I took off my exhaust from the precats to the y-pipe to check and see if they were busted up and causing this annoying rattle at low RPMs. Well, I couldn't get the nuts off that hold the precats+cat together so I said screw it and put them back on.

I also just changed my coolant and while the car warmed up I noticed an increasing stink. Like, way worse than before. As it warmed up smoke started coming up the engine bay and from under the car. I figured it was the penetrating oil I sprayed on the nuts to try and get em offbut it didn't go away after a while. I looked underneath and holy ****, my precats are glowing red! There's also some smoke coming out of my...radiator fill spout

So to summarize:

-major exhaust leak from beneath
-exhaust leaks from rad fill spout
-red-hot precats

What the hell is my problem? Clogged cats plus leak, but what explains the exhaust from rad fill spout?

 

Did you put the Thermostat In Right?>
it should be in with the point UP.

 

Yep, I put it in as the FSM said to, with the jigglepin properly aligned etc.

 

Upon thinking about it overnight, the "exhaust" from the radiator was actually air bubbles and steam because it was so humid out. Makes sense...right?

I'm going to pull the precats off today and try again to get em apart, maybe with a liberal application of heat and penetrating oil they'll surrender their treasure.

 

Alright, I think I figured out the cause for the red-hot exhaust. After about an hour of hauling on the nuts I managed to get the precats apart. The first precat (closest to the engine) was completely empty. The second's honeycomb was cracked and uneven, so I rammed a breaker bar in there, broke it all up and dumped it out.

The main cat's honeycomb moves a bit when I tip it back and forth. Is this supposed to happen (slight bit of movement), or is it liable to break and clog? I would post pics but just before I went to take them I dropped my (shitty, thank God) camera on the concrete garage floor and it broke. Should I bust apart and empty the material from the main cat, and will it affect my car's performance at all? How much louder would it get?

 

The ceramic honeycomb is not supposed to move back and forth. I'd say it's on its way out. The car will be noticeably louderwith it hollowed out, but you will see a substantial power gain with it gone. The stock cats are pretty restrictive.

 

Alright...as long as it's just noticeably louder and not deafening. Then again stock manifold and my mufflers should keep it from being TOO loud.

I'm pretty excited that this is the reason my cabin would get really warm after driving for a while! If this fixes it it'll make summer driving so much more enjoyable.

 

I've still got the split air pipe and everything on there, will the emissions system no longer doing...anything emissions-wise cause any issues?

 

Update: Put it all back together, and found the leak! It's from the front end of the second precat. I'll likely buy a set of headers + presilencer over the summer to replace these rust cans. Still glows a bit and I have no idea why...maybe I'm running rich and the excess fuel is being burned in the precat?