Diesel fuel is a byproduct of crude oil, a natural mineral resource from the earth. The process of refining crude oil produces gasoline, diesel, kerosene, etc., and all these byproducts have their unique purposes.
As a major byproduct of crude oil, diesel fuel comes in different varieties, which are distinguished by their colors. Now, you may be wondering, “What color is diesel fuel?”
The different types of diesel fuel and their colors have been exposed below in this article. Now, let’s find out what is diesel and the various types of diesel fuel.
What is diesel fuel and why is it used?
Diesel fuel, a complex blend of hydrocarbons, serves as the primary fuel for diesel engines. Derived from crude oil, it comprises a diverse range of natural compounds with varying boiling points.
The hue of diesel fuel stems from its unique chemical composition, predominantly composed of long-chain hydrocarbons. These hydrocarbons are intricate molecules formed by the bonding of numerous carbon atoms.
Diesel fuel engines are designed differently from gasoline engines, which require spark plugs to ignite the fuel in order to produce power. In diesel engines, the fuel is ignited through a process of pressurization and compression.
Diesel fuel is known for its high energy content, which makes it a more efficient fuel source for vehicles. It is also more commonly used in larger vehicles such as trucks and buses due to its ability to handle heavier loads.
Overall, diesel fuel plays an important role in the functioning of many vehicles, especially those used for heavy-duty purposes.
What Color Is Diesel Fuel?
Diesel fuel comes in two colors — clear and red. After processing and refining, diesel is clear. However, different industries and users need diesel for their applications, so clear diesel is dyed to show its intended purpose.
Clear diesel might have a greenish tint when it’s fresh or a yellow tint when it’s older. Red diesel, also referred to as off-road diesel, is artificially dyed to look reddish so officials and users can identify it clearly.
Types of Diesel Fuel
Before you can understand the difference between regular diesel and dyed diesel fuel, you need to understand what constitutes “regular” diesel. There are several types of diesel fuel available for public purchase:
#1. Petroleum diesel.
When most people hear the word “diesel,” there is a good chance petroleum diesel is the first type that comes to mind.
This is the most common diesel type and is also known as fossil diesel. Petroleum diesel is derived from distilling crude oil into liquid fuel. It is used to power trucks, trains, buses, boats, planes, and more.
#2. Synthetic diesel.
Synthetic diesel is a low-sulfur alternative to petroleum diesel. It can be created from any carbonaceous material, such as coal, natural gas, or biomass.
The natural substance is gasified, purified, and transformed into hydrocarbons nearly indistinguishable from those found in standard petroleum fuels. The lower sulfur content reduces emissions, making it a more ecologically friendly fuel choice.
#3. Biodiesel.
Biodiesel can be made from vegetable oil, animal fats, or even old restaurant grease. This makes it a renewable fuel source, unlike diesel derived from oil or coal.
Most biodiesel is created from soybean, corn, or canola oil. It can be blended with petroleum diesel in varying quantities, although not all machinery can accept diesel with a high concentration of biodiesel in it.
#4. Hydrogenated oils and fats.
To create this fuel, triglycerides naturally found in vegetable oil and animal fat are converted into alkanes. This makes the fuel similar to synthetic diesel.
#5. Dimethyl Ether (DME).
DME is a synthetically produced, clean-burning, non-toxic fuel with discreet combustion and a high cetane value. Using it as a fuel source creates less carbon emissions than traditional petroleum diesel.
What Is The Normal Diesel Fuel Color?
Aside from the color, there aren’t many differences between the different types of diesel fuel. You have on- and off-road diesel available, each meant to be used in different applications. There’s also a type used strictly by the government.
Let’s look at the three colors of diesel fuel available today.
#1. Clear Diesel.
Regular on-road diesel fuel is clear by nature. It may also have a slightly green tint to it from the refinery.
If you look at fresh diesel from the fuel pump, these are the only two colors you should see. If the color looks more yellow or slightly darker, it could be old and should be avoided.
Ultra-low-sulfur diesel (ULSD) has lower sulfur contents than conventional diesel. Since 2016, nearly all of the petroleum-based diesel fuel available is ULSD.
