For about 6 months the Metro had been making a rattling noise on startup (especially on a cold startup). I crawled under the car and started banging around on stuff and sure enough the rattle was coming from the catalytic converter. I was pretty worried about this because I knew how hard it would be to remove the bolts holding the exhaust to the manifold since these bolts are always horribly rusted. I had spent a few days trying to remove them on another Metro and I was definitely not looking forward to doing it again.

I grabbed some weapons (a torch and a can of PB Blaster) and went to work. I started the car to let the manifold heat up and held the torch on the manifold for about 5 minutes to see if that would help:

After only a few minutes of work the bolts came right out. I guess the Metro gods were smiling on me:

I flipped the cat upside down and took a look at what it would take to fix it:

I fired up the plasma cutter and in about 45 seconds I had cut an access panel:

When I flipped my DIY inspection lid open the problem was plain to see:

I'm not sure how much cat material is normally in there but I'm guessing there is some stuck in my muffler as well. If I have any problems with it in the future I might have to remove the exhaust downstream of the cat as well:

I cleaned up the edges a bit on the lid and the cat housing to get ready for welding everything back together:

Once again the welding was really hard for me. I don't know if it is my cheap equipment or my lousy technique but I spent quite a bit of time getting the plate back on. At some time I really need to work on winning the lottery so I can buy a nice Lincoln MIG. Anyway, the catalytic converter rattle is fixed - time to start working on the other 30 rattles: