Does a Diesel Engine Have a Catalytic Converter? [Explained]

Governments have set regulations and laws for automobiles. One of these regulations is installing a Catalytic Converter in a vehicle’s exhaust system. Car manufacturers strictly observe this law.

Diesel engines have a Catalytic Converter, but this functions differently from cars with a gas engines. This is because Diesel engines use compression for fuel combustion compared to gas engines which use a spark. 

How Do Catalytic Converters work on Diesel Engines?

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Along with acting as a filter for the car’s exhaust, Catalytic Converters reconstruct the elements of exhaust fumes. 

It does this in four phases:

  • Exhaust Gas Recirculation
  • Diesel Particulate Filter
  • Diesel Oxidation Catalyst
  • Selective Catalytic Reduction

Types of Catalytic Converter

Oxidation Catalyst (OC) 

CO and HC are transformed into CO2 and H2O, which is not harmful to the environment. 

Three-way catalyst (TWC)

Along with doing the same function as an OC, it converts Nitrogen Oxide into non-harmful substances. 


 It is a combination of the two types above. It is said that this type of catalytic converter is the most efficient in reducing air pollution. 

Catalytic Converter Maintenance and Upkeep

There are a couple of steps to maintain a Diesel engine Catalytic Converter’s optimal condition. One of which is using high-grade fuel, preferably recommended by the car manual. This is to prevent lead poisoning. 

Another one is using manufacturer-approved additives and lubricants. Low-quality substances and additives may create converter-damaging byproducts. 

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Catalytic Converters require high temperatures to operate. That is why, when driving, it is preferred that you stay clear of deep puddles.

Once a Converter at high temperatures comes in contact with water, the temperature may drop rapidly. It may cause it to break.

Of course, the best upkeep is still prevention. Every time you get your vehicle serviced, check the converter for any abnormalities. Odd sounds or chinks may be a sign to replace the converter.

Why Should Catalytic Converters be used?

Converters are essential for alleviating the formation of hazardous smog. This is especially present in vehicles that operate on ICE Engines.

There are different types of converters, such as 2-way or 3-way connection catalytic converters. 

Ultimately, they serve the same purpose, to convert carbon monoxide to carbon dioxide. Any step that can prevent our atmosphere from being more polluted should be done.

Frequently Asked Questions

How long do Catalytic Converters last?

A Catalytic Converter can survive for up to 10 years for Diesel engines. That’s up to 100,000 miles. It also depends on how often the vehicles are serviced. 

The converter’s lifespan also depends on the length of the car’s trips. A vehicle that travels long distances at a time will have a longer converter lifespan than one with short trips.

Catalytic Converters are very costly to replace, so it is vital to observe proper maintenance. 

What are the signs of defective Catalytic Converters?

There are a couple of signs to spot a faulty Catalytic Converter. These signs include carbon deposit build-up, physical damage, and infection. 

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The engine will show symptoms such as meager engine performance, acceleration problems, putrid smells, and vehicle overheating. Modern converters have a signal light to inform users about these. 

What is the price of Catalytic Converters?

There is a very wide array of Catalytic Converters. Each of them with a different type and quality level. The price also depends on where you purchase it from. 

It is important to know that the market for Catalytic Converters for Diesel engines is quite prominent. To give a ballpark figure, prices range from $4 to $500.

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