Do Diesel Trucks Have Catalytic Converters?

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Catalytic converters are used to detoxify excessive emissions from diesel engines, and they have become an integral part of diesel engines since 1990. But what do catalytic converters do, and do diesel trucks have them? 

Catalytic converters reduce the toxicity of emissions before releasing them into the atmosphere. Most modern diesel trucks have them, and they also increase fuel efficiency. Contamination, clogging, and overheating are common problems, but there’s ways to solve them without resorting to replacement.

Let’s discuss how a catalytic converter works, what problems you may face with it, and useful tips to fix these problems. 

What Does a Catalytic Converter Do?

Catalytic converters

A catalytic converter helps detoxify vehicle emissions and has been strictly recommended by the Environmental Protection Agency (EPA). It has been popular in truck manufacturing, especially in diesel-based truck engines, since 1990. 

Catalytic converters have metal-coated ceramic blocks that usually contain the metals platinum, rhodium, and palladium. They convert the emission of carbon monoxide into diatomic nitrogen and water by infusing oxygen into the exhaust fumes. This reduces about 90% of the harmful impacts of these emissions. 

This is necessary because carbon monoxide is toxic. Even small amounts produced by car engines can severely affect air quality. 

Of course, you can run your vehicle without a catalytic converter because it has no part in the locomotion process of the engine. But, running your truck without it may affect its performance and reduce the vehicle’s fuel efficiency.  

Besides, you won’t be able to run your truck legally without passing an emissions test if you don’t have the converter. This is why many countries are phasing out vehicles without catalytic converters.

Do Diesel Trucks Have Catalytic Converters?

Most modern diesel pickup trucks have catalytic converters as truck manufacturing is evolving to become more eco-friendly. This helps neutralize the toxic pollutants and the overall impact of larger vehicles on the environment. 

A two-way catalytic converter is commonly used in trucks, but some also use three-way catalytic converters for selective catalytic reduction (SCR) to remove specific chemical compounds.  

In this process, the diesel oxidation catalyst (DOC) converts carbon monoxide into carbon and water. Then the diesel particulate filter (DPF) converts other particulate matter into less harmful substances. SCR breaks down nitrogen oxides into nitrogen and oxygen gas.

Since diesel trucks produce higher percentages of carbon monoxide, it’s essential that they have more advanced catalytic converters. However, the catalytic converters on diesel trucks are often more advanced and work differently from those in gas-powered vehicles. 

Where is the Catalytic Converter Located on a Diesel Truck?

The catalytic converter is usually placed under the truck, near the engine, between the exhaust manifold and expansion box. It will also be close to the muffler and is usually fitted as a subset of the exhaust system. 

However, the location of your truck’s catalytic converter depends on where you live and what type of converter you are using. Exhaust gas recirculation (EGR) systems and DPF are commonly used in the USA, and the catalytic converter is typically near the exhaust stream. 

Europeans largely use SCR, which is put with a decomposition tube near the exhaust stream.   

The location of the converter has a considerable effect on how long it lasts. A converter placed away from the exhaust will require a longer connection pipe, which is more prone to damage and leakages.

Unfortunately, catalytic converters have always been an attractive target for thieves because of the platinum and other metals they contain. So, most truck owners get it placed on one side of the truck near the engine, and they spend a little more money to get a longer connection pipe to connect it with the exhaust. 

This way, it becomes difficult to remove the converter, and thieves are discouraged. Some truck owners take it one step further and will remove the catalytic converter when parking their trucks unattended. 

What Are the Common Problems of Diesel Engine Catalytic Converters?

Catalytic Converted with Oxygen Sensor Under Car

Like gasoline engine converters, diesel engine catalytic converters aren’t problem-free. Bad engine performance, reduced acceleration, emission of dark smoke, and excessive heat under the truck are some of the prominent signs of a bad catalytic converter. 

This will lead to common challenges you may face with diesel engine catalytic converters. These include converter contamination, carbon deposit clogging, air blockage, physical converter damage, and overheating. 

