Is Biodiesel Truck Compatible with Standard Diesel Fuel?

Man putting a yellow gasoline pump nozzle into his car in a pump gas station

In the world of sustainable transportation, biodiesel trucks have emerged as a green alternative to their traditional diesel counterparts. But a question often arises: Is it possible to use standard diesel in a truck designed for biodiesel? The answer to this inquiry is not only fundamental to truck owners but also pivotal for the broader adoption of biodiesel vehicles.

Table of Contents

  1. Is Standard Diesel Fuel Compatible with a Biodiesel Vehicle?;
  2. Characteristics of Biodiesel Fuel;
  3. Defining a Biodiesel-Compatible Truck;
  4. Considerations for Switching to Biodiesel Fuel:
    • Material Compatibility in Fuel Systems;
    • Impact of Fuel on Tank Metals;
    • Oil Dilution in Engines;
    • Fuel Injector Equipment Wear;
    • Impact on Emission Control Systems.
  5. Drawbacks of Opting for Regular Diesel Instead of Biodiesel;
  6. Is an Engine Modification Required for Switching Fuels?;
  7. Challenges of Biodiesel Compared to Regular Diesel;
  8. Is Gasoline Corrosive?:
    • Is Gasoline Corrosive to Metal?;
    • Is Gasoline Corrosive to Plastic?.
  9. Conclusion.

Is Standard Diesel Fuel Compatible with a Biodiesel Vehicle?

Exploring the feasibility and implications of utilizing standard diesel in a vehicle designed for biodiesel, which is often referred to as B100, denoting 100% biodiesel composition. The “B” stands for biodiesel, and the accompanying number indicates the percentage of biodiesel in the blend.

Is it possible to fill a biodiesel truck with standard diesel? The answer is affirmative. Diesel engines in trucks are versatile, allowing for the use of both regular diesel and biodiesel. Standard diesel often comes mixed with biodiesel in ratios such as B20 (20% biodiesel with 80% standard diesel) and B5 (5% biodiesel mixed with 95% standard diesel).

Characteristics of Biodiesel Fuel

Biodiesel stands out as an environmentally friendly option, outperforming other petroleum fuels with its biodegradability and cleaner combustion. It enhances the cetane number, leading to improved fuel quality, prompt engine start-ups without hesitation, and heightened lubrication. This fuel can be used in any engine without the need for modifications. While pure biodiesel can be used to create lower-concentration blends with standard diesel, it is not typically used in vehicle transportation in its pure form. The lubricating properties of biodiesel extend the lifespan of engine components by reducing wear and tear. Additionally, biodiesel acts as a cleaning agent, eliminating residue build-up in fuel tanks. This may initially lead to clogged filters and injectors, but over time, reduces the necessity for frequent fuel filter replacements. Trucks can efficiently run on either standard diesel or biodiesel without compromising performance.

Defining a Biodiesel-Compatible Truck

Contemporary truck models are designed to accommodate biodiesel fuel seamlessly, negating the need for engine modifications. Trucks currently in service are capable of using B5, a blend containing 5% biodiesel.

Newer trucks are engineered to operate effectively on blends like B20, which consists of 20% biodiesel mixed with 80% traditional petroleum diesel, and this biodiesel percentage is anticipated to rise over time.

Considerations for Switching to Biodiesel Fuel

It’s important to consider several key aspects before transitioning a truck to run on a different type of fuel.

Material Compatibility in Fuel Systems

Designers of fuel systems undertake a variety of lab tests to determine how different fuels will react with the materials used to construct the fuel tank system.

  • Switching the fuel composition in a vehicle’s fuel system without adequate testing can lead to numerous issues, particularly with metallic components like gaskets, oil filters, O-rings, and seals.

Impact of Fuel on Tank Metals

It’s crucial to evaluate the interaction between diesel and the metal composition of the fuel tank’s interior, which may include copper, brass, aluminum, and steel.

  • Fuel tanks composed of copper or copper-related materials such as brass and bronze are prone to severe corrosion if the fuel is altered without prior testing;
  • Copper, in particular, can lead to gum formation when used with biodiesel;
  • Zinc and its alloys are significantly incompatible with biodiesel;
  • On the other hand, steel and aluminum are susceptible to increased acid production that can erode various parts of the fuel system.
wo silver trucks on the road, the grass and trees on both sides of the road

Oil Dilution in Engines

Oil dilution refers to the process where the oil content in an engine increases due to the inadvertent mixing of fuel with the engine oil.

  • This issue is particularly prevalent in diesel engines, often arising during the post-injection phase, which is intended to purge the filters and other components of the fuel system;
  • During the cleaning cycle, while some diesel is expelled as exhaust gases, a residual amount may adhere to the chamber walls, eventually seeping into the engine;
  • This dilutes the engine oil, compromising its lubricating properties and affecting the engine’s performance and efficiency.

