I have a catalytic converter breaking and I am getting it fixed in a few months. It rattles all of the time and is very loud and annoying. I have a 2004 v8 5,4 triton. Would knocking out that honeycomb in the cat be a temporary fix? Is it ok if i only do that to one of the cats. Will it affect how it runs or anything?

 

First of all make sure it's not the outside heat shields on the CATS making the noise. VERY COMMON! removing the honeycomb is not a fix. If removed, it will stop you from having the small pieces that break up from clogging up the down stream exhaust parts. It will throw off your O2 readings and set a code and engine light.

 

So you don't think that'd would help even if I only do it for 2 months? And how do I find if its the heat shield?

 

I just checked and there isn't a heat shield so that's not the problem.

 

if you hit the cat's with a rubber hammer or something when they are cold to see which ones are loose. cleaning out the inners of the bad one will set a code but you should be able to drive it that way until you have the bucks to repair the cat.

 

It doesn't always work but I've found that tapping around with a hammer or sometimes just the palm of your hand will produce the same sounding rattle. You can often move around the assembly and follow the rattle right back to a loose bolt or other source. This generally works on anything that rattles and not just exhaust systems. the other thing that you can do is to just press down on different areas while the rattle is happening and if you find or even get near the source the rattle will stop. This works particularly well on rattles coming from interior panels inside of the car. It's generally hard to listen and tell where they're coming from but if you just start pressing things down you can usually find them quickly.