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Does a Diesel Engine Have a Catalytic Converter?

Does Diesel Engine Have Catalytic Converter

Diesel engines have their own version of a catalytic converter. In fact, nearly all diesel engines since 1990 have catalytic converters. You can find them between the engine and muffler like you would on any vehicle with an internal combustion engine.

A catalytic converter is responsible for reducing the amount of emissions a vehicle puts out. The catalytic converter was introduced on gasoline powered cars in 1970 before making their way onto most vehicles with a diesel engine by 1990.

Just like gasoline powered engines, diesel engines are required to meet non-toxic emissions standards. That’s why almost all diesel engines produced after 2000 have a catalytic converter.

How a Catalytic Converter Works

A catalytic converter changes harmful gases into less harmful emissions.

Through a chemical reaction, catalytic converters change the harmful substances in exhaust gases like carbon monoxide, nitric oxide, nitrogen dioxide and hydrocarbons into less harmful substances like carbon dioxide and water vapor. The interior of a cat often has a honeycomb structure onto which a coting is applied that contains a catalyst (a substance that creates a chemical reaction).

In a catalytic converter the catalyst changes the chemical structure of harmful gases so that they are less harmful. Precious metals like palladium, rhodium and platinum are used as the catalyst. These precious metals are worth some money, which is what makes catalytic converters a target for thieves.

How a Catalytic Converter in a Diesel Engine Works

The major difference between a catalytic converter from a gasoline engine and one from a diesel-powered engine is in the metals used to create a catalytic reaction.

The major difference between a catalytic converter from a gasoline engine and one from a diesel-powered engine is in the metals used to create a catalytic reaction.

In a diesel engine’s catalytic converter, the interior of the metal casing has two ceramic blocks with thousands of micro-cellular units. The ceramic blocks are coated with precious metals like palladium and platinum to create the catalyst.

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These metals heat the ceramic blocks to catalyze the chemical and turn them into less harmful emissions. The catalytic converters from diesel engines don’t use rhodium. Diesel engines also come with a particulate filter to strain out any particular matter from a diesel engine which gasoline powered engines don’t have.

A Catalytic Converter in a Diesel Engine Lasts as Long as Any Other

A catalytic converter for a diesel engine can last up to 100,000 miles, or about ten years which is the same lifespan as a gasoline powered engine. But getting it to last that long depends on your driving behavior. Short fifteen-minute trips to the supermarket will wear out a diesel’s catalytic converter fast.

That’s because short trips don’t give the catalytic converter enough time to reach operational temperature to catalyze compounds. The more the diesel engine gets turned on and off, the more wear and tear is done to the cat. But long cross-country trips will prolong the life of a catalytic converter attached to a diesel engine.

Signs Your Diesel Catalytic Converter is Failing

The way to tell if your diesel catalytic converter is failing is the same as with any other catalytic converter – you’ll get a check engine light. Driving with a failing catalytic converter is not recommended for either a gasoline or diesel-powered engine. Doing so will lead to even more serious issues, like:

  • Slow engine performance,
  • Reduced acceleration,
  • The smell of rotten eggs,
  • Particularly dark exhaust smoke,
  • Extreme heat coming from under the vehicle.

All these are signs of a clogged catalytic converter can lead to complete engine failure. While a catalytic converter is expensive to replace. Once it has failed, it’s recommended that you change it as quickly as possible.

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Diesel Catalytic Converters Aren’t Stolen Often

Diesel catalytic converters aren't stollen nearly as often as gasoline cats because they're not worth as much.

Unlike gasoline catalytic converters, diesel catalytic converters aren’t home to that many precious metals. For one, they lack the rhodium that gasoline catalytic converters have which makes diesel catalytic converters less desirable at junkyards and scrap yards where they get converted into cold hard cash.

While that doesn’t necessarily make diesel catalytic converters value-less to thieves. For the most part, if you drive a diesel-powered truck. You can sleep easy at night with your truck parked out on the street.