Secondary Catalytic Converter - Internal Rattle

Been chasing a rattle under my truck for a bit. I always thought it was the rearmost heat shield but it never went away.

Finally had my daughter start the truck while I was under it and put it in drive/reverse. Don't worry, I told her I don't have a life insurance policy or anything valuable.

The secondary catalytic converter is rattling inside of it.

Is there anything I can do about it other than replacement?

Does anyone else have this issue?

 

Not very common but common enough to see several Tacoma cat honeycomb come apart due to age or getting damaged/skid due to rock.

replace it or hollow it out of your state doesn’t require smog.

 

Colorado does require air testing.

Just trying to learn here: wouldn’t hallowing it out mess with pressures and/or the O2 sensor readings?

 

Yes.

If the state requires smog, your only option is to replace it.

 

Not all of Colorado. Just the Denver/Fort Collins metro area. You could solve this problem simply by uprooting your entire life.

FWIW I bought a Magnaflow CARB-compliant cat last year. It solved my P0420 and I've had no issues with it except for the price.

If things aren't too crusty under your truck, it's pretty easy to remove the cat and inspect for damage. Just be ready to put in new gaskets and hardware if you decide the cat is good--they're not meant to be reused.

 

the bolts/nuts on the cat are completely corroded. I think I’ll just deal with the rattle until I need to deal with more.

 

As the cat rattles it breaks apart and could plug the exhaust.

 

Buy property in Gilpin county. Do minimum to have a legal residence address. PROFIT.

 

Spend $200,000 instead of buying a $1000 part.

I’m in.

 

Does it have a good rythym? If so, leave it alone.

 

Exactly. I loved hearing that from people when someone complains about emissions. “Just buy some property in XYZ and register your vehicles in that county!”