Getting fuel types mixed up at the pump could result in major engine problems. But some mix-ups cause more damage than others, so here are some specifics on how the wrong fuel can affect certain engines.

What happens when gasoline goes into a diesel engine?

Putting gasoline into your diesel engine could produce catastrophic results for your engine and its parts, according to J.D. Power. If you mistakenly fill your diesel engine with gasoline, do not start the engine. Your vehicle will need to be towed to a repair shop or facility who can drain the tank and advise of next steps.

This is because diesel engines ignite fuel using the heat created when the fuel is compressed by the engine piston, according to the U.S. Department of Energy (DOE). This is unlike gasoline engines, which use spark plugs to ignite the fuel.

Compression ratios for diesel engines are typically 16:1 or higher. On the other hand, gasoline engines usually have a compression ratio of 9:1 or 10:1, according to Engine Builder Magazine. This difference in compression ratios causes gasoline to have higher combustion tendencies than diesel.

What if you put diesel into a gasoline engine?

Mistakenly filling up a gas-fueled car with diesel may not ruin your engine, but it could ruin other parts of your fuel system, like your fuel injectors or your fuel pump, according to J.D. Power. That's because diesel is thicker and denser than gasoline, which makes it difficult for the fuel pump to move it through the system. Eventually, any diesel fuel that makes its way to the engine will quickly clog up the fuel injectors.

Rather than running the engine, have your car towed to a professional who can ensure the fuel system is drained and cleaned.

What if I put E85 in a vehicle not made for it?

According to the Department of Energy, most gasoline in the U.S. contains ethanol. Traditional unleaded fuel typically contains a ratio of 10 percent ethanol to 90 percent gasoline. However, flex-fuel vehicles are designed to run on E85, which has a ratio of roughly 85 percent ethanol to 15 percent gasoline.

If your car isn't a flex-fuel vehicle and you mistakenly add E85 to your tank, you may notice reduced performance and gas mileage. Your check engine light may also appear, but the mishap likely won't damage the engine. They recommend topping the tank off with regular gasoline several times. When all the E85 has cycled through the engine, the check engine light should turn off.