2002 Buick Lesabre Rattle noise from area of catalytic conv

HANAGAN

MEMBER
2002 BUICK LESABRE
6 CYL
FWD
AUTOMATIC
83,000 MILES

Recently I have noticed a rattling noise coming from the general area of the catalytic converter. This happens when I step on the gas, , and I notice it more when the car is still in the garage.
My local mechanic says that the noise is coming from the converter. He said it is shot. It is out of warranty by 3000 miles. He told me that the entire exhaust system from the catalytic converter all the way back to the rear of the car is one welded piece and the whole system has to be replaced for $720.00.
Does this sound correct? Is it possible to change just the converter? Do the parts have to be purchased from GM? If a piece is flopping around in the converter, can I still pass the Illinois State's emission test. The bottom line is the noise doesn't bother me and I would prefer not to spend the money at this time. Thanks for you help.

1 Reply

ZACKMAN

MECHANIC
4,202 POSTS

More than likely the noise is coming from the heat shield for the converter. The weld after a while has rusted and broken off of the cat and vibrating as the engine running.

You can go to a muffler shop such as Midas and have them take a look at it. If it was me, I would crawl under the car with two of the biggest metal clamps I could find and just clamp the heat shield back to the cat, and be done with.

If it is in fact your cat needs replacing, your car would run really rough with no acceleration, backfiring and the check engine light will be flashing. And obviously will not pass your state's emission test. Midas can just replace the cat by itself, part does not have to come from GM, Midas carries it or you can purchase your own at your local auto parts store ($150) or online ($100.00 at rockauto. Com)