Twofish

Hello.
I know it is next to impossible to diagnose a rattle over the internet but I'm wondering if anyone else has had this same issue.
The car is a 2001 E430 with 88k miles.
The shift rod linkage bushings were shot so I replaced those a while ago. Interestingly enough, the rattle did change but it did not go away.
The rattle is pretty much constant and it comes from the area right around the rear cats.
I have been under the car with the engine running and a stethoscope and one of the cats does seem to sound a little on the crunchy side but if memory serves these cats have a reputation for being solid and should last as long as the vehicle itself. I could be wrong about this.
I really want to avoid replacing anything that does not need to be replaced and I am pretty sure it is the cat that is making the noise.
Before I drop a bunch of money on a new one I want to rule out the rubber discs at each end of the drive shaft. They appear to be in good condition but I do not know what the symptoms are for the gradual failure of these things.
The car has no performance issues. It accelerates and shifts just as it always has. No CEL or malfunctions lit up on the dash.
If it is a faulty cat, does anyone who lives in California know if I can eliminate the cats altogether and still pass CA emissions?
Thanks in advance for any advice or suggestions.

Plutoe

put the car on a lift and start grabbing and shaking stuff----wada you find

khomer2

Finding any noise issue can be like looking for a needle in the haystack, in most cases.
You need a second set of ears, even a third, to get closer to finding it.
Record the sound, from different areas, and post a link(s) so members can hear it for themselves.
A simple post describing what you hear, does nothing for the readers, except to play 'whack-a-mole'.

Twofish

I went to an exhaust shop this afternoon and the guy wasn't busy so we put the car on the lift and started shaking things around just like Plutoe suggested. It is, indeed, one of the rear cats that is making all the racket. Money is a bit tight these days so I'm thinking about cutting it open and pulling out the loose pieces, then welding it back together until I can have the cat replaced. Hard to do on my back with the bottom of the car just a few inches from my face but I'll give it a shot. If it doesn't go as planned I'll just bring it down to the guy who helped me today and have him install a new one. I don't have to have it smogged until October of 2022 so I have some time to do it.
I asked the guy about eliminating the cats altogether and he said that it won't pass emissions, which is also what I expected.
The guy at the shop was very helpful so I hope it is ok if I let people know that the place is called Exhaust Specialist and is located at 1261 California Drive in Burlingame. He let me spend some time examining the bottom side of the car while it was up on the lift, which I appreciated.
He said I can bring my own parts and he can install one cat for about $120 or both for $200, or he can get the parts for me. His parts guy wasn't in so he didn't have a price for me.

khomer2

Your rear cats, I dont believe, have O2 sensors, so you should be able to delete them without issues.
Check with your local state regulations on emission testing, if any. Also, some may or many not require visual inspection of these, if you have state emission testing.

Twofish

I was thinking the same thing.
The O2 sensors are upstream from the rear cats.
They might do a visual inspection of the engine compartment but they don't put the car on a lift and they don't do a visual inspection of the cats. I might just go ahead and delete them and see what happens.
California emissions are pretty ridiculous. I have a 2015 diesel powered F250 and I had to pay $90 to have it smogged before I could renew the registration for 2016. All the guy did was walk around the truck with a mirror on a stick and look to see if I had modified the exhaust in any way. Then he over inflated all four tires. He never even started the engine. It's a money grab.