I've got a rattle in my exhuast system. Makes ego killing rattle at idle and during inital shift into 1st gear.

Tech up at Scanwest thought it was the middle muffler... a baffle loose or something. I got down on the garage floor and tapped around with the end of a broom. Rubber mallet would have been better, but this is was I had on hand.

Tapping the middle muffler produced no noises. But tapping the cat... ouch! Sounds like there's a few nuts or some crap bouncing around in there! :roll:

This is a BSR 3" Downpipe and sport cat. I am groaning about replacing this damn thing.

My question is, not knowing what the inside of a cat is consists of, what the heck could be in there making all the racket? Could I plugin the 3" downpipe and cat from genuinesaab and it will fit with the bsr 2.5 catback?
http://www.bsrab.se/products//4006318/
http://www.genuinesaab.com/catalog/product_info.php?cPath=56_24&products_id=403

Here's a video of my tapping and the rattle. http://www.youtube.com/watch?v=fjOmr_MM_dI

EDIT: Also I should note that I have never gotten a CEL warning about the cat not working properly.

[QUOTE=SaabNW]
...My question is, not knowing what the inside of a cat is consists of, what the heck could be in there making all the racket?...]

platinum! no really there is platinum in there. But the structure there is a honeycomb, reminds me of almost a ceramic or very hard foam type material.

ive heard that it could be just the cat tag hitting the heat sheild not with your particular setup, but from experience on other cars

Hahahahahaha I'm not sure why, but your video gave me a nice laugh. Anyways my bet is the honeycomb structure of the inside of the cat came apart some how. Maybe something gave it a good jolt to break its insides?

I can't say I know exactly what happens inside there, but what you're hearing sounds like the cat "death rattle". Typically a sign that your cat is done.

ive dealt with cat rattle for about 10 years in my car (a dodge truck) and never failed inspection or anything :roll:

I had a rattle like that in another car. It was from the metal tag telling all about the cat (this stupid car had two - :( ) I tried all kinds of ways of securing that stupid tag. Finally getting mad I opened the heat shield, took it out. Rewelded the heat shield on and no more noise.


Down side, the cat failed the following years inspection, that was from cracks in the side of it. Don't know if it was my welding or from going through a deeper puddle.

Had to replace both of them. :evil:

Copied from the original post from Saab NW :

This is a BSR 3" Downpipe and sport cat. I am groaning about replacing this damn thing.

Is the "sport cat" a replacement catatylic convertor ?
How long has this been on the car ?

If this is aftermarket, it cannot be very high quality.
The OEM seems to be much better..
Observe the heat on the temperature guage; if the convertor really breaks down, serious overheating can occur, as well as horrible running..

The cat is also from BSR. The entire aftermarket exhuast system has been on the car since may 2003. It was installed before I purchased the car.
Luckily no overheating, and never a CEL warning. Seeems to be working ok.
Copied from the original post from Saab NW :

This is a BSR 3" Downpipe and sport cat. I am groaning about replacing this damn thing.

Is the "sport cat" a replacement catatylic convertor ?
How long has this been on the car ?

If this is aftermarket, it cannot be very high quality.
The OEM seems to be much better..
Observe the heat on the temperature guage; if the convertor really breaks down, serious overheating can occur, as well as horrible running..