#2. Red-Dyed Diesel.
When diesel has a red dye in it, it’s meant only for off-road use in the United States. This dye is placed in the diesel fuel to ensure it’s only used for off-road vehicles and equipment.
What makes the red diesel different isn’t the composition. In fact, other than the dye, it’s the same fuel as the clear type. It only shows that this fuel wasn’t taxed the way on-road fuel is. This dye comes from a chemical additive that is normally either Red 26 or 164.
You can use the red dye diesel in any off-road vehicle. It can also be used in other off-road applications, such as in your generator, for heavy construction equipment or your farm tractor, as long as you aren’t taking these items on the road.
#3. Blue-Dyed Diesel.
Again, here’s a different color diesel fuel that isn’t any different from what you get at the pump other than the hue it exhibits. The blue-dyed diesel is also considered an off-road variant.
However, this diesel fuel isn’t meant for use by the public. You can’t go buy blue diesel at any local pumps.
It’s only intended for use in government vehicles and equipment in the United States. Again, this type of diesel fuel isn’t meant to be used for on-road use, even by the government.
#4. Green Dye Diesel.
Green dye diesel is often associated with alternative fuels like biodiesel and used for off-road equipment. This distinct color serves as a visual cue, indicating a unique fuel blend that includes renewable sources, hence its more expensive price.
Unlike traditional diesel options, green dye diesel aligns with environmentally friendly practices and reduced carbon footprints. Its application extends beyond conventional diesel engines, emphasizing a commitment to sustainable energy solutions.
How to Know Your Diesel Fuel Is Legal
Government officials can test your fuel at weigh stations, agricultural shows, safety check stations and other areas if they think you’re using the wrong fuel.
Therefore, it’s important to understand the differences between either diesel type and purchase your diesel from a reliable supplier.
Use these tips to ensure you’re getting the right fuel for your needs:
- Check the fuel source: Getting the correct fuel starts at the source. Make sure you and your supplier know what fuel you require for your vehicle and its intended use. Authorized fuel sellers and suppliers will have the information you need to get regulation-compliant fuel.
- Look at color: Is your fuel red or clear? Visual checks are a fast way to find out what fuel you have. You can also get a fuel analysis kit to make sure your fuel is the right color and composition. If you have the wrong fuel, let your supplier know and remove it to avoid legal fines.
- Keep records: Document all your fuel purchases to cover your bases. Receipts and delivery notes will indicate the type of fuel you buy — keep these records in a safe place. This documentation can come in handy if you’re ever questioned about your fuel use or found using the wrong fuel.
- Store safely: Store your diesel in clearly labeled containers or tanks to avoid accidental swaps. Keep your off-road and clear diesel separate with accurate labels so you only use the correct one.
- Stay updated: Stay current with local and federal fuel regulations. Conducting fuel audits and regularly refreshing your knowledge ensures you’re always aware of proper fuel use.
Dyed Diesel Vs Clear Diesel: The Difference
Dyed and clear diesel may share similar chemical additive compositions, but their distinctions lie in purpose, taxation, and application.
Clear diesel is the standard fuel used in on-road vehicles and equipment. Its transparent appearance signifies the absence of dyes or additives, making it suitable for general automotive use.
On the other hand, dyed diesel is marked with a distinct color, commonly red, blue, or green, to indicate its designated use and tax status.
Red dye diesel, for example, is intended for off-road applications, such as farm equipment and construction vehicles, and benefits from tax exemptions.
This dye acts as a visual cue, allowing authorities to easily identify if the fuel is being used improperly for on-road purposes. The color signifies a unique fuel blend and promotes awareness to prevent accidental use in standard diesel engines.
Importance of Diesel Fuel Color
Diesel fuel color may seem like a trivial aspect when it comes to fuel quality, but it can actually provide valuable information about the fuel’s condition and potential engine problems.
By understanding the significance of diesel fuel color, we can gain insights into fuel quality and identify any contaminants that may be present.
#1. Indication of Fuel Quality.