Fuel Injector Equipment Wear

Problems with fuel injectors and filters can significantly impact engine performance. Symptoms of clogged fuel injectors include misfires and difficulties in starting, often indicated by spark plug and ignition coil issues.

Frequently, these issues arise from the use of stale fuel, which accumulates and adheres to the filters and the nooks of the injector assembly. Severely clogged injectors usually require removal and thorough cleaning to restore function.

Impact on Emission Control Systems

The emission control systems in vehicles, designed to reduce exhaust emissions, can be adversely affected by changes in the fuel composition. Such alterations can lead to increased emissions, undermining the efficiency of these post-treatment systems.

Drawbacks of Opting for Regular Diesel Instead of Biodiesel

Several disadvantages are associated with using regular diesel in comparison to biodiesel, which has gained preference as a fuel choice.

  • A primary concern is the higher emission levels of gases and pollutants from regular diesel during combustion. Biodiesel is known to produce approximately 10-12% less carbon monoxide and 9-11% fewer pollutants;
  • Regular diesel combustion releases sulfur, benzene—a known carcinogen, and nitrogen oxides, which biodiesel, a more bio-friendly fuel, does not. Biodiesel’s lack of sulfur emissions makes it a key player in reducing environmental pollution, earning its reputation as an eco-friendly alternative;
  • Furthermore, biodiesel produces fewer harmful chemicals than regular diesel. Modern vehicle engines are designed to be compatible with both types of fuel, but biodiesel is often the preferable option;
  • Biodiesel also enhances the lubricity of an engine, surpassing the capabilities of standard petroleum-based oils;
  • With a higher oxygen content, ranging from 11-14%, biodiesel supports more complete combustion than regular diesel, which has a lower oxygen percentage;
  • Acting as a chemically active solvent, biodiesel readily reacts with other substances, making it safer to blend with petroleum fuels compared to regular diesel.

Is an Engine Modification Required for Switching Fuels?

Switching your engine to accommodate regular diesel isn’t necessary when using a biodiesel tank, as biodiesel is typically blended with regular diesel.

However, trucks manufactured before 1993 may require a replacement of the rubber fuel lines before utilizing this blend. Modern trucks come equipped with a diesel particulate filter that can handle both types of fuel. Yet, this filter can lead to oil/fuel dilution issues. For those using regular diesel, it may necessitate daily filter changes.

On the other hand, if you opt for biodiesel, the filter should be changed after every 2,700 miles, alongside regular fuel level checks.

Challenges of Biodiesel Compared to Regular Diesel

While regular diesel is typically consistent and reliable in quality, the same can’t always be said for biodiesel. The quality of biodiesel can vary significantly depending on the source and location, and this inconsistency is particularly notable in smaller-scale production.

This variability in quality can lead to performance issues in truck engines. Another challenge with biodiesel is its tendency to thicken at lower temperatures, a problem especially in colder regions. This is a key reason why biodiesel is often used in a blended form.

a woman with a gasoline red pump nozzle in a gas station

Is Gasoline Corrosive?

Gasoline is a complex chemical mixture and its corrosive properties can vary based on its composition. Generally, gasoline is not highly corrosive, but it can have corrosive effects under certain conditions or when mixed with other substances.

Is Gasoline Corrosive to Metal?

Gasoline itself is not typically corrosive to metals such as steel or aluminum, which are commonly used in fuel systems. However, certain additives in gasoline, like ethanol, can attract moisture, leading to rust and corrosion over time, especially in older fuel systems not designed for ethanol-blended fuels. The presence of ethanol can also lead to corrosion in components made of certain alloys or metals.

Is Gasoline Corrosive to Plastic?

When it comes to plastic, the impact of gasoline largely depends on the type of plastic. Some plastics, like high-density polyethylene (HDPE), are resistant to gasoline and are commonly used in fuel containers and tanks. However, other types of plastics can degrade, swell, or become brittle when in prolonged contact with gasoline, especially if the gasoline is blended with ethanol or other additives. This is particularly a concern in older vehicles or equipment where the plastic components were not designed to handle ethanol-blended gasoline.


In summary, biodiesel trucks provide a sustainable alternative in transportation, compatible with both standard diesel and biodiesel fuels. Despite environmental benefits such as reduced emissions, biodiesel faces challenges like quality variability and cold-weather issues. Regular diesel offers consistent quality but has higher emissions and potential corrosion problems, particularly in older systems. Gasoline, while not corrosive to metal, can adversely affect certain plastics and older fuel systems. This underscores the importance of thoughtful fuel selection, considering environmental impact, engine compatibility, and performance needs.

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