996C4S Oil Change/Rattle in Engine Bay

Had a buddy drop off his 996C4S tonight for an oil change in preparation of a trip.  As soon as I started the car, I noticed a rattling coming from the engine.  Immediately IMS jumps into your head, but I didn’t think it could make that much noise and keep running, lol.  The quick diagnosis…..shut the car off and close the driver’s door…….rattle.  So definitely something not related to the motor.  My initial thought was the baffles had come apart in one of the mufflers as they do on occasion in the 996, but they were fine.  A rubber mallet eventually found the cause of the noise, which was a bad catalytic converter on the passenger side.  I pulled it thinking maybe a baffle had come loose in the muffler and made it’s way to the cat, but once I got it out of the car, it was obvious that the honeycomb was sliding around in the housing.  The good thing is that 3 major components of the emissions systems are covered by federal warranty for 8 years or 80k miles.  This includes the catalytic converters, the ECU, and the OBD.  By law, the dealer will have to replace it and cover 100% parts, labor, and diagnosis.  Sooooo back on the car and off to our friends at Aristocrat motors.

Here you can see the core of the catalytic converter has slide back and forth within the housing.  The core is just out of site to the left.

C4SCatCatalytic ConverterEngine RattleFederal Emissions LawPorsche

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