What happens when you put diesel in a gas car and vice versa?

Nobody’s perfect, and sometimes that means accidentally putting the wrong fuel in your car. If you have multiple cars with different fuel types and switch between them, the chances of accidentally using the wrong fuel increase. Some things can be substituted without much thought, like using a different brand of batteries in your remote. However, fuel is a different story. 

Diesel and gasoline cannot be used interchangeably. Unfortunately, this mistake can damage your car and cost a lot to fix. It’s a mistake that can happen to anyone, but the good news is it’s fixable if you handle it the right way. 

Gasoline and diesel are both used to power vehicles, but they function very differently in engines. Diesel engines rely on diesel as a lubricant for engine components, which means that diesel reduces friction and helps keep the engine parts working smoothly. If gasoline is mistakenly added to a diesel engine, it lacks this lubricating property, resulting in increased friction between components. Over time, this can cause massive wear and tear or even severe damage to the engine.

On the other hand, diesel fuel in a gasoline engine creates different problems. Gasoline engines require spark plugs to ignite the fuel, while diesel engines depend on high compression to ignite the fuel. Diesel fuel does not vaporize in the same way as gasoline, so it won’t ignite properly in a gasoline engine, which can lead to clogging in the fuel system, preventing the engine from running correctly. If any gasoline remains in the fuel lines, the engine might run briefly, but it will stall once the leftover gasoline is used up.

If you notice that you’ve pumped the wrong fuel into your car but haven’t started the engine yet, the best thing to do is to stay calm and avoid turning the key. Starting the car will mix the wrong fuel with the fuel already in the system, which can cause severe damage to parts like the fuel pump and injectors. Immediately take the key out of the ignition and prevent anyone else from attempting to start the vehicle.

Next, inform the gas station attendant about the situation. Many gas stations have the tools or a service bay where they can help you safely drain the wrong fuel. If the station doesn’t have these facilities, ask the attendant to assist you in moving the car to a safe area within the station’s premises while you arrange for professional help. In cases like these, you have to act quickly but carefully to minimize any damage.

If you’ve already started driving and realize the mistake, maybe due to unusual noises, engine stalling, or poor performance, pull over immediately. Look for a safe place, such as the shoulder of the road or a parking lot, and stop the car. Continuing to drive with the wrong fuel can lead to more serious problems, such as clogging the fuel system or damaging the engine’s internal components.

The problem is worse if you put gasoline in a diesel engine, as gasoline ignites much more easily than diesel. This can result in pre-ignition causing catastrophic damage to the engine. Meanwhile, putting diesel in a gas engine won’t result in as much damage, but will ruin components like your fuel filter, and possibly even your fuel pump. 

Once you’re safely stopped, turn off the engine and take the key out of the ignition. At this point, driving further is not an option. Call for assistance and avoid attempting to restart the car, as this can worsen the issue. Keeping the engine off limits the potential damage while you wait for help to arrive.

When your car is safely stopped, the next step is to call a tow service. Towing guarantees that your car can be transported without risking further damage to the engine or fuel system. If you’re not sure which towing service to call, ask the gas station or roadside assistance provider for recommendations. Be prepared to share your car’s location and the nature of the problem so the towing team knows how to handle the situation.

After your car has been towed, contact a trusted mechanic or a service center. Draining the wrong fuel from your car is a process that requires specific tools and expertise. The mechanic will remove the fuel, clean the fuel lines, and inspect for any damage caused by the mistake. Depending on the severity, this process can take a few hours, and in rare cases, additional repairs may be needed.

To avoid misfueling in the future, take simple precautions that act as reminders. For example, label the fuel cap of each car with the type of fuel it requires, or place a sticker on the dashboard. If you own multiple cars with different fuel types, consider labeling your car keys as well. These small reminders can help you double-check before pumping fuel.

Additionally, make it a habit to confirm the fuel type with the gas station attendant before refueling, which is especially useful if you’re in a hurry or distracted. These simple steps can save you the time, money, and stress of dealing with a misfueling incident. Prevention is always better than fixing a costly mistake.

Mistakenly putting diesel into a gasoline car or finding diesel mixed with your gasoline doesn’t have to ruin your day. It's not the end of the world! The most important thing is to avoid starting the engine. Call for a tow and get your car to a repair shop where they can drain the tank and so no further damage occurs. When it’s time to shop for a new car, visit AutoDeal.com.ph for a complete list of models available in the Philippines, so you can find your next ride easily and conveniently.