A Comprehensive Guide to Mixing Red and Regular Diesel Fuels

Diesel fuel

Diesel fuel is one of the most commonly used fuels in the UK. It powers various vehicles and machinery, from cars and trucks to generators and construction equipment. Red diesel is often used in off-road vehicles and machinery, while normal diesel is used in on-road vehicles. But what happens if you mix the two? This article will discuss whether mixing red and normal diesel is safe.

What is Red Diesel?

Red diesel is a type of diesel fuel that is dyed red to distinguish it from normal diesel. It is also known as gas oil or tractor diesel. Red diesel is typically used in off-road vehicles and machinery, such as tractors, excavators, and generators. It is also used in boats and other marine equipment. The red dye makes it easy for authorities to distinguish between vehicles that use red diesel and those that use normal diesel.

What is Normal Diesel?

Normal diesel is used in on-road vehicles such as cars, trucks, and buses. Normal diesel is not dyed and is subject to a higher level of taxation than red diesel. This is because it is used on public roads and highways, which puts wear and tear on the streets and requires maintenance and repairs.

Can You Mix Red Diesel and Normal Diesel?

The short answer is that you can mix red and normal diesel. However, it is not recommended. This is because red and normal diesel have different properties, and mixing them can affect your vehicle’s or machinery’s performance and efficiency.

The high Sulfur content in red diesel can cause damage to the engine and exhaust system, particularly in vehicles designed to run on low or ultra-low-sulphur diesel. Mixing red diesel with normal diesel can also lead to increased emissions, which are harmful to the environment and may not comply with emissions regulations.

Effects of Mixing Red Diesel and Normal Diesel

When you mix red and normal diesel, the resulting mixture will have a lower cetane rating than normal diesel. Cetane rating is a measure of the fuel’s ignition quality. The higher the cetane rating, the easier it is to ignite the fuel. Lower cetane ratings can lead to decreased engine performance, increased emissions, and increased wear and tear on the engine.

Another effect of mixing red diesel and normal diesel is that it can cause problems with the fuel system. The red dye in red diesel can clog filters and injectors, reducing fuel flow and engine performance.

What to Do If You Accidentally Mix Red Diesel and Normal Diesel

If you accidentally mix red diesel and normal diesel, you should first stop using the mixture. Drain the fuel tank and dispose of the mixture properly. You may need to replace filters and injectors to prevent any damage to the fuel system.


You must know the differences between red diesel and normal diesel, as mixing them can cause potential damage to your engine and fuel system. Remember, prevention is always better than cure. Be cautious when refuelling your vehicle or equipment; always use the correct fuel type. If unsure, consult your vehicle’s manual or a professional for guidance.

Are you stuck with red diesel in your vehicle? Don’t worry – Fuel Fixer is here to save the day! Our expert technicians will quickly and efficiently remove the red diesel and get your engine running smoothly again. Contact us today for immediate assistance!

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