What fuel for a diesel car?

What fuel for a diesel car? Gasoline or gasoil? Discover which fuel you should choose for your diesel engine depending on your vehicle type.

Choosing the right fuel for your vehicle might seem straightforward, but when it comes to a diesel engine, the question deserves special attention. Can you really use gasoline in a diesel car? What’s the difference between gasoline and diesel fuel? And most importantly, what happens if you make a mistake at the pump? In this article, the fleet management experts at hitech break down the specifics of diesel fuel, the risks of using the wrong type, how to recognize different fuel options at the pump, and the environmental impacts you need to consider.

What gasoline for a diesel engine?

What gasoline for a diesel engine is a common question, but in reality, no type of gasoline is suitable for a diesel engine. A diesel car must strictly be fueled with diesel, the only type of fuel designed for this kind of engine. Using gasoline in a diesel engine can cause serious mechanical damage.

What’s the difference between gasoline and diesel?

The difference between gasoline and diesel lies mainly in their chemical composition, combustion process, and intended use. Gasoline is more volatile and ignites with a spark in a spark-ignition engine. Diesel (or gasoil), on the other hand, ignites through compression in a compression-ignition engine. The question “diesel car, what gasoline?” reflects a common confusion and highlights the importance of understanding the technical specifics of each engine type to avoid mistakes.

Gasoline-powered vehicles typically use SP95, SP98, or SP95-E10 for newer engines. Diesel engines, on the other hand, run exclusively on diesel fuel, sometimes blended with biofuels like biodiesel. This means different engines, different performance characteristics, and different maintenance requirements. Diesel engines usually offer more torque and better fuel efficiency over long distances, while gasoline engines are often preferred for short trips and urban driving.

What happens if you put gasoline in a diesel car?

Putting gasoline in a diesel car is a common mistake, but one that can have serious consequences. Gasoline lacks the lubricating properties of diesel and can damage the fuel injection pump, injectors, and other engine components. If only a small amount is added, the vehicle might still run for a short time, but the risk of breakdown is high. If you realize you’ve made this mistake while refueling, it’s crucial not to start the engine and to call a professional immediately to drain the tank. This can help prevent major damage to the engine and fuel system.

How to recognize diesel or gasoline?

To make it easier to identify diesel or gasoline at the pump, a standardized European labeling system has been in place since October 12, 2018. Introduced through the AFID (Alternative Fuel Infrastructure Directive), this system helps drivers choose the right fuel using simple visual symbols:

• A geometric shape: a circle for gasoline, a square for diesel.
• A letter: E for gasoline (e.g., E5, E10), B for diesel (e.g., B7, B10).
• A number: indicating the percentage of biofuel in the fuel.

These labels are displayed both on fuel pumps and on newer vehicles to help prevent refueling mistakes.

What is the impact of a diesel car?

The impact of a diesel car raises many questions, both environmentally and economically. While diesel engines typically emit less CO₂ than gasoline engines over the same distance, they release more nitrogen oxides (NOx) and fine particles, which contribute to air pollution. These emissions have led to restrictions in certain urban areas and changes in mobility policies. For better fleet management, these issues are central to strategic decision-making—particularly when preparing a shift toward more sustainable solutions.

How to choose the right fuel?

Knowing how to choose the right fuel for your vehicle is essential to avoid misfuelling and to ensure optimal engine performance. Here are some simple guidelines to help you avoid mistakes—whether you’re behind the wheel of your own car, a company vehicle, or a rental:

• Check the label on the vehicle: The indication “gasoline” or “diesel” is usually found inside the fuel flap or on the fuel cap.
• Look for rental car stickers: Rental companies often place visible reminders on the windshield, dashboard, sun visor, or key. The fuel type is also listed in the rental agreement.
• Know the model name: Diesel vehicles often include a “D” in the name, such as TDI, HDI, or DCI.
• Check the pump nozzle size: Diesel nozzles are wider and typically don’t fit into gasoline tanks. However, gasoline nozzles can fit into diesel tanks, which is why extra attention is needed.

In a business context, proper fuel management is a major concern for fleet managers and rental companies. This is especially true since fuel can represent 15% to 30% of total fleet costs. The myrentcar fleet management software includes integrated fuel card tracking to monitor expenses by vehicle or driver. It also helps detect consumption anomalies. Additionally, myrentcar offers cost management tools to help identify areas for optimization and improve overall fleet profitability. You can explore all the features of myrentcar on our dedicated fleet management blog.