Do Diesel Engines Have Catalytic Converters?

The catalytic convertor is the most well-known part of car emission systems. Because of the amount of precious metal inside, this valuable part is frequently stolen from gas-powered vehicles and trucks. This might make you wonder if diesel engines are equipped with catalytic converters.

This guide answers that crucial question. This guide also explains how it works with diesel-powered motors. Plus, we look at ways to tell when it’s time to replace the diesel catalytic converter.

Do Diesel Engines Have Catalytic Converters?

Many diesel cars do not have the same catalytic converter as the gasoline-powered ones. There are some diesel engines that have a 2-way catalyst and a diesel-oxidization catalyst. Others may use a 3-way converter which reduces the SCR. 

Diesel engine emissions go through four stages: there’s the EGR (Exhaust Gas Recirculation), as well as the DPF (Diesel Particulate Filtration), plus the DOC (Diesel Oxidization Catalyst) and the SCR (Selective Catalytic Reduction). The catalysts produce chemical reactions that reduce the emissions in the DOC/SCR stages.

How does the Diesel Catalytic converter work?

It is responsible to convert harmful substances into non-toxic forms. The metal enclosure houses two ceramic blocks, which look like a honeycomb. 

The ceramic blocks are coated with a metal, like palladium and platinum. The engine is closer to the catalytic converter, where the converter heats up to catalyze chemical reactions. The reactions transform toxic gases into benign byproducts, which can then be released to the atmosphere.

It Diesel Oxidation Catalyst The functions of a gasoline engine's combustion engine (DOC) are very similar. Metal catalysts are used to reduce carbon monoxide into water and carbon. This is when volatile hydrocarbons, as well as byproducts, are converted into more harmless substances. As a result, dangerous gas emissions are decreased. However, this cat doesn’t contain rhodium, as the gas engine does. It also includes a diesel particulate filter (DPF) that eliminates the particulate matter that isn’t found in the gas-centered converter.

SCR is responsible to break down Nitrogen Oxide (NOx) An ammonia-based catalyst can convert Nitrogen into Oxygen. The open loop system reduces NOx emissions from 75 to 90%. Hydrocarbon emission reductions can also be achieved by using SCR, although it is only 8% effective. Low sulfur fuel can improve performance. 

How Long Does A Diesel Catalytic Converter Last?

It could live for about 100,000 miles. The health of the catalytic converter depends on how often you drive and what your vehicle's maintenance is. The catalytic converter may fail prematurely if you take short trips. 

The engine is turned off during shorter journeys so the converter can reach the correct operating temperature for catalyzing the compounds. This causes more wear to the converter. 

A Failed Diesel Catalytic Convertor

Recognize the warning signs and have the converter repaired immediately. The converter may fail prematurely for any reason. Among the leading causes of premature failure are:

• The restriction on exhaust gas flow is to prevent free circulation
• Carbon deposits are being built up
• Inflicted physical damage
• Overheating
• Poor engine maintenance

Modern cars have oxygen sensors which help to determine whether the catalytic convertor is needed. When the oxygen sensors don’t receive the proper reading, they cause the Check Engine Light to come on. You can use a code scanner to figure out what’s causing the issue.

You might notice the Check Engine Light and these other symptoms to indicate that your catalytic converter may be failing.

Related: 8 Signs that a Catalytic Converter is Clogged or Bad

Diesel Catalytic Converter Replacement Cost

Having the catalytic converter replaced isn’t going to be an inexpensive job. It’s just as expensive or more expensive than with a gas-powered car. You can expect to pay between $900 and $2500 depending on which car you have and what the converter material is. This includes parts as well as labor.

You can save some money if you do it yourself. The majority of costs for replacing the part are covered by the cost of shipping it. 

It is expensive to buy a catalytic converter. To prevent theft, some drivers opt to add theft-proof features to their catalytic converters. The catalytic convert can be easily protected against thieves for as low as $50 

RELATED: What Does it Cost to Replace a Catalytic Convertor?

Is the Car able to run without a diesel catalytic converter?

There’s nothing stopping the vehicle from driving with the catalytic converter missing. The engine is still going to work and you won’t be stranded without it. However, the emissions standards won’t be the same and you could notice some engine performance problems.

The law also requires that catalytic converters be installed. Without one, your vehicle could result in stiff fines. You aren’t responsible for getting an emissions test, so that’s not the problem, but the safety inspection could flag it when you go to renew your registration. 

Is Catalytic Converter Cleaning Effective?

The catalytic converter can get clogged as carbon buildup. Some people assume this means that the only option is to replace the catalytic converter, but that’s not the case. Some products claim they can clean the catalytic convert. 

While there’s a lot of controversy over whether these catalytic cleaner products work, most people agree that it’s worth trying. A simple cleaner can save you the cost of a converter.

RELATED: Cleaning a Catalytic Convertor (Without Removing It)

Some people also find that a catalytic cleaner helps prolong the useful part's life. Many products recommend that you use a bottle of cleaner every 3000 to 4000 miles. However, this is too much. It should produce results when you only use the product twice per year and drive an average amount of miles.