Is B20 diesel bad for your truck?
B20 diesel is not inherently bad for modern trucks. In engines and fuel systems that are approved for B20, it can be safe and offer certain benefits. Issues are more likely with older equipment, lower-quality biodiesel, or when OEM guidance isn’t followed.
What is B20 and how does it work?
B20 is a diesel fuel blend containing 20% biodiesel and 80% petroleum diesel. Biodiesel is typically produced from fats and oils, such as soybean or canola oil, waste cooking oil, or other feedstocks. For reliability and consistency, biodiesel and blends sold in the United States are regulated to meet standards such as ASTM D6751 (biodiesel quality) and ASTM D7467 (the blend specification). Biodiesel has different chemical properties than petroleum diesel, including higher lubricity, a different solvent profile, and a tendency to absorb more water. When used in engines that are approved for B20, most drivers don’t notice a dramatic change in operation, though performance, emissions, and maintenance considerations can vary with climate, fuel quality, and engine design.
Benefits of B20 for trucks
Below is a summary of the main advantages reported by fleets and drivers using B20 in compatible engines:
- Increased lubricity in the fuel, which can reduce wear on fuel injectors and pumps.
- Lower sulfur content in the blend compared with ultra-low-sulfur diesel, contributing to cleaner combustion and reduced sulfur emissions.
- Potential reductions in some pollutants, especially particulate matter and certain carbonaceous emissions, depending on the feedstock and engine calibration.
- Support for renewable fuels and a lower lifecycle reliance on petroleum-based diesel when produced from waste or non-food feedstocks.
- Often comparable power and fuel economy to standard diesel in engines designed to tolerate biodiesel blends.
In practice, these benefits are most pronounced when B20 is used in engines that have OEM approval for the blend and when the biodiesel meets high-quality standards and is properly stored and handled.
Potential drawbacks and risks
Although B20 can be a fit for many trucks, there are caveats to consider before fueling up:
- Compatibility concerns: Older engines, seals, hoses, or fuel-system components not rated for biodiesel blends may experience accelerated wear or swelling. Always verify OEM approval for your specific model and year.
- Water absorption and microbial growth: Biodiesel can attract and retain water, which can lead to corrosion, fuel degradation, or microbial fouling if moisture isn’t controlled and the fuel is stored improperly.
- Cold-weather performance: Biodiesel’s cloud point and pour point are higher than petroleum diesel in many feedstocks, raising the risk of gelling in cold conditions. Winterized biodiesel or temperature-appropriate blends are often recommended.
- Deposit and filter considerations: Biodiesel can loosen deposits and cause temporary fuel-system cleaning effects, which may lead to transient fuel filter plugging if there are already deposits in the tank or lines.
- Emissions variances: NOx emissions can increase slightly in some engines running biodiesel blends; effects vary by engine design, tuning, and aftertreatment systems.
- Warranty and service considerations: If your vehicle’s warranty requires a B20 approval from the manufacturer and you use a non-approved batch, you could risk warranty coverage.
With proper fuel quality, climate-appropriate blending, and OEM guidance, these risks can be mitigated. It’s important to follow manufacturer recommendations and use biodiesel that meets the relevant ASTM standards.
OEM approvals, warranties, and maintenance considerations
Before adopting B20, check your truck’s documentation and consult the manufacturer or dealer. Not all engines are approved for every year or variant of B20, and warranty coverage can hinge on official approval and correct fuel specifications.
- Verify that your engine and fuel system are explicitly approved for B20 by the original equipment manufacturer (OEM) for your model and year.
- Use ASTM-compliant biodiesel (typically ASTM D6751) and ensure the blend meets ASTM D7467 standards.
- Ask about any required maintenance changes, such as filter schedules or fuel-system inspections, when switching to B20.
- Be aware of potential warranty implications if using a blend not approved by the OEM.
- Choose a reputable biodiesel supplier with good storage and delivery practices to minimize water and contamination.
In practice, the best path is to confirm compatibility with your specific truck and to source high-quality, well-specified B20 biodiesel from a trusted supplier. This helps protect both performance and warranty status.
Practical steps for using B20 in your truck
If you decide to use B20 after confirming OEM approval, follow these practical steps to maximize reliability:
- Confirm B20 approval with your vehicle’s manufacturer for your exact model, year, and engine configuration.
- Source biodiesel that meets ASTM D6751 and ensure the fuel refiner or distributor provides documentation of fuel quality.
- Keep fuel storage in a clean, dry environment to minimize water contamination; use additives if recommended by the biodiesel supplier or OEM.
- Monitor fuel filters and fuel-system performance after switching; be prepared for a possible temporary rise in filter change frequency as deposits are cleared.
- In cold climates, use winterized biodiesel or timely switching to a lower biodiesel percentage during colder months as recommended by OEM guidelines.
