Do Diesel Engines Have Catalytic Converters?

Undoubtedly, there are several differences between gasoline and diesel-powered engines. However, they also have a couple of similarities. The big question is – Do diesel engines have catalytic converters?

The catalytic converter plays a very vital role in a vehicle’s emission system. No wonder the Environmental Protection Agency (EPA) is strict about its use in automobiles. However, most vehicle enthusiasts associate the cat-con with gasoline-powered vehicles.

This article probes into the use of catalytic converters across the automotive industry, especially in diesel-powered engines, in order to unveil whether they are available in them or not. The subsequent sections unravel all you need to know about the converter, including its problems and solutions.

do ford diesels have catalytic converters

Read Also: Signs and Symptoms of a Bad Catalytic Converter

Do Diesel Engines Have Catalytic Converters?

Diesel engines are also built with catalytic converters, just like their gasoline-powered counterparts. This is because the emissions system requires the catalysts in the converter to neutralize the toxic pollutants before they are channeled out via the exhaust pipes.

However, if you’re contemplating “Diesel catalytic converter vs. gas cat converter,” the converters in diesel engines are built slightly differently from the regular ones used on gasoline-powered engines.

Diesel engines possess a two-way or three-way cat converter design, having a DOC, as well as an SCR reduction, respectively.

Usually, the diesel oxidization catalyst (DOC) and selective catalytic reduction (SCR) are the two main stages of diesel engine emissions that trigger the chemical reactions which help to detoxify harmful pollutants before they are released into the air.

If you’re wondering, “Do diesel cars have catalytic converters and DPF?” Other stages of diesel engine emissions include the EGR and DPF. However, these are the first two stages, while the DOC and SCR are the last two stages where the actual emissions neutralization work lies in the system.

Common Problems of Diesel Engine Catalytic Converters

Like every other catalytic converter, diesel engine converters are not problem-free. They are susceptible to a couple of challenges that you would need to deliberately prevent from occurring or fix after their occurrence. Some of the common problems of diesel engine catalytic converters are:


A faulty cylinder head will create an opportunity for engine coolant to escape out of its place into other areas, including the catalytic converter. This can automatically affect the easy passage of exhaust gases in the converter.

Carbon deposits blockage

The catalytic converter is exposed to carbon build-up over time, which tends to block the system. When the converter becomes blocked, it will not be able to perform its function as expected.

Restriction of exhaust gas free flow

A vehicle’s engine requires a constant supply of air for efficient performance. If the free flow of gas from the exhaust system is hindered, it will automatically affect the supply of air, which further affects the engine ultimately. This is a common challenge with the cat converter.


Faulty Glow plugs and a leaky exhaust valve are two culprits of inadequate burning of diesel fuel. When this occurs, overheating is imminent because the unburned fuel may be channeled to the converter to burn properly. This will certainly disrupt the converter’s function.

Physical damage

The catalytic converter is mounted underneath a vehicle aligning with the engine and the muffler. Unfortunately, this exposes the component to mechanical operations that can result in its wear, tear, or damage over time.

The component is also vulnerable to weather conditions, as well as elements on the road that come in contact with the component and damage it within a short time. The vibration from driving on rough roads is yet another damaging factor.

Read Also: How to Unclog a Catalytic Converter? All That You Need To Know

How Do You Fix Diesel Engine Catalytic Converters Problems?

Fixing a diesel engine cat converter problem will be easy if you’re able to identify the actual cause of the problem. That’s why it would be best to inspect or diagnose the component and carefully ascertain the exact issue. However, the following recommendations will be able to fix a bad diesel engine catalytic converter.

Unclog the converter

Firstly, if carbon build-up is responsible for the catalytic converter issue, ensure to unclog it using a degreaser and hot water solution. Once you have the solution ready, soak the converter in it for about one hour.

After that, get a pressure washer and set it down to low. Then, use the water to rinse the component carefully and allow it to drain out the water and dry up properly. After that, reinstall the component. Also, note that you can use a diesel catalytic converter cleaner to get the job done as well.

Replace faulty related parts

If a faulty oxygen sensor, head gasket, etc., is responsible for the malfunctions that led to the problem with the catalytic converter, ensure to replace the exact component. However, carefully diagnose the problem to identify the actual faulty component before a replacement.

Replace the catalytic converter

Finally, if every other attempt seems abortive and the catalytic converter is still incapacitated, go ahead and replace the component. No doubt, replacing a cat converter can be quite expensive; however, it is better to resolve a problem at an early stage before it escalates.

Can Diesel Engines Run Without a Catalytic Converter?

Of course, a diesel engine can run without a catalytic converter because the component does not play a role in the locomotion process of a vehicle. However, driving without the converter will alter the car’s overall engine performance and produce unpleasant noise while on the road.

Besides the impact of the absence of a catalytic converter, when the component is missing in a vehicle, the vehicle will likely fail the emissions test. This is because it is entirely illegal to drive without a cat converter, and the emissions from the vehicle’s exhaust pipes will pose a threat to the atmosphere.

Therefore, the Environmental Protection Agency is responsible for ensuring that every vehicle manufactured after 1975 is fitted with one or more catalytic converters. This is strictly in line with the 1970 Clean Air Act.

So, inasmuch as your diesel engine can run without the presence of a catalytic converter, do not risk eliminating the component from your car. If you do so, you stand a risk of being slammed with a fine or failing your next emissions test.

