Hello,

I just threw a P0430 code and apparently the passenger side Catalytic converter has choked.

Does anyone have any experience buying aftermarket replacements?

I'm looking at Magnaflow and they offer two options. I believe one is CARB legal and one is not.

See here for details:

https://www.carid.com/2008-hummer-h2...B%5D=MagnaFlow

Any input, thoughts?

 

Quick update. With the dealer wanting $2100 for a factory replacement and after speaking with a Magnaflow rep I went ahead and picked up part # 49679. It's an OEM direct replacement and by design (2 pieces) it should be relatively easy to put in as opposed to wiggling in the large one piece OEM exhaust. $753 shipped. ~$1300 savings.

 

I think you made the right choice. I think when i cross that bridge- im dropping in headers, pipes and mufflers and skipping the cats. No inspection where i live so nobody will be any wiser. I had an old s10 and we put straight pipes in and it was loud! I bet the h2 would sound great!

Let us know how it all goes together!

 

I have these:

https://www.afcodynapro.com/DYNATECH/895760119

paired with this:

https://www.afcodynapro.com/DYNATECH/2120267642

No complaints so far
(blackbear remap, and Borla backbox)

 

If I was prepared to replace the whole exhaust system that's what I would have pursued but for now I'm content to get it working correctly and addressing any other little gremlins the truck has. Next year I have a number of upgrades planned to most of the suspension pieces, brakes etc... to prep it for a trip to Moab.

 

I actually saw those cats during my search. Looks like a decent setup. Glad to hear there haven't been any problems. The dealer tried telling me that with anything other than factory parts I was going to have problems. This is only true to a point and the Magnaflow pieces look to be pretty good quality.

 

Looks like the 2008 and 2005 models have different arrangements, I did the job myself with Magnaflow Semi-Universal CATS but it involved cutting, aligning and welding, quite some effort but it worked.

Anyway here are some of the key points:-

• The manifold nuts can be very tricky, it took a high power air tool, lots of penetrating oil and patience.
• Take the opportunity to change the lambda sensors at the same time, buy a good extractor tool and tap to clean up the threads.
• Be sure to break-in the CATs, dont just drive-off. Read this procedure which is worth doing at least twice allowing the endgine to completely cool down in between. Here is
  a video
  which is well worth watching.

My CAT was completely plugged (a bucket of sand) but it took more than just one P04x0 code to convince me.


Good luck with the new CATs.

 

Great info thank you. Coincidentaly I just did this repair on my Trailblazer and didn't follow a break in procedure. Wish I knew. Hopefully this swap goes smoothly. I assume there will be a lot of braces in the way and hopefully accessing the O2's to unplug them isn't to bad. The two piece design should make for a much easier installation. On the TB I had to remove the driveshaft and fuel tank to get the new 1 piece part in.