The color of diesel fuel can serve as an indication of its overall quality. Generally, clear or light yellow diesel fuel is considered to be of good quality. This color suggests that the fuel has undergone proper refining processes and contains minimal impurities.
On the other hand, dark brown or black diesel fuel may suggest a lower quality fuel that has not been properly refined or may have been contaminated.
Additionally, a cloudy or milky appearance in diesel fuel indicates the presence of water or other contaminants, which can negatively affect the fuel’s performance.
#2. Identification of Contaminants.
Apart from fuel quality, diesel fuel color can also help us identify potential contaminants that may be present. Contaminants in diesel fuel can range from dirt and sediment to bacteria and fungi.
These contaminants can cause clogging in fuel filters, fuel injectors, and other components of the fuel system, leading to decreased engine performance and potential damage.
By visually inspecting the color of diesel fuel, we can identify the presence of certain contaminants. For example, a reddish or pink hue may indicate the presence of bacteria or fungi, which can thrive in the presence of water.
These microorganisms can form colonies in the fuel system, leading to fuel degradation and potential engine problems.
Similarly, the presence of sediment or particles in diesel fuel can be identified by a darker or cloudier color.
These contaminants can result from improper storage or handling of the fuel, and they can cause blockages in the fuel system, reducing the fuel flow and affecting engine performance.
Factors Affecting Diesel Fuel Color
There are several factors that can affect the color of diesel fuel, including age and oxidation, as well as the use of additives and dyes.
#1. Age and Oxidation.
One of the primary factors that can influence the color of diesel fuel is its age and the process of oxidation.
As diesel fuel ages, it can become darker in color. This is because over time, the fuel undergoes a chemical reaction with oxygen, resulting in the formation of various compounds that contribute to the darkening of the fuel.
Oxidized diesel fuel may also develop a cloudy or milky appearance due to the formation of particulate matter.
These particles can be a result of the breakdown of fuel components or the presence of contaminants. Additionally, the oxidation process can lead to the formation of sediments and sludge, which can further impact the fuel’s color and quality.
#2. Additives and Dyes.
Another factor that can affect the color of diesel fuel is the use of additives and dyes. Additives are commonly used in diesel fuel to enhance its performance and improve its stability.
These additives can include detergents, corrosion inhibitors, and cetane improvers, among others.
Some additives, such as cetane improvers, may have a slight impact on the color of diesel fuel. Cetane improvers are additives that enhance the combustion properties of diesel fuel, resulting in better engine performance.
These additives typically have a light yellow color, which can contribute to a clearer or lighter yellow appearance of the fuel.
In addition to additives, dyes are sometimes used to color diesel fuel for identification purposes. Dyes are typically added to differentiate between different types of diesel fuel, such as off-road and on-road diesel.
For example, red dye is often used to indicate off-road diesel, while on-road diesel is typically colorless or has a light yellow color.
It’s important to note that the use of additives and dyes should comply with fuel quality standards and regulations. These standards ensure that the additives used in diesel fuel do not negatively impact its performance or pose any risks to the engine or the environment.
Overall, the factors affecting diesel fuel color are multifaceted. Age and oxidation can darken the fuel, while additives and dyes can introduce different hues.
By understanding these factors, you can gain insights into the quality and condition of the diesel fuel, which can help identify potential engine problems or issues with fuel quality.
How to Maintain the Quality and Color of Diesel Fuel
Proper maintenance of diesel fuel is essential to ensure it meets regulatory standards, operates efficiently, and prevents damage to your machinery.
Understanding and implementing the right storage practices, using high-quality fuel, and employing additives and filtration can all help in maintaining the integrity of your diesel fuel.
#1. Proper Storage.
Storing diesel fuel correctly is crucial for preserving its quality and color. Tanks should be kept in a cool, dry place, away from direct sunlight and heat sources. Ensure tanks are sealed tightly to prevent air from entering, which can lead to oxidation and contamination.
#2. Use High-Quality Fuel.
Always source your diesel from reputable suppliers. High-quality diesel fuel is less likely to contain harmful impurities and is typically treated to withstand longer storage durations without degradation. Look for certifications and standards that guarantee the diesel’s quality.
