What Happens if You Put Diesel in a Gas Car? ~ Lets Find Out

Have you ever wondered what would happen if you accidentally filled up your gasoline-powered car with diesel?

It may seem like a harmless mistake, but the consequences can be significant.

In this article, we will explore the effects of putting diesel fuel into a gas car and discuss the steps you should take if such an incident occurs.

Understanding Diesel and Gasoline

To comprehend the repercussions of mixing diesel and gasoline, it’s important to understand the fundamental differences between the two fuels.

Properties of Diesel

Diesel fuel, commonly used in diesel engines, is characterized by its higher energy density and viscosity compared to gasoline.

It contains hydrocarbons that require higher compression ratios for ignition. Additionally, diesel fuel has lubricating properties that are beneficial for diesel engines.

Properties of Gasoline

Gasoline, on the other hand, is a lighter and more volatile fuel commonly used in gasoline engines.

It ignites at lower temperatures and has a lower energy density compared to diesel. Gasoline also lacks the lubricating properties found in diesel fuel.

The Impact of Putting Diesel in a Gas Car

What Happens if You Put Diesel in a Gas Car

Accidentally putting diesel fuel into a gas car can have several detrimental effects on both the vehicle’s performance and its components.

Fuel System Damage

Gasoline engines have fuel systems specifically designed for the properties of gasoline. When diesel is introduced into this system, it can cause damage.

Diesel has a higher viscosity, which can clog fuel injectors and filters, impeding the flow of fuel. The accumulation of diesel residue can lead to decreased engine performance and potentially expensive repairs.

Engine Performance Issues

Diesel requires higher compression ratios for combustion, which gasoline engines are not designed to accommodate.

As a result, the engine may struggle to ignite the fuel properly, leading to rough idling, reduced power output, and increased emissions.

Continued use of the contaminated fuel can cause long-term damage to the engine.

Potential Safety Risks

Mixing diesel with gasoline can also pose safety risks. Since diesel has a higher flash point than gasoline, the risk of fire or explosion increases if the fuel mixture reaches hot engine components.

Moreover, the incorrect fuel blend can cause engine misfires or sudden shutdowns, compromising the vehicle’s maneuverability and potentially leading to hazardous situations on the road.

Steps to Take if Diesel is Accidentally Added

If you find yourself in the unfortunate situation of having added diesel fuel to your gas car, here are some steps to mitigate the damage:

Immediate Actions

  1. Do not start the engine: Starting the engine will circulate the diesel fuel further into the system, potentially causing more damage.
  2. Tow the vehicle: If possible, have the car towed to a safe location away from traffic.

Professional Assistance

  1. Contact a mechanic: Seek professional assistance from a qualified mechanic or automotive technician. They will be able to assess the extent of the damage and provide guidance on the necessary repairs.
  2. Drain the fuel system: The mechanic will likely need to drain the entire fuel system, including the fuel tank, lines, and injectors, to remove the diesel fuel completely.

Preventive Measures

  1. Label the fuel cap: To avoid future mishaps, consider labeling the fuel cap with a reminder of the correct fuel type for your car.
  2. Double-check before fueling: Take a moment to double-check the fuel pump and nozzle to ensure you are using the correct fuel type.


In conclusion, putting diesel in a gas car can have severe consequences for the vehicle’s fuel system, engine performance, and safety.

It is crucial to take immediate action, seek professional assistance, and be diligent in preventing such incidents from happening again.

Remember to always double-check before fueling your car and consult a mechanic if you accidentally use the wrong fuel.


Q1: Can I mix a small amount of diesel with gasoline in a gas car?

No, even a small amount of diesel can cause damage to a gas car’s fuel system and engine. It is best to avoid any mixing of fuels.

Q2: How can I prevent accidentally putting diesel in a gas car?

To prevent such accidents, always double-check the fuel pump and nozzle before fueling your car. Consider labeling the fuel cap with a reminder of the correct fuel type.

Q3: Can diesel fuel damage my gas car’s engine permanently?

Continued use of diesel fuel in a gas car can lead to long-term damage to the engine. It is essential to have the fuel system drained and seek professional assistance as soon as possible.

Q4: Will my car insurance cover the repairs if I put diesel in a gas car?

Car insurance policies vary, but most do not cover damage resulting from the use of incorrect fuel. Check with your insurance provider to understand your coverage.

Q5: Is it safe to drive the car after putting diesel in a gas car?

It is not recommended to drive the car after adding diesel to a gas car. Have the vehicle towed to a safe location and seek professional assistance to avoid further damage and potential safety risks.

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