming the tool is heavy duty) I would soak the sensor in pb blaster overnight, if that doesnt work I would heat it up
:iagree:pB Blaster. Do it a couple times (assuming you're not in a hurry). Let it soak for a long time, overnight would be great. If that doesn't work, then try the heat, but remember to heat the manifold around it and not the sensor itself. You want the metal around it to expand.:m2:
 

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2005 chevy trailblazer_ls_ext
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2,667 Posts
I don't know if it's a west coast thing - but mine came right out too. Very little effort, no soaking it or anything. I did mine when the engine was overnight cold.
 

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2004 gmc envoy_sle
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I don't know if it's a west coast thing - but mine came right out too. Very little effort, no soaking it or anything. I did mine when the engine was overnight cold.
That's exactly it. Us midwest guys are in the salt belt. We know how to make plastic rust:rotfl:
 

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2005 chevy trailblazer_lt
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434 Posts
If you need help let me know. I will bring over my socket and give it a try, I will also bring a pipe wrench just in case. I changed mine last week and I expected a struggle, but it came out very easy.
 

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2002 chevy trailblazer_lt
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68 Posts
Go to auto zone and rent their o2 sensor tool. It comes with the socket and 2 other tools. I used the socket to get my orginal off 3 days ago. But had to use the other tool to install the new one. The other tools make it easier. Just had to slid a pipe on my ratchet for a longer lever arm.
 

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2003 gmc envoy_sle_xl
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Discussion Starter #14
are you sure youre trying to remove the right part?
Yes I'm trying to remove the right part...but thanks for double checking! It looked very rusty.

That's exactly it. Us midwest guys are in the salt belt. We know how to make plastic rust:rotfl:
Isn't that the truth! I'm orig from Erie and in the winter the Envoy changes from Tan to White! Not so bad down here in LC I don't think they know what salt is!

If you need help let me know. I will bring over my socket and give it a try, I will also bring a pipe wrench just in case. I changed mine last week and I expected a struggle, but it came out very easy.
Thanks, I will keep that in mind if I don't get it off this weekend.

Go to auto zone and rent their o2 sensor tool. It comes with the socket and 2 other tools. I used the socket to get my orginal off 3 days ago. But had to use the other tool to install the new one. The other tools make it easier. Just had to slid a pipe on my ratchet for a longer lever arm.
What's the difference between the two tools? The one I bought at auto zone is a short socket with the offset. I guess I will rent the set on the way home and see if that helps!


Would it be beneficial to do it when the engine is hot? Or would it be just as stuck?
 

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2002 gmc envoy_slt
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One other thought, not all sockets have the same number of faces or points on them. A 12 point socket on a 6 point bolt will have more play and be more likely to slip than a 6 point socket. If you're socket has more points than the head of the O2 sensor (I believe they're 6 pt, but not looking at one), make sure you're using a 6 pt socket or one with the same number of points. - Might be part of the problem, the O2 specific socket usually has the same number of points as the sensor.....they know how difficult it is to remove them at times.
 

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2003 chevy trailblazer_ls
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5,268 Posts
didnt occur to me that you were in the rust belt....
but I was expecting a tough time to remove mine- and in reality--- it was so easy--- that I actually had a harder time removing the plug....
no joke...
it really was harder to disconnect it- than it was to remove the O2 sensor itself.
the new sensor also had a bead of anti seize around it too... so make sure yours has it- or hasnt been wiped off.
 

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2003 gmc envoy_sle_xl
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Discussion Starter #17
- Might be part of the problem, the O2 specific socket usually has the same number of points as the sensor.....they know how difficult it is to remove them at times.
Yes I have the one specifically for O2 sensors, it's six sided with a opening for the wires.

didnt occur to me that you were in the rust belt....
but I was expecting a tough time to remove mine- and in reality--- it was so easy--- that I actually had a harder time removing the plug....
no joke...
it really was harder to disconnect it- than it was to remove the O2 sensor itself.
the new sensor also had a bead of anti seize around it too... so make sure yours has it- or hasn't been wiped off.
I was expecting an easy time to remove mine, bought the special tool, a new breaker bar....didn't work so well. I was bitching up a storm trying to get it unplugged...you can imagine how heavy that storm grew when I was not able to get the sensor off! I did buy additional anti seize just in case it gets wiped off.
 

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2007 chevy trailblazer_ls
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1,239 Posts
Cut the wires off of the old sensor and use a 6 point socket to remove it. Use the O2 sensor socket to install the new sensor.
 

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2003 chevy trailblazer_ls
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5,268 Posts
Cut the wires off of the old sensor and use a 6 point socket to remove it. Use the O2 sensor socket to install the new sensor.
why didnt any of us think about that...:bonk:

:thumbsup:
 

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2005 chevy trailblazer_lt
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434 Posts
The only issue is if he still can't get it out, then he throws a code if he tries to drive it. Just more hassles.
 
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