What Happens When You Accidentally Add Diesel to a Gasoline Car?

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Diesel in a gas tank or gas in a diesel tank; either way it's not great news. Here are step-by-step instructions on how to deal with using the wrong fuel.

Ever wondered what happens if you put diesel in a gas engine? In short, it could cause serious damage—especially if you compound the mistake by starting the car after filling up. The good news is, it’s unlikely to ever happen to you, as diesel pump nozzles are too large to fit into standard gas tanks. However, if you ever find yourself in this situation, follow these step-by-step instructions.

If you fill the tank with the wrong kind of fuel and HAVE NOT started the engine:

1. Don’t start the engine.
2. Tell a gas station attendant what’s happened.
3. Ask someone to help you push your car out of the way.
4. Call a towing company so they can tow your car to a mechanic who will drain the fuel.
5. If the fuel hasn’t been drawn into the engine, you may get away with no damage at all.

If you HAVE started the engine:

Things may be more difficult if you’ve driven the car, as the wrong fuel can damage your engine if it’s drawn through the system. Don’t start it again unless you have to, for example, if you’re in an unsafe position and have no one to help you push your car.

1. Make sure you’re parked in a safe place.
2. Make sure your ignition is off.
3. Call your mechanic and the towing company.
4. Call your insurer.
5. A mechanic will need to drain your tank of fuel and you’ll probably need the filter replaced to protect your engine.

How it will affect your insurance:

Filling up with the wrong fuel is often classed as accidental damage with a comprehensive insurance policy. However, you need to check with your insurer whether they’ll cover roadside assistance and fuel removal.

Now that you know what happens if you put diesel in a gas engine, find out what these strange car noises could mean.