Semi-truck catalytic converter location

Semi-trucks can be some of the biggest culprits for carbon emission, thanks to their internal combustion engines that are more fuel-consuming.

As such you want to provide proper maintenance to your catalytic converter to ensure that it remains effective at converting the harmful compounds from your engine’s emissions to steam and other safe gasses.

You might be wondering; where is the location of a catalytic converter in a semi-truck?

The semi-truck catalytic converter location is usually on the exhaust pipe, between the engine and the muffler, just like in any other type of vehicle. The precise part where this component is found normally has a beaded shape or honeycomb.

Does Catalytic Converter Location Differ in Semi-Trucks? 

It depends on the type of exhaust system on the semi-truck. These trucks come with either a horizontal exhaust system or a vertical exhaust system.

In semi-trucks with a horizontal exhaust system, the exhaust pipe runs horizontally along the underside of the truck. Meaning their catalytic converter location is underneath them. 

In semi-trucks with a vertical exhaust system, on the other hand, the exhaust pipe is visible, running vertically upward along the side of the truck’s cabin.

This is usually just behind the driver’s door or the passenger’s door. Meaning their catalytic converter location is just beside the cabin’s exterior.

Are Semi-Truck Catalytic Converters Different Than Cats on Regular Cars?

Yes, semi-truck catalytic converters are certainly different from cats on regular cars. That’s because trucks have diesel engines.

And there’s a good reason for that— theese engines produce bigger greenhouse gas emissions that are better handled by larger catalytic converters alongside the DPF and Adblue

Types of Semi Truck Catalytic Converters

Diesel Oxidation Catalyst

Of course, these catalytic converters are specially designed for diesel engines to reduce pollution such as Carbon Monoxide (CO2), Hydrocarbons, and Particulate Matter, helping the main Diesel Particulate Filter (DPF) and Adblue.

Are Semi Truck Catalytic Converters More Expensive Than Regular Ones?

Diesel catalytic converters are very different than converters used on gasoline (petrol engines) because of the substances that come out of the exhaust on each engine type.

Diesel engines run with excess air. Because of that, they emit a small number of hydrocarbons or carbon monoxide. On the other hand, diesel engines will emit large amounts of nitrogen oxides and particulate matter.

As a result, diesel engines will use catalytic converters and particulate filters that focus on capturing that particulate matter and nitrogen oxides (NOx).

Because diesel is cleaner than gasoline, catalytic converters used in diesel engines are less expensive than their petrol counterparts.

Catalytic converters for diesel engines are not as valuable as those for gasoline engines. Because these catalytic converters are made from cheaper materials, and the precious metals within them are less dense, so they are less expensive.

Do Thieves Steal Semi Truck Catalytic Converters as Well?

Thieves will steal all types of catalytic converters regardless. That’s because these commodities are pricey and can fetch pretty good money, thanks to what’s inside; rhodium, platinum, and palladium.

These are among the most precious metals out there. Matter of fact, they are considered the most expensive scrap.

However, thieves will not target catalytic converters on trucks more than any other type of vehicle since truck converters are less valuable.

It can cost up to $3000 to replace a stolen catalytic converter. Taking that into account, it’s important to do a few things that will help keep thieves away from your converter. 

One of them is to invest in a catalytic converter metal cage. This protective accessory will protect your converter by enclosing it with a material that is hard to cut through.

And as you already know, thieves do not tend to waste time trying to get around obstacles. If you can’t buy this accessory due to one reason or another, always avoid parking your vehicle away from people and/or CCTV cameras. 

Can a Vehicle Move Without a Catalytic Converter?

It can, technically. Unfortunately, this isn’t a sustainable option as you’ll face lots of problems e.g a loud engine noise, causing cops to be always after you with hefty pollution fines.

Secondly, you’ll experience rough driving and acceleration as the forceful exhaust push will result in jarring and other issues that lead to these problems.

Thirdly, your vehicle will not pass the next inspection, meaning it won’t be authorized to be on the road. In most countries, a vehicle inspection is a mandatory yearly process to which all vehicles are subjected.


Semi-trucks, mostly newer ones, come with a specific diesel catalytic converter that helps purify the substances that come out of the engine through the exhaust system.

Characterized by a beaded shape or honeycomb, this part is located in the exhaust system between the engine and the muffler. Just like in small cars, catalytic converters in semi-trucks deal with bad substances emitted by diesel engines.

Inside these parts, however, precious metals are not that much.

Fortunately, you can protect your converter by enclosing it with a protective metallic box. Also, avoiding parking your truck away from people or a camera can be a great way to lower the chances of it getting stolen.

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