Car Problem Reports

Mercedes-Benz E320 Failed Exhaust Catalytic Converter May Cause Rattle From Beneath Vehicle

Mercedes-Benz E320 Problem
9 Reports
Me Too

Model Years Affected: 1996, 1997, 1998, 1999, 2001

Average Mileage: 159,571 mi (66,000 mi - 210,000 mi)


When the engine is running, but the vehicle is not moving, a rattle heard from beneath the vehicle could indicate that one of the exhaust catalytic converters has failed. The substrate (the internal part of the catalyst that reduces emissions) can loosen and bounce around inside the canister section of the converter—the defective unit will need to be replaced. If this problem is ignored, the substrate can break down and reduce to a size that plugs the outlet pipe, which will cause a sudden loss in power.

  • Visitor, , 130,000 mi


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  • Visitor, , 66,000 mi

    rattle coming from the canister after the cat.

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  •  Rookie

    Familiar rattle due to a faulty catalytic converter. The engine power is unchanged and it still passes the California smog test. Currently, the rattle has stopped so until the mpg or engine power significantly changes for the worse I'll keep driving until the wheels fall off the chassis. I've looked into options to replace the catalytic converter but the cost still isn't reasonable enough to proactively fix the issue at this stage.

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  • Visitor, , 190,000 mi

    Rattle in cat pipe and falling apart. Mercedes Benz replaced cat pipe and rattle was louder 2 days later.

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  • Visitor, , 141,000 mi

    Rattle inside the exhaust pipe after the converter when engine is running. Not fixed.

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