#3. Filtration.
Using fuel filters is an effective way to remove contaminants like dirt, water, and microbial growth. Regularly check and replace these filters to ensure they function correctly. Proper filtration can extend the life of your fuel and the equipment it powers.
#4. Additives.
Additives can enhance the performance and longevity of diesel fuel. Common additives include stabilizers to prevent oxidation, biocides to control microbial growth, and anti-gel agents to keep the fuel flowing in low temperatures. Always follow the manufacturer’s guidelines for additive use.
#5. Regular Inspections.
Conduct regular inspections of both your fuel and storage tanks. Look for any signs of contamination, unusual odors, or changes in color. Regular testing can help identify issues early, allowing for timely intervention and minimizing potential damage.
#6. Tank Maintenance.
Clean and maintain storage tanks routinely. This includes draining and cleaning the tank to remove sludge and sediment that can accumulate over time.
Proper maintenance ensures that your storage system remains free of contaminants that could compromise your fuel’s quality.
#7. Temperature Control.
Diesel fuel can be sensitive to temperature changes. Extreme cold can cause fuel to gel, while high temperatures can accelerate degradation.
Store tanks in temperature-controlled environments, and consider insulation or heating elements for outdoor tanks in cold climates.
#8. Prevent Contamination.
Make sure all equipment used to handle diesel, such as pumps and hoses, is clean and in good condition.
Avoid using containers that previously held other substances, as residual materials can contaminate the diesel fuel. Ensuring a clean transfer process is crucial in maintaining fuel integrity.
Why Does The US Government Regulate Diesel?
According to the Environmental Protection Agency (EPA), the sulfur amount in diesel fuel is linked to pollution after it’s been burned in the car engine.
The higher the levels of sulfur, the more pollution there is. As diesel fuel gets burned, the emissions resulting from the use contribute to air pollution, which has an effect on human health as well.
Some of the pollution coming from the exhaust of diesel fuel vehicle include the following:
- Soot/particulate matter (PM)
- Nitrogen oxide (NOx)
- Carbon monoxide (CO)
- Hydrocarbons (HC)
- Additional hazardous air pollutants (HAPs)
Some of these also contribute to ground-level ozone pollution, known as smog. These particles can also lead to an increase in acid rain.
As far as human health, these contribute to:
- Heart disease
- Lung disease
- Allergic reactions
- Asthma
- And more
Finally, these pollutants damage plants and other agricultural crops. They have also been known to contaminate water resources and do harm to animals.
For this reason, the EPA is strict with diesel regulations. The federal government continues to work toward ensuring the environment remains as clean as possible.
FAQs.
Q: Does diesel fuel have a color?
Yes, diesel fuel comes in 3 different varieties, which include; red, blue, and clear. The colors differentiate the diesel fuel based on the United States government’s regulation for the varieties of diesel sold in gas stations.
It is essential to understand the difference that exists among these three varieties of diesel fuel and the tax, as well as the legal implications of purchasing them.
Using substances that have dangerous impacts when not properly handled can be very disastrous, hence the need for the government to guard citizens and residents against their use.
If you drive a car with a diesel engine, kindly find out the implication of using the kind of diesel fuel you regularly use to prevent unexpected implications.
Q: What color is diesel naturally?
Diesel comes naturally white, clear, or slightly amber. It does not include any form of pigment or dye. In other words, the coloration in diesel is due to the additives that manufacturers include in the production process.
Various manufacturers of diesel add different kinds and quantities of sulfur to diesel fuel in the manufacturing process. That means there are tendencies for some manufacturers to add more sulfur to their diesel fuel than others.
It is crucial to know the natural color of diesel in order to be able to spot diesel fuel that has been excessively mixed with additives, especially to the point that it can be harmful to its users.
Q: How can you tell if fuel is diesel?
Knowing the type of fuel your vehicle is designed to use will help you avoid unnecessary challenges that come with using the wrong fuel. It is pretty easy to know if fuel is diesel or not.
