{"id":9279,"date":"2022-08-23T18:08:53","date_gmt":"2022-08-23T18:08:53","guid":{"rendered":"https:\/\/www.automotiveguider.com\/?p=9279"},"modified":"2023-05-25T13:08:50","modified_gmt":"2023-05-25T13:08:50","slug":"what-causes-the-catalytic-converter-to-go-bad","status":"publish","type":"post","link":"https:\/\/www.automotiveguider.com\/automotive-guides\/what-causes-the-catalytic-converter-to-go-bad\/","title":{"rendered":"What Causes the Catalytic Converter to Go Bad?"},"content":{"rendered":"\n

The catalytic converter is one of the most important emissions control devices on a modern car and it plays a vital role in reducing emissions. However, this important piece of equipment can eventually go bad, causing a number of problems for the vehicle.<\/p>\n\n\n\n

But what causes the catalytic converter to go bad?<\/strong><\/p>\n\n\n\n

We did some research and asked automotive professionals to find out 14 of the most common reasons why a catalytic converter may fail. These include:<\/p>\n\n\n\n

  1. Poor engine maintenance<\/li>
  2. Age and mileage<\/li>
  3. Overheating<\/li>
  4. Faulty oxygen sensor<\/li>
  5. Unburned fuel in the exhaust system<\/li>
  6. Oil or antifreeze entering the exhaust system<\/li>
  7. Low coolant level<\/li>
  8. Bad spark plugs or spark plug wires<\/li>
  9. Damage to the honeycomb structure<\/li>
  10. Short trips<\/li>
  11. Road or structural damage<\/li>
  12. Fuel additives<\/li>
  13. Exhaust leaks<\/li>
  14. Faulty valve seals<\/li><\/ol>\n\n\n\n

    Sometimes, a failing converter can be repaired, but in other cases, it will need to be replaced.<\/p>\n\n\n\n

    In the next section, we’ll discuss each of these causes in detail as understanding the causes of catalytic converter failure<\/strong> can help you keep your vehicle running smoothly and help you avoid costly repairs.<\/p>\n\n\n

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    \"reasons<\/figure><\/div>\n\n\n

    What Causes the Catalytic Converter to Go Bad?<\/h2>\n\n\n\n

    There are several reasons why a catalytic converter may fail, including age, unburned fuel in the exhaust system, damage to the honeycomb structure, or faulty oxygen sensors.<\/strong><\/p>\n\n\n\n

    Let’s take a closer look at each of these causes.<\/p>\n\n\n\n

    Age and mileage<\/h3>\n\n\n\n

    Ideally, a catalytic converter is designed to last the lifetime of the vehicle, but it can eventually go bad due to age and mileage.<\/p>\n\n\n\n

    Over time, the honeycomb structure inside the converter can become clogged with carbon deposits, restricting exhaust flow and causing the converter to overheat. <\/p>\n\n\n\n

    In addition, the catalyst material can deteriorate, decreasing its ability to convert emissions.<\/p>\n\n\n\n

    Poor engine maintenance<\/h3>\n\n\n\n

    One of the most common reasons for catalytic converter failure is poor engine maintenance.<\/p>\n\n\n\n

    It’s important to keep up with regular oil changes<\/a> and tune-ups to prevent deposits from building up in the engine and clogging the converter. Using the wrong type of oil or fuel can also lead to deposits that can damage the converter.<\/p>\n\n\n\n

    Most modern cars will periodically remind you to service the engine, so be sure to follow the manufacturer’s recommended maintenance schedule.<\/p>\n\n\n\n

    Overheating<\/h3>\n\n\n\n

    Catalytic converters work closest to one of the hottest parts of your vehicle – the engine.<\/p>\n\n\n\n

    As a result, it can become damaged if they overheat due to a clogged filter, restricted exhaust flow, or an overheated engine.<\/p>\n\n\n\n

    If the converter becomes too hot, the honeycomb structure inside can melt, damaging the converter beyond repair.<\/p>\n\n\n\n

    Faulty oxygen sensor<\/h3>\n\n\n\n

    The oxygen sensor is responsible for monitoring the amount of oxygen in the exhaust system.<\/p>\n\n\n\n

    If it senses that there’s too much or too little oxygen, it will adjust the air\/fuel mixture accordingly.<\/p>\n\n\n\n

    If the oxygen sensor is faulty, it can cause the engine to run too lean or too rich, which can damage the catalytic converter.<\/p>\n\n\n\n

    Thankfully, most modern cars will immediately throw a “check engine light” error code if the oxygen sensor isn’t working<\/a> properly or if your catalytic converter is bad. <\/p>\n\n\n\n

    You should take your car to a mechanic and have it checked out as soon as possible.<\/p>\n\n\n\n

    On a side note, if you see a check engine light error, it may also mean your catalytic converter has been stolen. Look for these signs<\/a> if you suspect catalytic converter theft.<\/p>\n\n\n\n

    Unburned fuel in the exhaust system<\/h3>\n\n\n\n

    Another common cause of converter failure is unburned fuel in the exhaust system. This can happen if the engine is running<\/a> too lean (not enough fuel) or if the spark plugs are fouled, causing the engine to misfire.<\/p>\n\n\n\n

    Unburned fuel can damage the catalyst material, causing it to lose its ability to convert emissions efficiently. <\/p>\n\n\n\n

    In addition, unburned fuel can also cause the converter to overheat and damage the honeycomb structure.<\/p>\n\n\n\n

