Glenlivet12

After having another mechanic look at my rattling exhaust, he concluded there is no leak, but rather the inside of the cat is rattling. He is surprised there is no CEL. I just did some searching and found a Youtube video with the same noise and same diagnosis, so I guess I am cat shopping. I could apparently just leave it, since it will pass VA emissions because it 1) isn't showing a CEL and 2) the exhaust is not leaking, but the car sounds like a heap destined for the junkyard the way it is, so I'm looking to fix it.

Is there any feedback on aftermarket cats for the D16Y8? Magnaflow? Bosal? Theoretically they should be fine since they are direct fit, but I've read that some models are more sensitive than others to an aftermarket cat and can result in codes. I'd really like to avoid buying an OEM cat due to how pricey they are.

Former User

Given the lack of a CEL (code P0420), I think the noise may actually be caused by a loose or cracked exhaust heat shield. This is a very common problem for our Civics, and is much less expensive to fix than buying a new cat.

Glenlivet12

Mechanic said he clamped down the heat shields and everything else that could rattle, since the cat was the last thing he thought it was due to no code.

Noise is identical to this video:
The amount of noise is also dependent on the exhaust warming up. Cold start and idling, the exhaust rattles like crazy. Once it is warmed up, it doesn't rattle, and is just noisy under throttle.

Former User

The tests you mentioned are not absolutely definitive. It's pretty easy to remove the stock cat and pick it up and shake it to verify the internal rattling noise and to see the cracked and melted substrate.

mechanix619

Cats usually don't go bad without throwing a CEL like RonJ@HT stated.

Unbolt either side of the cat and look inside.

If you're dead set on listening to the mechanic without verify than the Mangaflow would be a good choice.

doctorake

If you are getting a new cat I have a magnaflow welded into my system after the stock b16a header. I am running a p30 obd2 del sol ECU on a JDM b16a. It throws no coeds and I had no problem passing emissions and safety in Va.

Glenlivet12

I believe he said he took it off and saw it was melted inside. I'll double check when I pick it up, and maybe take it off myself.

Assuming the guy is right, I just wanted to determine if I really needed OEM or if there was some aftermarkets that worked as advertised. I've read with Toyotas that they are very sensitive to aftermarket cats. I'd like to think a direct fit unit from a name brand would work, but that doesn't always seem to be the case.

Telecatster

This one http://www.amazon.com/Magnaflow-2262.../dp/B000XRJXJO might work if yours is a cat back bolt-on.

If it throws a code (the secondary O2 sensor) you can use the double spark plug non-fouler mod http://www.6crew.com/forum/showthrea...-an-o2-CEL-Fix! It works for civics too. There are threads around the internet that state the specific part number (non-fouler) to buy at autozone.