2010 Equinox LTZ V6 - Catalytic Converter (Back of Engine) Replacement Procedure
 

I have been to the dealer and they have told me that I need to replace 25800888. CONVERTER | Genuine GM | 25800888

Anyone have the procedure for this?

I am looking for procedure, torque, and what gaskets I would need.

I'd think this would be covered by the 8 year/80,000 mile emissions component warranty. Since you're asking I'm betting that (unfortunately :( ) your Equinox has more than 80,000 miles on it. I was able to determine the part number you provided was for the back (right, firewall side) catalytic converter so I've attached three PDFs that should contain the info you need.

Attachment 8046
Attachment 8047
Attachment 8048

Thanks!!!

This will be my first time taking this thing apart. On the Flex Pipe Replacement it talks about removing the Front Lower Control Arm Bracket Brace. Do you have the procedure for that too? Or is it just simple?

Also do you have the Heated Oxygen Sensor Replacement - Bank 2 Sensor 2?

I think I see what it is now. It is just a bar across the bottom.

I guess for the other I just need the torque on the O2 sensor for reinstall.

Found it
 

I found the docs. Here.

Does anyone know what it means to transfer both o2 sensors?

Do they mean measure?

I'd say they mean transfer them with "transfer" meaning remove the oxygen sensors from the old parts and install them in the new parts as necessary.

I get it now. That makes sense. Anyone want to confirm?

So the reason I know my converter is bad is because I have had it in for diagnostic. That is, they observed a sensor 2 bank 2 'movement'.

After doing more and more research it seems highly unlikely that any o2 sensor is bad. A P0420 99 percent of the time means bad converter.

I think the cause, after reading, was the thousands of miles I drove with bypassed Mass Airflow and Airtemp sensors that are located in the air filter/intake box. They were bypassed because a Chevy tech did not tighten the clamp on the intake tube to the box.

This means that the engine was getting extra unmetered air into the intake and the ECM was compensating for this by dumping extra fuel into the intake for thousands of miles. This burnt that converter right up.

The reason I tell you this story is to ask:

Should I replace the O2 sensors also? The vehicle is at around 96k+anyways.

I have a hard time believing that a loose clamp would cause the engine to receive that much unmetered air. If the air intake hose was partially or completely disconnected it would be plausible, but not with just a loose clamp. If you didn't notice much of a drop in fuel economy (as determined by actually calculating it; not just going off of the DIC reading) then it wasn't a very significant air intake leak and certainly didn't make the engine run rich enough to burn up your catalytic converter.

In your case all the oxygen sensors are identical parts. You could try swapping one of the other sensors with the one indicating P0420 to see if the issue persists. In my experience I've found that a P0420/P0430 code is usually caused by a bad downstream O2 sensor. This is comparable to a bad upstream sensor falsely indicating a lean running condition. A bad O2 sensor usually generates a lower voltage when they start to go bad. If the sensor is upstream the computer interprets the low voltage as a lean running condition and subsequently triggers a P0171 or P0174. If the bad O2 sensor is downstream the computer triggers P0420 or P0430. Most exhaust shops have the ability to sniff test your exhaust to confirm whether or not the catalytic converter is bad. The dealership should have that capability as well.

The clamp was completely loose.

Anyways.

Lets say I replace both sensors and it does not fix it. Will they be at any risk of being destroyed before I can get a new converter in it?

As I said before, all of your oxygen sensors are identical parts. Knowing this, rather than install a new sensor, I would just swap the two downstream O2 sensors around, clear all the codes, and drive until the CEL comes on again. If you then get a P0430 code, this tells you the O2 sensor you moved to the bank 2 side (front of vehicle/radiator side) is bad. If the P0420 code comes back then it is probably a bad catalytic converter.

To answer your question, the O2 sensors would not be damaged at all. To add to this, you only need to replace the one O2 sensor that is bad. It won't hurt to replace them all, but it is unnecessary.

Again, I would be very surprised if your catalytic converter is bad. You want to be certain it is in fact bad because it will cost you over $500 in parts alone to replace. For comparison, one replacement sensor is only about $55 (AC Delco p/n 2134553 shipped from RockAuto). The only brands of O2 sensors I use are NTK, Denso, or AC Delco. I'm pretty sure your Equinox came with Denso sensors from the factory. The AC Delco replacements will probably be Denso parts in an AC Delco package.

Although AC Delco is the brand of most OEM GM parts, many AC Delco parts are manufactured/supplied by different companies and just have the AC Delco brand on the package.

Can someone tell me what the 3rd 'converter' after the y pipe is on my vehicle? Is it just a resonator. The guys at GM parts had no idea and did not want to do the work to tell me. It was called a converter in the parts manual.

It is exactly that, a third catalytic converter. It is item 6 in this diagram. Having the exhaust go through two catalytic converters is common practice on many newer vehicles.

Why would it be unmonitored?

I don't know the answer to this, but it is common for them to be unmonitored.

Can someone tell me which converter is bank 1 and which is bank two?

You should know this by now. :)

The "bank" refers to the bank of cylinders being identified. Bank 1 is always the bank containing cylinder #1 in the firing order. In your case, Bank 1 is the rear/firewall side cylinder head. Obviously, Bank 2 is the opposite bank; in your case the front/radiator side.

So:

Front Bank= 2-4-6 (near radiator)
Rear Bank= 1-3-5 (near firewall)

Do you know what to search for in the OEM service manual to get a diagram of the cylinder numbers?

The info you provided is correct. The service manual doesn't have a diagram. It just provides a description under the topic "Engine Component Description (LF1 or LFW)":
I was able to find a diagram from another reliable source (Wells Search Parts Catalog).

Attachment 8119

Replaced
 

Ended up getting the correct converter replaced and the code has went away.

Thanks for all the help!