Dyed vs. Regular Diesel and the Different Diesel Fuel Grades

October 25, 2023

Getting the most for your money is a common priority. Diesel fuel is often used in fields like construction, trucking and agriculture. Selecting the right type and grade will prolong equipment life while saving you money.  

Consider this your guide to red and traditional diesel as well as diesel #1 and #2 fuel grades.


About Regular Diesel

Regular or traditional diesel refers to petroleum diesel fuel, which is made through the distillation of crude oil, where it is transformed into liquid form. Plenty of vehicles, boats and aircraft use petroleum diesel, including semi-trucks, jets, trains and charter buses.

Petroleum diesel sees regular use in the construction and agriculture industries. The U.S. military also depends on traditional diesel to power tanks, as the fuel is less flammable than gasoline. Generally, diesel fuel is safer for the environment than gasoline since combustion releases fewer toxic emissions.


What About Green Diesel?

When you’re buying fuel, you may see liquid diesel with a green tint to it. This dye indicates that you can use the fuel for on-road use, including government-owned highways. Green diesel is taxed, making it appropriate for personal and commercial vehicles.

The term “green diesel” is sometimes used to reference renewable or biodiesel. Speak with a diesel supplier before purchasing for transparency about the fuel you’ll receive.


What Is Red-Dyed Diesel?

Red diesel is a fuel type used by the construction and agriculture industries. The fuel powers heavy equipment and off-road vehicles such as excavators, dump trucks and tractors. Unlike traditional diesel fuel, red diesel fuel is for off-road use only, making it illegal for use with pickup and commercial trucks.

If you’ll be driving on road systems constructed using tax dollars, traditional or green diesel is the legal to go.

Top Uses of Red Diesel

Those in the construction world rely on red diesel to power hard-working machines such as bulldozers, backhoes, wheel loaders, cranes and emergency generators.

Farmers use red diesel for plows, harvesters, mowers, balers and spreaders. Other industries taking advantage of red diesel include the boating and rail transport fields.

Characteristics of Red Diesel

Red diesel is identifiable by its shade. This fuel is dyed red so that it can be allocated by governing bodies for tax purposes. Officials can better regulate and determine where the fuel is going. 

For example, red diesel supplies might be designated for the marine industry versus regular diesel intended for the automobile industry. Red and traditional diesel are priced differently because of taxes, so the fuel’s coloration streamlines shipping procedures. Other than its shade, red diesel has the same chemical characteristics as regular diesel fuel.

At What Point Is Red Diesel Dyed?

The red dye diesel that professionals use for work changes color before transportation to a fuel distributor. Dying the fuel makes it easier to identify by sight — this streamlines the process of deciding which fuel supplies need to be taxed versus which are tax-free at the time of sale.

Those who regulate fuel supplies can detect the color of diesel using a black light. Even if fuel has been used, this light picks up any residuals in a tank.


Red Diesel Goes by Several Names

These terms are industry names for red diesel:

  • Untaxed diesel fuel
  • Tax-free diesel fuel
  • Red-dyed diesel fuel
  • Off-road diesel fuel
  • Farm diesel fuel


Storing Traditional and Red Diesel

It’s safe to store diesel fuels for roughly two months without further treatment. The main concern with long-term diesel storage is moisture or dirt entering the mixture via tank vents.

Professionals should use fuel additives when storing diesel fuel for longer than a month. The right additive will help you avoid algae and bacteria. EDT and EDT+ Winter Defense not only add cetane and lubricity but also aids in diesel tank maintenance to prevent algae from forming.


Red Diesel and Changing Temperatures

You must treat red diesel to prepare for cold temperatures. Diesel fuel is subject to gelling — parts of the mixture crystallize and separate from the fuel. This process can lead to engine filter clogging. Treating red diesel is a good idea when temperatures dip below 20 degrees Fahrenheit. EDT+ Winter Defense prevents fuel gelling down to -65 degrees Fahrenheit. 


Red Diesel vs. Regular Diesel

Key differences between red diesel and traditional diesel are as follows:

  • Visual identification: You can tell the difference between diesel fuels based on whether the fuel appears red, clear, green or yellow.
  • Taxation: Entities purchasing red diesel for off-road use that falls within legal requirements can save money since it is a tax-exempt fuel.
  • Applications: You are only permitted to use red diesel for off-road applications, while regular diesel is acceptable for powering on-road and off-road vehicles.


Pros and Cons of Red Diesel

Deciding whether you’ll use red diesel requires you to balance its benefits and drawbacks.

Advantages of Red Diesel

Red diesel:

  • Offers significant cost savings.
  • Could be suitable for your industry.
  • Has great availability and accessibility in the U.S.

