What Causes a Three-Way Catalytic Converter to Fail?

[RachelAnn]

The causes of three-way catalytic converter failure include: 1. Use of leaded gasoline: Tetraethyl lead in leaded gasoline causes significant environmental and human health pollution and damage. It also deposits on the active surfaces of the oxygen sensor and catalytic converter in the catalytic device, leading to 'lead poisoning' of the oxygen sensor and greatly reducing the purification efficiency of the three-way catalytic purification device until it is damaged. Long-term use of leaded gasoline can even clog the honeycomb catalytic converter in the catalytic device with tetraethyl lead. 2. Use of lubricants or additives containing lead, silicon, or phosphorus: If harmful components mixed in the lubricant come into contact with the catalytic conversion device, it can also cause the three-way catalytic device to fail. 3. Use of sealants containing harmful components like lead and silicon: Engine repairs often require the use of many sealants. However, if sealants containing the aforementioned harmful components are applied to areas such as the intake manifold gasket or oil pan gasket, it can poison or even disable the three-way catalytic device. 4. Overheating of the three-way catalytic converter: The working temperature of the three-way catalytic device usually should not exceed 800°C. If a cylinder in the engine has poor combustion, the exhaust will contain excessive unburned fuel gases, which can cause the three-way catalytic device to fail or be damaged due to a significant increase in working temperature. 5. Severe impact: A strong collision can break the catalytic converter core and render it useless.

[McNathan]

Last time my car's catalytic converter went bad, causing the engine to sound strange and consume more fuel. The main reason was that my old car wasn't properly maintained, leading to delayed engine ignition, which allowed unburned gasoline to enter the converter and damage it. Also, I often drove short distances, so the converter didn't have enough time to heat up and clean out carbon deposits, eventually clogging it over time. Using low-quality gasoline or fuel with many impurities can also corrode the internal materials more easily. A friend of mine had a collision that dented the pipe, affecting airflow. In the end, catalytic converters are quite delicate—you need to regularly check the spark plugs and fuel system. If it fails, the car won't run smoothly, emissions won't meet standards, and you might face fines for exceeding pollution limits, not to mention worsening air quality. My lesson is: don't skimp on small expenses, replace it when needed—safety first.

[LeFrancisco]

As someone who frequently deals with car issues, I see catalytic converter failures quite often. The main causes include engine malfunction, such as faulty spark plugs or fuel injection system problems, leading to incomplete fuel combustion that flows into the converter and burns, damaging it. Using fuel with high lead content or dirty fuel can cause deposits or poisoning on the converter's surface, clogging its pores. Additionally, structural damage from vibration or impact, or excessive carbon buildup from long-term high-load driving can also be culprits. Symptoms to watch for include unusual exhaust odors, failed emissions tests, and reduced vehicle power. For diagnosis, it's best to visit a professional shop to test oxygen sensors and pressure changes with specialized equipment. Replacing a catalytic converter isn't cheap, but delaying repairs may cause additional engine damage. Including this inspection in regular maintenance plans is crucial. I recommend car owners periodically clean carbon deposits and adjust driving habits to avoid frequent short trips.

[KevinRose]

Three-way catalytic converter failures are highly destructive and exacerbate air pollution. I've observed that the primary causes are often improper engine maintenance, such as delayed ignition producing unburned fuel, whose chemical reactions damage the catalyst coating. Additionally, low-quality fuels containing lead or sulfur can poison and deactivate the catalyst. Vehicle aging corrosion or physical damage from bumpy roads also contribute. These issues not only cause vehicles to exceed emission standards but may also increase fuel consumption and degrade acceleration performance. Everyone should pay attention to checking exhaust pipe conditions; during routine maintenance, use high-quality fuel and avoid sudden acceleration to reduce failure risks. Early detection and repair not only save money but also protect our shared blue skies.

[SanKinsley]

I've had this issue with my car before. After the catalytic converter failed, the acceleration became sluggish, and fuel consumption noticeably increased. It turned out that unburned gas from an engine fault entered the catalytic converter and overheated it, causing the damage. It might have been due to bad fuel with impurities that clogged the system. Neglecting regular maintenance, like frequent short trips where the catalytic converter doesn’t get hot enough to burn off deposits, can gradually lead to blockage. Some people have experienced deformed exhaust pipes, which disrupt airflow and also damage the converter. The lesson is: if you hear unusual noises or smell something odd, get it checked immediately—don’t delay. A repair shop can diagnose it with tools. Delaying repairs only makes driving more troublesome later. Saving time by addressing issues promptly is the way to go.