Rattling Caterlytic Converter noise not as thought : )

[spiff]

Good evening from Mullion Cove Cornwall.

An update on our Citroen C5 2005 Petrol.

Service documents several years before we purchased the car mentioned a rattling catalytic converter.

I listened under the car and sure enough the noise was from the cat.

It also rattled as if full of dried peas if tapped hard.

We replaced the cat, the old one had three or so tear drop shaped 1/8 inch bits floating around in it.

The new cat did not stop the rattling noise when the engine was running, it sounded like a loose heat shield would but was not.

I returned the new cat and fitted the replacement, same trouble.

A stethoscope type device showed the noise to be louder closer to the manifold.

I believe that is where the problem lies, it appears there are separating plates or baffles in the section of the exhaust manifold, that connects the pipe to the cat.

The bits of loose metal in the original cat are probably from it.

The images attached ( brightened ) are of the same model manifold taken off line.

Also the comment of a seller as below, plus other reading suggests this is a problem with exhaust manifolds.

Used
“good used condition, internal baffles (which can rattle) have been welded (to prevent said rattling)”

God Bless Spiff

[white exec]

What a cheap and tinny looking thing!
Wonder whether anyone makes an after-market and better replacement?
Do each of those quadrants lead internally to the separate exhaust ports, or is it just at the exit, I wonder?

If it is just the plates at the exit that need a touch of weld, might it be possible to do the work from the underside with the manifold still in place?

[spiff]

Hallo Chris,

I think they lead to each port, as I tried to look inside with a camera, the type you can look in pipes with.

The left one appeared to turn that way for a while, but the camera was fixed focus and proved too difficult to use.

I have wondered about trying to remove them : )

Not sure of their purpose ?

God Bless Spiff

[white exec]

Hi Spiff,
If they do go to separate ports, it's probably a cheap attempt to either alter the exhaust note, or to prevent the output from one exhaust port hitting another. Once upon a time, there were swept manifolds!
Don't think it's internal reinforcing - all a bit (too) loose for that.