Disadvantages of Red Diesel

However, it:

  • Is subject to many legal restrictions and laws.
  • Can be hard to acquire when working overseas.
  • Has the potential for high-sulfur varieties to emit toxic emissions.


Pros and Cons of Regular Diesel

Staying aware of the upsides and downsides of petroleum diesel helps you make informed decisions.

Advantages of Regular Diesel

Regular diesel offers:

  • Wide availability and compatibility.
  • Compliance with regulations and standards.
  • Consistent performance.

Disadvantages of Regular Diesel

This standard fuel type also comes with:

  • Higher costs compared to red diesel.
  • Minimal tax advantages.


Diesel #1 vs. Diesel #2

While the information above settles the differences between red diesel and traditional diesel, it’s still important to understand the differences between the grades — diesel #1 and diesel #2 — to make the best choice for your vehicle and application. Note that diesel #1 and diesel #2 can be dyed, so do your research before purchasing for transparency about what grade you’re getting.


What Is the Difference Between Diesel #1 and Diesel #2?

The two fuel types have several distinguishing characteristics, including their energy content, viscosity and lubricity. Many of these distinctions lead vehicle owners to refer to diesel #1 as “premium” diesel fuel.

Energy Content

The diesel grade’s energy content impacts its fuel efficiency. Diesel #2 has more energy components and less volatility than #1. As a result, #2 typically produces better fuel economy.


Viscosity refers to the fuel’s thickness, a crucial consideration in areas with colder winters since fuel thickens at lower temperatures. Typically, diesel #1 is thinner and better resists gelling in the cold, while diesel #2 is more prone to thickening as temperatures fall. 


Diesel #2 contains higher amounts of paraffin wax than #1, which is one reason #2 has a higher viscosity. This substance provides lubrication to essential engine parts, so #2 diesel offers more friction reduction that can help extend a motor’s life span.


Benefits of Diesel #1

Benefits of diesel #1 include:

  • Cold-weather performance: The primary advantage of diesel #1 is its ability to function consistently in cold temperatures. It’s less likely to thicken and produce hard starts in wintertime.
  • Cleaner fuel systems: Diesel #1 often contains detergents to clean sediment and debris from the fuel system. Removing residual dirt also supports a longer-lasting, more powerful engine and better fuel economy.


Benefits of Diesel #2

Diesel #2 offers its own set of vehicle owner benefits, such as:

  • Higher fuel economy: Diesel #2 is less volatile and burns more slowly, providing increased energy efficiency.
  • Lower costs: Diesel #2 involves a shorter refining cycle than diesel #1, so it’s less expensive to produce and more affordable at the pump.
  • Wide availability: Diesel #2 is widely available at most gas stations because it’s the most common grade used.


About Winterized Diesel Fuel Blends

Diesel #1 and diesel #2 can be combined to provide the unique benefits of both fuel grades in cold temperatures. The combination of these fuels offers the lubrication advantages of diesel #2 alongside the low-temperature stability of diesel #1 to minimize the risk of thickening.

Consult with your owner’s manual to decide whether or not diesel fuel blends are appropriate for use in your vehicle. These mixtures can feature upwards of 20% diesel #1 fuel, which can be problematic over time for engines demanding diesel #2 only.


Which Type of Diesel Should You Choose?

There are several factors to take into consideration when choosing the ideal diesel fuel grade for your vehicle, like:

  • Vehicle type: Older or specialty engines may benefit from diesel #1’s additional properties. Your vehicle’s manual is the best source for fuel grade recommendations.
  • Driving conditions: Diesel #2 is best for trucks transporting heavy loads on regular roads due to the reduced fuel consumption. This fuel also offers slightly higher heat dissipation at payload capacity to help prevent overheating.
  • Total cost of ownership: Price differences at the pump only represent part of the equation. Vehicle owners must weigh the higher costs for diesel #1 against its potential to extend engine life and minimize downtime.
  • Local fuel quality and availability: Going out of your way to find a trustworthy station for diesel #1 is inefficient. Instead, you can consider high-quality diesel fuel additives with detergent and lubrication agents while using diesel #2.


Clean Your Diesel Fuel System With Hot Shot’s Secret

At Hot Shot’s Secret, we develop fuel additives that help you avoid major repairs. Our DIESEL EXTREME Concentrated Injector Cleaner works to lift waxy deposits that accumulate during prolonged storage. Encourage consistent startups and effectively lubricate your vehicle’s fuel system with a single solution. Improve your acceleration performance and fuel economy using a product that also disperses moisture.

Our scientifically formulated products include diesel additives, oils and lubricants to solve and prevent common automotive issues. Save money with boosted fuel economy and longer engine life spans — we stand behind our claims with a no-questions-asked refund guarantee if you’re not completely satisfied with product performance.

Need advice or have a question? Contact a Hot Shot’s Secret specialist online or call 800-341-6516.