What Happens If You Put Diesel in a Gas Car

Fueling your vehicle seems like a straightforward task, but it’s surprisingly easy to make a mistake at the pump. One of the most common errors is accidentally putting diesel fuel into a gasoline car. Understanding the consequences of this mistake and knowing what steps to take can save you from costly repairs and significant inconvenience.

Understanding the Difference Between Gasoline and Diesel

Gasoline and diesel are both fuels derived from crude oil, but they have distinct properties and are designed for different types of engines. Gasoline is a volatile, refined product intended for spark-ignited internal combustion engines. It burns quickly and is optimized for the higher revving of gasoline engines.

Diesel, on the other hand, is less refined and has a higher energy content per gallon. Diesel engines use compression to ignite the fuel rather than spark plugs, making them more efficient for heavy-duty tasks and long-haul driving. Because of these differences, gasoline engines require gasoline, and diesel engines require diesel.

Immediate Effects on the Vehicle

When diesel fuel is pumped into a gasoline engine, several immediate symptoms can occur. These symptoms are often noticeable even before you start the engine.

Engine Misfiring: Diesel does not ignite in a gasoline engine as it should. This can cause the engine to misfire or fail to start altogether.
Difficulty Starting the Car: The engine may struggle to start or may not start at all. This is because diesel is less volatile and does not vaporize easily at low temperatures, which is essential for a gasoline engine to function.
Excessive Smoke from the Exhaust: If the car does start, you may notice thick, black smoke coming from the exhaust. This is unburned diesel fuel exiting the exhaust system.
Unusual Engine Noises: The car may make strange knocking or pinging sounds due to improper combustion of the diesel fuel.

Diesel in a gasoline engine affects the fuel system almost immediately. Diesel fuel is thicker and more lubricating than gasoline, leading to issues with the fuel injectors, fuel pump, and fuel filter.

Long-term Damage

Using diesel in a gasoline car can lead to severe and costly damage if not addressed promptly. The long-term effects include:

Damage to Engine Components: The engine’s spark plugs, designed for the quick ignition of gasoline, may become fouled or damaged by diesel. This can lead to misfires and engine failure.
Catalytic Converter Issues: Diesel can damage the catalytic converter, an essential part of the exhaust system that reduces harmful emissions. Repairing or replacing a catalytic converter can be very expensive.
Exhaust System Damage: The exhaust system can become clogged with unburned diesel, leading to further engine performance issues and potentially necessitating a complete exhaust system replacement.

In summary, diesel can compromise the performance and lifespan of your gasoline vehicle.

Driving Hazards and Safety Risks

Driving with diesel in a gasoline car not only endangers your vehicle but also poses significant risks to others on the road.

Immediate Vehicle Malfunction: A gasoline engine running on diesel can lead to engine misfiring, stalling, or a complete shutdown. An injury attorney relayed that such sudden mechanical failures can result in loss of vehicle control, particularly dangerous at high speeds or in heavy traffic.
Loss of Power: If your car suddenly loses power or stalls, it can cause you to lose control of the vehicle, especially at high speeds. This can result in an accident, putting you and other motorists at risk.
Unexpected Stops: Stalling in the middle of traffic, especially on highways or busy roads, can lead to rear-end collisions or multi-car pile-ups as other drivers may not have enough time to react.
Reduced Visibility: Thick, black smoke from the exhaust can obscure the vision of drivers behind you, creating hazardous driving conditions.
Environmental Hazard: Besides visibility issues, the smoke contains harmful pollutants, contributing to environmental pollution and potentially causing health issues for nearby pedestrians and drivers.

If you ever find yourself stranded in a hazardous location, use hazard lights and reflective triangles to alert other drivers.

Steps to Take If You Accidentally Put Diesel in a Gas Car

If you realize your mistake before starting the car, do not start the engine. Contact a professional mechanic or roadside assistance immediately. Here are the recommended steps to follow:

Do Not Start the Car: Starting the engine will circulate diesel through the fuel system, causing more damage.
Contact Professional Help: Call a mechanic or a towing service to have your vehicle transported to a service center.
Draining the Fuel Tank: The mechanic will need to drain the fuel tank and thoroughly clean the fuel system to remove all traces of diesel.
Inspection and Repair: The fuel injectors, fuel pump, fuel filter, and other components may need to be inspected and potentially replaced. This ensures that any diesel residue is removed and that your vehicle can function correctly again.

Prevention Tips

Preventing such a mistake is relatively simple if you take a few precautions:

Double-check Fuel Type Before Refueling: Always confirm the type of fuel required by your vehicle and the type of fuel you are about to pump.
Pay Attention to Fuel Pump Labels: Fuel pumps are clearly labeled. Take a moment to verify you are using the correct nozzle.
Educate Family Members and Frequent Drivers: Ensure that anyone who drives your vehicle is aware of the correct fuel type.
Use Labeled Fuel Caps: Consider using a fuel cap with a label indicating the correct fuel type to serve as a reminder.

Putting diesel in a gas car can cause significant damage and inconvenience. Understanding the differences between gasoline and diesel, recognizing the symptoms of this mistake, and knowing the appropriate steps to take can save you time and money. If you ever find yourself in this situation, seek professional help.