[Extreme Speed AZ]

This is my first post, so please be easy on me.

After searching last night for quite a while, I was unable to find any threads on the O2 issue of GM cross threading from the factory.

I figured I'd go on ahead and make a post on this.

Preprep-
I'm using jacks to get as much room under the car as I can, as well as removed the exhaust from the 2nd cats back. Luckily my post cat O2 on the pass. side was easy to remove.

Tools-
22mm brake line bear claw, (I didn't have an O2 tool on hand as it grew legs and walked away with one of my friends)

6" extension (I'm using a 3/8" adapter to get a 1/2" breaker bar on)

1/2" drive breaker bar

Enough cussing to call any sailor out

HEAT! A torch will be your best friend.
---------------------------------------------------

Have patience, trust me you will need it. Unfortunately GM put one stud/nut connecting the cat pipes right where the os sensor is. In order to get the pipe off the O2 has to come out (Unless someone else can pipe up with some sort of fancy tool they use).

After getting a breaker bar on the O2 and heating the bung, WATCHING WHERE MY TORCH IS HEATING, I was able to get it snapped off, leaving totally mangled threads on the bung. I was then able to remove the pipe, and disconnected the O2 from the car. Getting a new o2 sensor today as well as a thread repair tool.

I currently have the cat pipe in a bench clamp, i surfaced the bung about 1-1.5mm to help give a fighting chance to this repair (I have measured absolutely everything from the O2 depth to the bung threading depth, this should work without any issues. I did this to help get rid of the messed up thread at the beginning of the bung, as well as promote a good sealing surface.) Ordered the thread chaser, and after a visual of the bung I believe this should work just fine.

I'll post pictures if anybody is interested.

[chevybill]

Please post your pictures.
Am i correct to assume your car is out of warranty?
What caused you to begin this repair?

[Extreme Speed AZ]

Originally Posted by chevybill

Please post your pictures.
Am i correct to assume your car is out of warranty?
What caused you to begin this repair?

Yes, I am out of warranty.
This all started because I am installing an AEM Wideband as we are getting a Hellion twin turbo kit soon and will want the gauge to monitor and tune.

I ended up pulling the entire pipe so I can lay a nice tig weld for the O2 bung. It seems many people are installing the wide band on the passenger side, however I went with the drivers side for ease of wiring as well as that side was just a bit easier to get off. That is, until I found the O2 issue. Which could've explained why that bank was running a bit rich. (It was leaking)

Taking pictures currently and will post them all at one time.

[ctrlz]

Originally Posted by Extreme Speed AZ

(I didn't have an O2 tool on hand as it grew legs and walked away with one of my friends)

(Unless someone else can pipe up with some sort of fancy tool they use).

After getting a breaker bar on the O2 and heating the bung, WATCHING WHERE MY TORCH IS HEATING, I was able to get it snapped off, leaving totally mangled threads on the bung.

O2 sensors are always a PITA. Always need some combination of special sockets, wrenches, and voodoo.

Glad you have the whole thing off so you can rework the threads.

[gtfoxy]

Originally Posted by ctrlz

O2 sensors are always a PITA. Always need some combination of special sockets, wrenches, and voodoo.

Glad you have the whole thing off so you can rework the threads.

Yep.

I’ve wrecked a few O2 sockets. Got to the point I just cut the wires & use a boxed end wrench with some heat on the bung.