Let’s discuss each of them in detail:   

Converter Contamination

Contaminants like oil and coolants may penetrate the converter as a result of a faulty cylinder head. This will contaminate the converter, releasing toxic pollutants into the atmosphere. 

These contaminants can also leak into the engine and cause mild to severe engine damage.  

When the converter is contaminated, it gives off a sulfur or “rotten egg” smell. 

Clogging With Carbon Deposits

Carbon deposits may build up inside the converter over time and may result in converter clogging. A blocked converter won’t take in exhaust fumes, resulting in toxic exhaust emissions. 

A clogged catalytic converter will also cause engine suffocation, which may result in poor acceleration. You may also notice that it becomes difficult to start the engine.

Air Blockage

Blocked air in the system will also affect engine functioning since the engine requires a constant supply of air to work effectively. While this is a minor problem, it may indicate something’s wrong with your truck’s exhaust system. 

A Damaged Converter

Since the catalytic converter is placed under the vehicle, it’s usually exposed to physical damage as a result of bad weather and rough road conditions. 

This will wear the converter over time, causing it to malfunction. You can prevent this damage by doing regular maintenance of the converter and driving carefully over rough roads. 

Catalytic Converter Overheating

A catalytic converter may overheat when excessive diesel is burnt in the engine. The unburned fuel gets into the converter as a result of a leaking exhaust pipe and faulty spark plugs. Overloading your truck can also place more pressure on the engine, which can also cause overheating. 

Luckily, modern diesel trucks have inbuilt sensor systems to detect problems in the engine and catalytic converters. But, if you are unable to track the problem, take your truck to a mechanic for inspection. 

Unfortunately, most catalytic converters are difficult to repair, and replacements are expensive. 

How Do You Repair a Faulty Catalytic Converter in a Diesel Truck?

You can fix the catalytic converter without replacing it if the problem isn’t too bad. Cleaning the converter, doing “the Italian tune-up,” adding fuel additives, and fixing exhaust problems are some of the most common fixes. 

However, the ideal solution for your bad catalytic converter may vary depending on the actual problem.

Let’s discuss each solution in detail:

Clean The Catalytic Converter

Not all bad converters are hard to fix, and you can simply clean them if there’s a minor problem. Follow these steps to clean a catalytic converter: 

  1. Obtain catalytic converter cleaner. 
  2. Insert the catalytic converter cleaner into the fuel. 
  3. Start the truck engine and drive.
  4. Check the instructions on the cleaner label for how long you should drive, although the recommended time is around two hours. 
  5. You can also remove the converter and clean it with oil if you don’t see ideal results. 

Remember, cleaning the converter won’t resolve any mechanical problems and can only help remove debris, dust, and clogging. 

Do “The Italian Tune-up”

The “Italian Tune-up” helps burn clogging deposits and contaminants by running the truck harder than usual for a few miles. The most efficient heat-up temperature for the catalytic converters is between 800 to 1832 F. 

This will heat up the converter and burn-off dirt and fuel deposits. However, avoid doing this if you aren’t an experienced driver and preferably have a mechanic do the tune-up for you. 

Fix Exhaust Problems

Exhaust problems often cause the catalytic converter to malfunction as leaks in them cause converter clogging, contamination, and malfunctioning. If you notice a louder-than-usual exhaust or smoke and fuel coming out of the exhaust, have it checked immediately. 

Check For Other Engine Problems

Sometimes, there may be nothing wrong with the catalytic converter, but engine problems like fuel trim, coolant burning, and an engine misfire may indirectly affect the converter. Fixing these engine problems will reduce damage to the catalytic converter. 

Switch to High-Octane Fuel

It’s worth switching to the best quality fuel rather than causing damage to the converter. Low-quality fuel may be cheaper, but it often contains contaminants that will damage the catalytic converter over time. 

If the converter is badly damaged, you should get professional help. You may need to replace the catalytic converter if it’s irreparable, so be mentally prepared for the cost!