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rattles are bad Posted by MJM [Email] ![]() ![]() In Reply to: Catylitic converter life span ?, neal, Sat, 28 Jul 2001 09:47:52 Members do not see ads below this line. - Help Keep This Site Online - Signup |
With proper care (ie, no leaded fuel), cats will last a long time. Over time, contaminents from cheaper fuels will build up inside and decrease performance. Vibration is also very bad for cats. The rattle you hear is either from a loose heat shield on the cat or exhaust, or is due to structual failure of the matrix inside. Cats have a thinwall precious-metal honeycomb inside. The precious metals work to clean the exhaust gases and the honeycomb is to give the greatest possible surface area. I read once that the "average" cat has an internal surface area about the size of a football field.
Bottom line - if it's rattling, then check it/have it checked out. That probably means that pieces of the honeycomb are floating around inside the cat. That can lead to partial or complete plugging of the exhaust, with all sorts of heating/mileage and pollutants issues.
Matthew isn't quite right, a good design cat is not much of a restriction on flow, and will certainly be better than a dying one.
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