What’s the point of taking the component off when you’re just fine with it on your car? The component does not only serve as an advantage in helping you scale through an emissions test, but it also protects you and everyone else from toxic exhaust pollutants.

If you were wondering, “Do modern diesel have catalytic converters?” Of course, they do! Remember, every vehicle after 1975 has been subject to the 1970 Clean Air Act.

diesel catalytic converter vs gas

Read Also: How to use Catalytic Converter Cleaner?


Do diesel catalytic converters get stolen?

Of course! Diesel catalytic converters also get stolen, just like those in gasoline-powered vehicles. The reasons for the ordeal in both cases are pretty much similar – the cat converters in gasoline and diesel engines can be turned into a few bucks.

So, it is obvious that converter vandals have no business trying to separate between cars with petrol engines and those with diesel engines. They are all prospective victims if you’re asking – Do thieves steal diesel engine cat converters? So, you must guard your car jealously.

Are diesel engine catalytic converters worth anything?

The diesel catalytic converter scrap value is worth some cool cash in the scrap metal market. However, they are not as expensive as gas engine catalytic converters. This is because diesel fuel comes cleaner than regular gasoline; hence, the converter only requires minimal catalysts.

In other words, the precious metals in the gasoline engine catalytic converters are more than their diesel engine cat converters counterparts. In any case, the diesel cat converters still rake in some money when sold as scrap.

How much is a diesel catalytic converter worth?

A scrap diesel catalytic converter is worth as low as $18 and as much as $625. However, the worth of the converter depends on the vehicle’s make and model. While some diesel engine cat converters may fall within this price range, others may be slightly more.

Whatever the case may be, an old converter still has some economic value. You could sell it to a scrap metal dealer or junkyard near you to get a few dollars into your pocket.

What year did diesel start using catalytic converters?

When did they start putting catalytic converters on diesel? Diesel engines started using catalytic converters around the 1990s. Before then, the components were common with gas engines because of the extent of pollutants emitted via the exhaust pipes of gasoline-powered vehicles.

Typically, the deterioration of the air quality in several cities around the 1940s – 50s necessitated the introduction of catalytic converters in the mid-1970s. This became the solution to the air pollution problem.

What cars don’t have catalytic converters?

All-electric cars are the only cars without catalytic converters. Instead, they are built with rechargeable batteries, which help to power the EVs without any emission effects. Other vehicles like hybrid cars, regular gasoline cars, and diesel-powered vehicles are fitted with cat converters.

The reason is pretty simple – the emissions from these vehicles have negative impacts on the air quality in the atmosphere. Therefore, the converters help detoxify the pollutants before the exhaust pipes release the emissions.

Do thieves target diesel catalytic converters?

Of course, diesel catalytic converters are also targeted by cat converter thieves; if you’re asking, “Do thieves steal diesel catalytic converters?” This is because they contain some precious metals in their makeup. So whether you drive a gasoline or diesel-powered car, you are sure to protect your converter from folks who won’t miss a chance to pull it off.

Catalytic converter theft has not ceased from rising by the day. According to a report from the NICB – National Insurance Crime Bureau, vehicle owners made claims for about 3,389 converter thefts in 2019 and another whopping 14,433 cat converter thefts in 2020.

Where is the catalytic converter on a diesel truck?

A diesel truck’s catalytic converter is between the muffler and the engine underneath the vehicle. The component is fitted as a subset of the exhaust system. Most vehicles have their cat converters positioned around the same area.

However, while some cars are manufactured with one catalytic converter, others have two or more, depending on the vehicle’s make and model. Unfortunately, the more the number of converters, the more you need to guard against theft.

How much is a Cummins catalytic converter worth?

A Dodge Cummins 6.7 catalytic converter is worth between $60 and $600. If you drive any of the following vehicles; Ram 2500, RAM 3500, 4500, 3500 heavy-duty truck, and 5500 Chassis Cab, ensure to protect their converters from thieves.

Meanwhile, you can sell the old cat converter for some cash inflow when you get a replacement. However, ensure to verify the scrap catalytic converter price online before contacting a junkyard or scrap metal dealer around your neighborhood.

Does Ford Diesel have a catalytic converter?

Yes! Ford diesel-powered vehicles are built with catalytic converters. The component is present in diesel engines that are manufactured around the 1990s till date. Typically, the converters are essential for neutralizing the toxic pollutants in the vehicles’ exhaust systems.

If you drive a Ford F-150 with a Power Stroke diesel engine, the cat converter is the component responsible for managing the emissions system properly, preventing the release of toxins. Without the component, driving the F-150 would have been illegal in the United States.

Do heavy-duty trucks have catalytic converters?

Of course, heavy-duty trucks are built with catalytic converters. The component is necessary to help curb the challenges of hazardous emissions. The cat converter is relevant in virtually all vehicles except electric cars.

Converter vandals also target the cat converters in heavy-duty trucks because they are built with some precious metals like most cars. However, some trucks have a relatively cheaper cat-con, which does not call the attention of converter theft specialists.

Final Words

This article has told the truth about the availability of catalytic converters in diesel engines. In addition, some of the common problems of the component have been addressed, as well as the recommended solutions.

So, anyone contemplating, “Do diesel engines have catalytic converters?” kindly recommend this post to them. Meanwhile, if you’re currently experiencing any of the challenges unveiled above, ensure to implement the solutions provided in this article.

Lastly, always be conscious about your vehicle whenever you’re away from home, especially at night. Cat converter thieves are virtually everywhere. You don’t want to be their victim.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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