FREE SHIPPING when you send us your OEM converters!

NOBLE6 blog

Why Diesel Engine Catalyst Cleaning is Important

Maintaining clean diesel engine catalysts is essential for optimal engine performance and environmental care.

At noble6, we understand the impact of dirty catalysts on fuel efficiency, emissions, and overall engine health.

In this blog post, we will explore the effects of dirty catalysts, methods for cleaning them, and best practices for maintenance.

Why Clean Diesel Catalysts

Dirty diesel engine catalysts have a significant impact on several crucial aspects of engine performance and environmental health.

Reduced Fuel Efficiency

A clogged or dirty catalyst forces the engine to work harder, leading to increased fuel consumption. Studies have shown that dirty catalysts can cause a drop in fuel efficiency by up to 15%. This inefficiency translates directly into higher fuel costs and a larger carbon footprint.

Fact - Dirty catalysts can cause a drop in fuel efficiency by up to 15%.


  • Regularly inspect your catalyst for blockages.
  • Utilize cleaning products specifically designed for diesel systems, such as Rislone DEF Treatment, which can help maintain catalyst efficiency.

Increased Emissions and Pollution

A dirty catalyst struggles to convert harmful pollutants effectively. This failure leads to higher emissions of nitrogen oxides (NOx), hydrocarbons, and particulate matter. The EURO 6 regulations in Europe and EPA standards in the U.S. set stringent limits on these emissions. Failing to meet these standards can result in penalties and higher operating costs.

Decreased Engine Performance

Engine performance takes a direct hit when the catalyst is dirty. Symptoms include sluggish acceleration, reduced power, and potential engine misfires. A clogged catalyst restricts exhaust flow, causing backpressure that can harm your engine. According to research, up to 15% of diesel engine performance issues are linked to catalyst problems.

Actionable Tips:

  • Perform annual catalyst cleanings to prevent buildup.
  • Pay attention to changes in engine behavior; unusual symptoms might indicate a catalyst issue.
  • Use high-quality diesel exhaust fluid (DEF) to prevent crystallization and blockages in the catalyst.

Key Statistics:

  • Up to 15% drop in fuel efficiency due to dirty catalysts.
  • 50% reduction in NOx emissions required by EURO 6 standards.
  • 15% of engine performance issues are linked to dirty catalysts.

Maintaining a clean diesel catalyst is not just about compliance; it’s about optimizing your engine’s performance and contributing to a cleaner environment. Regular maintenance and using products designed for diesel systems can go a long way in ensuring your engine runs smoothly and efficiently. For more detailed information on related topics, consider reading about diesel oxidation catalysts.

How to Clean Diesel Catalysts

Chemical cleaning, ultrasonic cleaning, and manual cleaning are three primary methods to maintain the health of diesel engine catalysts. Each has its own advantages and practical applications.

Chemical Cleaning

Chemical cleaning involves using specially formulated products to dissolve and remove deposits from the catalyst. For instance, Rislone DEF Treatment helps dissolve white crystal deposits formed from contaminated DEF. This method is effective and straightforward, as it doesn’t require dismantling the engine. It’s also a method recommended for regular maintenance:

  • Regularly add cleaning agents to the DEF tank.
  • Follow manufacturers’ guidelines for the usage of chemical cleaners.
  • Always ensure that the chemical products are compatible with your SCR system to avoid damage.

Ultrasonic Cleaning

Ultrasonic cleaning utilizes high-frequency sound waves to dislodge and remove pollutants. This method is typically more effective than chemical cleaning, especially for severe blockages:

  • The process uses an ultrasonic cleaner filled with a solution, usually deionized water with a mild detergent.
  • Catalysts are immersed in the cleaner, where high-frequency waves create microscopic bubbles. These bubbles collapse on the surface, effectively cleaning the catalyst.
  • Best suited for deep-cleaning during major vehicle services.
Important - Ultrasonic cleaning is more effective for severe blockages compared to chemical cleaning.

Manual Cleaning

Manual cleaning involves physically removing the catalyst and cleaning it by hand. This method is labor-intensive but can be very effective for heavily clogged catalysts:

  • Remove the catalyst from the engine according to manufacturer guidelines.
  • Use a high-pressure water jet or air gun to clear out the particulate matter.
  • If necessary, soak the catalyst in a solution of water and dish detergent overnight to loosen stubborn dirt.
  • Avoid using harsh chemicals that might damage the catalyst structure.

