7 Symptoms of Catalytic Converter failure | Causes for failure

Catalytic Converter is the most important part of a restriction for air pollution which is caused by cars. It is located between the exhaust system and the muffler. It is shortly named as “Cat-Con.” Pollutants like Unburnt gases and oxides of nitrogen are actually harmful to the environment and human system. These pollutants are converted into harmless gases by catalytic reaction.

• Working of a Catalytic Converter

Catalytic conversion occurs in cat-con. It consists of the honeycomb structure made up of precious metals like platinum, rhodium, and palladium. These metal plates convert the harmful gases ( unburnt hydrocarbons, carbon monoxide and nitrogen oxides) into harmless gases such as oxygen, water, carbon dioxide, and nitrogen elements. Catalytic Converter can do smooth work and stands out at the highest temperatures.

• Catalytic Converter failure Causes

Generally ‘cat’ is failed by contamination, clogging, overheating or physically damaged. If these reasons appeared then you can easily notice the engine’s malfunction. Choked up or clogged cat-con won’t be capable for a smooth transfer of exhaust gases. This affects the engine performance. In a worse scenario, it is completely blocked and develop the backpressure on the engine working.

  • Exhaust gas if it contains lead, the metal catalysts are going to be destroyed. The honeycomb structure is affected. This happens rarely.
  • If coolant and oil are burnt in the combustion chamber due to blown head gasket, bad valve seals, or worn piston rings then there is a possibility for contamination and clogging with carbon soot.
  • If a lot of unburnt gases are produced due to engine misfiring then it will be the reason for cat-con overheating. Misfiring Spark plug or leaky exhaust valve are the reasons for passing the unburnt gases. The oxygen sensor’s failure also causes overheating.
  • Another failure is a damaged cat – con. Any accidental impact or physical damage happens on it then surely performance will decrease.

The above reasons are responsible for the failure of cat – con. It affects the engine. Generally, Exhaust gas flow is restricted so the engine sucks less air and could backfire, It starts malfunctioning in running condition.

• Symptoms –

Some symptoms are there with which you could easily notice whether cat – con is failed or not.

1 – Affected fuel economy

Engine performance parameters like fuel economy, air-fuel mixture, acceleration are affected due to clogged cat-con. Air is less injected than required in the system which results in more fuel to be burnt. If you find a lower fuel economy, you can predict the clogging of the cat-con.

2 – Acceleration problem

The engine required more power to be produced while the acceleration is taking place at top speed therefore Exhaust should be smooth enough to pass more and more gases. Though you require more power, If cat con is clogged then you will definitely suffer from acceleration.

3 – Check engine light is flashed

In modern cars, there is an oxygen sensor which manages to monetize the exhaust gases. If it fails or cat con gets failed then probably the check engine light is illuminated because of various cat-con failure reasons. There are a lot of reasons to flash the check engine light but if you find the trouble code P0420 or P0430 on the scanning tool, there is a problem with the cat-con.

4 – Exhaust Smoke Colour

Clogged cat-con causes more dark smoke due to trapped soot particles. More fuel is required to run the engine which causes unburnt fuel gases to exhaust. It will affect the smoke which consists of more carbon particles.

5 – Sulphur Smell

If cat con gets failed then exhaust gases with more sulphur which could not be converted or trapped, then you have to suffer from a smell of the hydrogen sulphide from the exhaust which is similar like rotten eggs smell. Cat con converts the sulphur into sulphur dioxide when it works in good condition.

6 – Exhaust System Noise

Exhaust system noise which could be easily noticed while the sudden acceleration is made by the driver. The honeycomb structure is broken due to excessive heat or damage inside the cat-con then such noise will come. This noise is like rattling noise.

7 – Emission Test failure

Emission tests are required to measure exhaust gas quantity. There is a limitation for each pollutant gas. If it is crossed in emission test. Your car definitely has a problem with cat-con.

Some of those symptoms can also be caused by other parts of the emissions system, so it’s important for a mechanic to diagnose when it’s time to replace your catalytic converter.

• Precautions –

  • If above symptoms are there, Immediately you can take your car to the service centre.
  • the catalytic converter has a lifetime efficiency but if adverse happens then please replace it.
  • At some service centers. They break the honeycomb structure with hard metal and further they sell precious metals ( palladium, platinum and rhodium ). If any mechanic tells you about breaking that cat-con then be aware because it has a greater value.

• Replacement Cost –

Around $600 – $1000
( It will vary according to model )

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