Discussion: O2 and Cat

Did you replace that cat. converter? Looks like the hole where an O2 sensor used to be. I need to replace the cat on my Subaru and I'm dreading the exact photo you showed (a rusted coupling). Did you have to cut those bolts off?

I replaced one of my O2 sensors a couple of years ago. Had to get a special wrench to reach it - a crow's foot. Woohoo!

The special wrench is a necessity, I don't even think a crow's foot would have worked for me.Bosch, and others, make a special O2 sensor tool. That hole and mess is my failed attempt to remove the sensor from that Cat.
I cut the bolts off with a Sawzall, but even then it was difficult because of the angle I was working under the car. Would have been fine if I'd had a lift.
I use Never Seize on the sensor threads.
Has your Cat failed, and you can't pass inspection?

I have a scan tool (home-built from kit!) and used it to scan the O2 readings after I got a 0142 emissions code. Decided the forward O2 was bad and replaced it. Reset the code, but it came back almost immediately. Its intermittent, and usually once a year in winter it goes off for a week or so. I squeeze in an emissions test during that week every 2 years and it passes. But its annoying having the light on all the time. Next step is to replace the cat (dual cats, with a pipe between them). Based on other folks experiences, that probably won't clear the code either, but the heat shield on the forward cat rattles and my jury-rigged clamps to stop the rattle keep rusting off, so just to eliminate the rattle I want to replace the cats. Now that I have a garage and a new florescent light fixture installed (last week) I'm ready to get after it. Will probably order the cat from autopartswarehouse. Got my brake rotors from them a while back. Seems like a good operation. The cat will certainly be in a funny looking box :)

I don't have a sawsall, but this is the perfect excuse to get one. They're great fun. We had a Milwaukee one at the observatory. Used it to salvage the plywood from shipping pallets. I wonder if they make a turkey carving attachment - dual use! I could probably get by with the dremmel or sabersaw in this case though.