In order to ascertain whether a car has been fashioned to use diesel fuel, open the door that grants access to the fuel tank. Kindly check out the release button or level that unlocks the fuel door and engage any of them to open.
After that, look within the space, you will find a label with the words “Unleaded Gasoline Only” or “Diesel Fuel Only.” It can also be any other short write-up that lets you know the type of fuel to use on the vehicle. Also, note that there are different types of diesel engines.
Q: Is diesel supposed to be clear?
Sure, diesel can be clear. If you are asking, “How many types of diesel fuel are there?” Diesel comes in different varieties, and they include – clear, blue, and red.
Clear diesel is the variety that does not include any dye additive. It is a road-grade fuel used by most vehicles with diesel engines.
Clear diesel fuel is available and sold in virtually all gas stations across the streets in every city or neighborhood. If you drive a car with a diesel engine, make sure to use clear diesel as it is the designated diesel fuel for most diesel engines.
Q: What kind of fuel is diesel?
Diesel is a combustible liquid that is manufactured from crude oil and refined for use in diesel engines. The fractions of crude oil that make up diesel are relatively less volatile compared to the fractions that make up gasoline.
Diesel fuel is popularly referred to as diesel oil. Vehicles with diesel engines are powered by diesel fuel only. Any attempt to use any other fuel in the engines can damage the engine completely.
If you drive a car with a diesel engine, you must stick to using diesel fuel no matter what because any other fuel like gasoline can be detrimental to the engine.
Q: What does yellow diesel mean?
Yellow diesel means the diesel fuel has been altered from its original state. Diesel comprises 3 basic varieties, and they are – clear, blue, and red.
Usually, when diesel is refined, the manufacturers add a green dye to the mixture, which adds a noticeable color to the substance.
The green dye is subject to fading; hence when diesel is newly refined and dispensed into a clear bottle, the green dye reveals its color. However, when the diesel fuel starts aging, the dye begins to fade until it changes to yellow or something darker.
So, if you find yellow diesel fuel, it is a sign that the fuel has stayed more than necessary without being used, hence the alteration in its color.
Q: Is green diesel illegal?
Of course, green diesel is illegal. The government taxes this kind of diesel fuel at a reduced rate because of their specific purposes such as agriculture.
In order to differentiate this kind of diesel fuel, a green dye is added. That is why they are also known as “marked gas oil – MGO.”
Green diesel fuel is chemically marked to deter people from misusing the fuel for any other purposes other than the purpose it has been marked (e.g., agriculture).
Drivers who have stubbornly disobeyed the regulations that guard against the use of green diesel have faced severe consequences, including fines running into thousands of dollars.
Q: Is Red diesel illegal?
Yes, red diesel is entirely illegal for on-road vehicles. The government does not tax red diesel fuel like clear diesel and gasoline because they are exclusively used in off-road equipment.
However, the federal government and the state governments have strict rules and regulations that vehicle owners must comply with in order to use red diesel fuel in on-road vehicles.
Distributors and retailers of crude oil products are strictly under monitoring to ensure that they do not sell red diesel to users who intend to use them in on-road vehicles with diesel engines.
Ensure to find out the types of diesel fuel for cars and stick to the most suitable for your vehicle.
Q: Is Red diesel the same as green diesel?
No, red diesel is not the same as green diesel. They differ in terms of their compositions, colors, and uses. You may want to check out the diesel fuel properties of red diesel for further understanding.
Red diesel is not subject to federal taxes, and they are produced for off-road equipment. It can also be used as heating oil.
On the other hand, the term “green” in green diesel typically refers to the animal fats and plant components used in manufacturing the diesel fuel. They do not also attract the same tax level as regular diesel fuel and gasoline.
Final Words
The various types and colors of diesel fuel have in-depth exposure in the article above to enable you to differentiate them appropriately.
If you have anyone who’s asking, “What color is diesel fuel?” Kindly educate them so that they can also take an informed decisions when needed.
Meanwhile, don’t forget that on-road vehicles are expected to use clear diesel fuel. Therefore, it is crucial to refrain from using green or red diesel fuel for any other purposes except for the right purpose.