    Oil or antifreeze entering the exhaust system<\/h3>\n\n\n\n

    If oil or antifreeze enters the exhaust system, it can coat the catalyst material and prevent it from working properly.<\/p>\n\n\n\n

    Additionally, oil or antifreeze build-up can also clog the air passage to the honeycomb structure inside the converter.<\/p>\n\n\n\n

    It can further lead to two significant problems:<\/p>\n\n\n\n

    1. The carbon deposits will stop the catalytic converter from doing its job<\/li>
    2. Restricting the exhaust flow will increase backpressure<\/li><\/ol>\n\n\n\n

      These problems can cause the converter to overheat and the excess backpressure can cause internal engine damage which would be very costly to repair.<\/p>\n\n\n\n

      Low coolant level<\/h3>\n\n\n\n

      Coolant is used to keep the engine from overheating and it should be properly maintained at all times.<\/p>\n\n\n\n

      If the coolant level gets too low, it can cause the engine to overheat and damage the catalytic converter.<\/p>\n\n\n\n

      In addition, low coolant levels can also lead to engine damage, so it’s important to keep an eye on the coolant level and top it off as needed.<\/p>\n\n\n\n

      Bad spark plugs or spark plug wires<\/h3>\n\n\n\n

      While it’s not very common, bad spark plugs or spark plug wires can cause the engine to misfire, which can damage the catalytic converter.<\/p>\n\n\n\n

      Misfiring can also cause unburned fuel to enter the exhaust system, which we mentioned earlier is one of the most common causes of converter failure.<\/p>\n\n\n\n

      If you suspect that your spark plugs or wires are bad, it’s important to have them replaced as soon as possible.<\/p>\n\n\n\n

      Damage to the honeycomb structure<\/h3>\n\n\n\n

      The honeycomb structure inside the catalytic converter can be damaged by physical impact or by excessive vibration.<\/p>\n\n\n\n

      Additionally, the structure can also become damaged over time due to the high temperatures and harsh chemicals inside the converter.<\/p>\n\n\n\n

      Once the honeycomb structure is damaged, it can’t be repaired and the entire converter will need to be replaced which can be costly.<\/p>\n\n\n\n

      Short trips<\/h3>\n\n\n\n

      If you frequently drive short distances, your catalytic converter may not have enough time to reach its operating temperature.<\/p>\n\n\n\n

      If you look at how a catalytic converter works, you’d notice that it needs to be heated up to its operating temperature in order to work properly.<\/p>\n\n\n\n

      If it’s not heated up, the unburned fuel and emissions will build up inside the converter and damage it. Over time, this can cause the converter to fail and will need to be replaced.<\/p>\n\n\n\n

      So, if you frequently drive short distances, it’s important to take your car on a long drive every once in a while to give the converter a chance to reach its operating temperature.<\/p>\n\n\n\n

      Road or structural damage<\/h3>\n\n\n\n

      If you hit a large pothole or other road hazards, it can damage the undercarriage of your car which can lead to catalytic converter damage.<\/p>\n\n\n\n

      Additionally, if you drive over uneven roads too fast, it can also cause the converter to break loose and be damaged.<\/p>\n\n\n\n

      While it’s not very common, physical damage to the converter can occur and it’s important to be aware of it.<\/p>\n\n\n

      \n
      \"Road<\/figure><\/div>\n\n\n

      Fuel additives<\/h3>\n\n\n\n

      Using fuel additives can sometimes reduce the effectiveness of a catalytic converter.<\/p>\n\n\n\n

      Certain types of fuel additives can coat the catalyst material and prevent it from working properly.<\/p>\n\n\n\n

      In addition, some fuel additives can also clog the honeycomb structure inside the converter and cause damage.<\/p>\n\n\n\n

      If you’re using fuel additives, be sure to read the label carefully and only use the fuel additives that are specially designed to be used with catalytic converters.<\/p>\n\n\n\n

      Exhaust leaks<\/h3>\n\n\n\n

      An exhaust leak is when exhaust gases that are made inside the engine’s combustion chamber escape from the car through a leak in the exhaust system.<\/p>\n\n\n\n

      Exhaust leaks can allow more hot air, unburned fuel, and emissions to enter the catalytic converter which can damage it.<\/p>\n\n\n\n

      In addition, exhaust leaks can also cause the converter to overheat and fail.<\/p>\n\n\n\n

      If you suspect that you have an exhaust leak, it’s important to have it repaired as soon as possible.<\/p>\n\n\n\n

      Faulty valve seals and piston rings<\/h3>\n\n\n\n

      Faulty valve seals and piston rings can cause oil and other fluids to enter the combustion chamber and be burned along with the fuel.<\/p>\n\n\n\n

      This can lead to the formation of sludge and deposits inside the engine which can eventually make their way into the catalytic converter.<\/p>\n\n\n\n

      Once these deposits build up inside the converter, they can clog and damage the honeycomb structure and cause it to fail.<\/p>\n\n\n\n

      Signs and Symptoms Of A Bad Catalytic Converter<\/h2>\n\n\n\n

      While it’s important to understand what causes the catalytic converter to go bad, you should also be aware of the signs and symptoms that indicate that your converter is failing.<\/p>\n\n\n\n

      The most common sign of a bad catalytic converter is an increase in exhaust fumes and a decrease in engine performance. Also, if you notice that your engine is misfiring, stalling, or has a loss of power, it’s possible that your converter is to blame.<\/strong><\/p>\n\n\n\n

      The most common signs and symptoms of a bad catalytic converter are:<\/p>\n\n\n\n