Diesel Fuel Cleanliness – What to Watch For

Maintaining cleanliness in diesel fuel is crucial for ensuring optimal engine performance and longevity. Contaminated fuel can lead to a range of problems, from reduced fuel efficiency to damage to fuel injectors and other engine components.

Things to Watch For

Water Contamination

Water can enter the fuel system through condensation or by mixing with contaminated fuel. Water in fuel is incredibly damaging and can include emulsified, dissolved, or free water. This can lead to corrosion, bacterial growth, hydrogen embrittlement, white edge cracking of the metals in contact, and reduced lubrication. Look for signs of water in the fuel, such as cloudiness or separation. Discovering as soon as possible and at the first indication that water is present goes a long way to identifying the root cause and correcting it.

Sediment and Particulate Matter

Dirt, rust, soot, and other solid particles can contaminate diesel fuel. These particles can clog filters, injectors, and other fuel system components. If left unchecked, particulate contamination will lead to engine system damage regardless of the age of the equipment. The buildup of particles accelerates filter plugging and leads to reduced engine and injector life possible early failure modes. Therefore, knowing and being confident of the fuel condition before it is in service is a vital process to have under control.

Microbial Growth (Diesel Bug)

Bacteria, fungi, and algae can grow in diesel fuel, especially if water is present. This can lead to clogged filters, fuel system corrosion, and degraded fuel quality.

Contaminants from Storage Tanks

If the fuel is stored in tanks, it’s important to ensure that the tanks are clean and free from rust, sediment, or microbial growth. Regular tank inspections and cleaning are essential.

Aging and Oxidation

Diesel fuel can deteriorate over time due to exposure to air, heat, and light. When is fuel is degraded through oxidation, it is more prone to create oxidation by-products (gums, varnishes, resins, deposits, etc.).  These by-products do not burn with the fuel during combustion.  Instead, they deposit and coat the inside of fuel lines, pumps, injectors, etc., clog filters prematurely, and interfere with the moving parts of low clearance areas in the fuel system. 

Additive Breakdown

If additives are used to enhance the properties of the fuel (such as detergents, stabilizers, or anti-gelling agents), their effectiveness can diminish over time.

Compatibility with Engine Specifications

Ensure that the fuel meets the specifications and requirements of your specific engine. Using fuel that doesn’t meet the required cetane rating or contains incompatible additives can lead to performance issues.

Preventive Measures

Proper Filtration and Water Separation

Regularly inspect and replace fuel filters to prevent contaminants from reaching the engine. Additionally, use water separators to remove any water present in the fuel.

Proper Handling and Storage

Minimize the chances of contamination during fuel handling and storage. Use clean equipment, avoid using dirty containers, and store fuel in clean, sealed tanks.

Regular Fuel Sampling and Testing

Periodic testing of fuel samples for water content, particulate matter, microbial growth, and other contaminants can help identify potential issues before they cause significant problems.

ReGular Maintenance & Monitoring

Remember, regular maintenance and vigilance are key to ensuring the cleanliness and quality of diesel fuel. If you suspect any form of contamination, it’s crucial to address it promptly to prevent damage to your engine and maintain optimal performance.

Additional Resources

Blog: 4 Common Diesel Fuel Issues & Effects
Blog: Baby It’s Cold Outside: Cold Weather & Diesel Fuel
Blog: Biodiesels and Cold Weather Don’t Always Mix