What are the symptoms of a failing catalytic converter?

2 Answers
VanJosiah
09/04/25 3:33am
The symptoms of a failing catalytic converter are: 1. Unpleasant exhaust odor; 2. Engine overheating and premature excessive wear; 3. Loss of engine power and abnormal noises. The catalytic converter is an external purification device installed in the vehicle's exhaust system, which converts harmful carbon monoxide, hydrocarbons, and nitrogen oxides from vehicle exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions. The causes of catalytic converter failure include: 1. Blockage due to deposits from ethanol gasoline, sulfur-phosphorus chemical complexes, lead-manganese metal deposits, or melting of the ceramic substrate caused by engine exhaust flames; 2. Loss of activity of the surface precious metals, rendering them ineffective for catalysis; 3. Prolonged exposure to high temperatures, leading to thermal deactivation.
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OGianna
09/16/25 4:44am
I've been driving for over 20 years and personally experienced catalytic converter failure. The main symptoms are the persistent illumination of the yellow engine light, which is really annoying. The car feels sluggish during acceleration, lacking power when pressing the gas pedal, and struggles when climbing hills - this significantly affects daily driving experience. Fuel consumption increases noticeably, for example from 8 liters per 100km to over 10 liters, wasting more money on gas. The exhaust often emits a pungent rotten egg smell, which is a dangerous sign of hydrogen sulfide leakage. If severely clogged, starting the car may become difficult, or the engine might overheat during summer driving, nearly causing breakdowns. If not addressed promptly, this problem can affect the entire exhaust system, making repairs more expensive. I recommend regular maintenance, using higher quality gasoline, and not letting an old car drag you down.
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