Following these steps can help ensure smooth operation and minimize the risk of issues when running B20.
Summary
For most modern diesel trucks, B20 is not inherently dangerous and is widely used in fleets and consumer vehicles that have OEM approval. The key factors are engine compatibility, fuel quality, climate conditions, and adherence to established standards (ASTM D6751 and D7467). Older engines or unapproved installations carry higher risk of seal compatibility problems, water-related issues, and warranty concerns. Always verify with the manufacturer, choose high-quality biodiesel, and follow maintenance practices to reap potential benefits while avoiding common pitfalls.
Does biodiesel damage engines?
Yes, biodiesel can be bad for engines, especially older ones, because it can degrade certain rubber seals and hoses, and its solvent properties can clog fuel filters. However, using it in modern engines is less likely to cause problems, as they are often built with compatible materials. Poorly made biodiesel can also cause issues, so it is crucial to use high-quality fuel and consider potential cold-weather and engine-idling limitations.
Potential problems with biodiesel
- Material degradation: Biodiesel can degrade natural rubber, some plastics, and other non-synthetic materials, requiring older engines to have their fuel lines and seals replaced with modern, compatible synthetic ones.
- Clogged fuel filters: Biodiesel's cleaning properties can loosen deposits from the fuel tank and lines, which then collect in the fuel filter and cause it to clog.
- Poor cold-weather performance: Biodiesel can gel or solidify at higher temperatures than petrodiesel, which can cause issues in cold weather. This is why some suggest avoiding it in freezing temperatures or using a pre-heater.
- Fuel injector deposits: In some cases, poorly made biodiesel can leave deposits on fuel injectors, affecting the spray pattern and causing symptoms like misfiring or hard starting.
- Reduced fuel efficiency: Biodiesel has a lower energy content than petroleum diesel, which can lead to slightly lower fuel economy.
- Issues in modern engines: Some modern diesel engines, especially those with high fuel pressures and temperatures, can also experience issues with biodiesel due to its tendency to oxidize and cause breakdown in the fuel system components over time.
How to mitigate potential problems
- Use high-quality fuel: Ensure you are using a high-quality, properly manufactured biodiesel blend.
- Perform regular maintenance: Change your fuel filter more frequently, especially when you first switch to biodiesel, to manage any loosened deposits.
- Upgrade engine components: In older engines, replace any non-compatible rubber or plastic parts in the fuel system with materials like synthetic rubbers and compatible hoses.
- Be cautious in cold weather: Avoid using biodiesel in very cold temperatures unless your vehicle is equipped with a fuel heater.
- Avoid prolonged idling: Do not idle for more than a few minutes at a time when running on biodiesel, as this can prevent the engine from reaching the temperature needed to regenerate the diesel particulate filter (DPF) and may cause it to plug up sooner.
What is the downside of biodiesel?
One of the major problems faced by the use of biodiesel is increased emission of NOx which can result in the formation of smog and acid rain. Biodiesel has lower energy output as compared to petro-diesel. Hence, in order to get the same amount of energy, more biodiesel is used than petro-diesel.
Is biodiesel bad for your truck?
Deposits and clogging: deposits and clogging due to biodiesel have been widely reported but are generally traceable to biodiesel that is either of low quality or has become oxidized. If fuel quality is high, deposits in the engine should not normally be a problem.
Can I use B20 diesel in my truck?
You can likely use B20 diesel in your truck, but you should first check your owner's manual and warranty to ensure it's approved for your specific engine. While most modern diesel engines can handle B20 blends without modification, some older vehicles may require it, and certain manufacturers have specific recommendations or restrictions, like limits on usage during very cold weather or more frequent filter changes.
Things to consider before using B20
- Check your warranty and manual: This is the most important step. Some manufacturers do not approve of blends higher than B5 (5% biodiesel), and using a non-approved fuel could void your warranty.
- Consider engine age: Older diesel engines might not be compatible with B20 and could require modifications to the fuel system.
- Be mindful of cold weather: Biodiesel can gel more readily than conventional diesel in cold temperatures, which could cause fuel flow problems. Check the recommendations for your climate, as B20 is often not used or sold in colder regions during winter.
- Potential for fuel system cleaning: Biodiesel can act as a solvent, potentially loosening deposits from the fuel tank and lines. This may require more frequent fuel filter changes initially, especially for some vehicles like certain Mercedes models.
- Potential for better lubricity: B20 can improve fuel lubricity, which can be beneficial for the fuel injection system.
How to decide
- If your vehicle's manual and warranty allow B20, and you are not in a consistently very cold climate, it is generally a safe option.
- If you are still unsure, stick to B5 or lower, which is approved by nearly all engine manufacturers.