Here are some tips to keep in mind for effective catalyst cleaning:

  • Inspect regularly: Look for signs of clogging and reduced performance.
  • Quality DEF: Use high-quality DEF to avoid crystallization and build-up.
  • Scheduled maintenance: Include catalyst inspection in your routine maintenance schedule.
  • Product choice: Use reputable chemical cleaners.

Proper cleaning not only enhances engine performance but also ensures compliance with stringent emissions regulations. Regular maintenance using these methods keeps your diesel engine running smoothly and efficiently.

How to Maintain Clean Catalysts

Maintaining clean diesel engine catalysts requires diligence and specific practices. Follow these steps to ensure your engine continues to operate efficiently and within emission standards.

Regular Maintenance Schedules

Sticking to a routine maintenance schedule is non-negotiable. Regular inspections and cleanings prevent buildup and identify potential issues early. Schedule inspections of your diesel engine catalyst at least once a year. Incorporate catalyst cleanings into your routine vehicle maintenance. Keep a record of all maintenance activities to track catalyst health over time.

High-Quality Fuel and Additives

Using high-quality diesel fuel and additives contributes significantly to keeping your catalyst clean. Choose diesel fuels that meet or exceed industry standards to minimize the risk of contaminants that can clog your catalyst. Integrate high-quality DEF products to prevent crystallization within the SCR system. Quality DEF like Rislone DEF Treatment can make a big difference in catalyst longevity.

Pro Tip - Choose diesel fuels that meet or exceed industry standards to minimize the risk of contaminants.

Monitoring Catalyst Health

Monitoring the health of your catalyst is essential for early detection of issues. Pay attention to the performance indicators in your vehicle. Poor acceleration, increased fuel consumption, or unusual exhaust emissions can signal a problem. Use diagnostic tools to check the efficiency of your catalyst regularly. Being proactive about monitoring can prevent costly repairs and ensure compliance with regulations.


  • Schedule annual catalyst inspections.
  • Opt for diesel fuel that meets industry standards.
  • Use high-quality DEF products.

Ensuring your diesel engine catalysts are well-maintained not only enhances engine performance but also helps meet stringent emission standards. Effective maintenance routines, high-quality fuel and DEF, and careful monitoring are key to a long-lasting and efficient catalyst.


Keeping diesel engine catalysts clean is vital for maintaining optimal engine performance and environmental care. Dirty catalysts can reduce fuel efficiency, increase harmful emissions, and undermine engine performance. Regular attention to catalyst health through scheduled maintenance, using high-quality DEF, and employing effective cleaning methods is essential to mitigate these issues.

Key Takeaways - Why Diesel Engine Catalyst Cleaning is Important

Key impacts of maintaining clean catalysts include:

  • Improved fuel efficiency by up to 15%
  • Significant reduction in NOx emissions as mandated by regulations like EURO 6
  • Enhanced engine performance with fewer issues

To ensure your diesel engine runs smoothly, adopt these best practices:

  • Perform annual inspections and cleanings
  • Use quality DEF products, such as Rislone DEF Treatment
  • Monitor catalyst health regularly

Diesel Catalyst Recycling

At noble6, we offer trustworthy and transparent recycling services for automotive precious metals, helping you maximize your profits while focusing on sustainability. We have a recycling program that is geared toward stationary/mobile power generation units fired by natural gas (Oxidation Brick) or diesel (Diesel Oxidation Catalyst-DOC/Diesel Particulate Filter-DPF). This includes fleet service organizations who work with large diesel internal combustion engines (Three Way Catalyst-TWC). Substrates that qualify for this recycling program include both ceramic and metallic foil catalyst. Selective Catalytic Reduction (SCR) has no recycling value. Find out more information HERE!


Catalytic Converter Recycling

Understanding the Rise and Fall of Catalytic Converter Prices

The catalytic converter recycling market has experienced significant fluctuations over the past few years. From soaring metal prices to the infiltration of organized crime, the…

Catalytic Converter Recycling

Catalytic Converter Recycling Industry Explained: Big Changes Ahead!

The catalytic converter recycling industry is a complex sector that plays a crucial role in the sustainable use of precious metals. This blog aims to…


Iridium Mine Production Dropping!

Explore the reasons behind the drop in iridium mine production, market implications, and future trends in the industry.