Petrol in a Diesel Car Symptoms & Solutions

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You are in hurry and realise that you have to refuel your car, you are driving to the closest fuel station and refuelling your car as fast as you can. You jump inside your car again and continuing your driving, your car starts to jerk a bit and you start to think “Did I really fill diesel in my diesel car, or was it the green pump?”, “What will happen now”? There are a lot of questions in your head at this moment but do not worry.


In this article, you will learn about the most common symptoms and what could happen if you fill petrol in a diesel car.


Petrol in diesel carCheck Engine Light

Knocking sound from engine

Rough Idle & Acceleration

Engine stops & won't start
Shut off your engine

Tow home or to a workshop
Empty the fuel tank of petrol and replace the fuel filter. Refill with diesel.


Petrol in a Diesel Car Symptoms

Because the patrol and the diesel are two completely different fuel types, you can get a lot of symptoms when you have petrol in your diesel car. Here is a list of the most common symptoms you do normally get after you fill your diesel engine with petrol.

The most common symptoms of petrol in diesel cars are knocking sounds from the engine, rough idle & acceleration, engine warning light and the engine may stop and won’t start again. Never drive your car with petrol in the diesel tank. Shut off your engine as fast as possible and tow it to a car repair workshop or to your home. Empty the petrol from the tank and replace the fuel filter and fill it up with diesel again.

Check Engine Light

Because modern car engines are very smart, it does often recognize when you have filled petrol in your diesel engine. This will often result in a check engine or a service engine soon light on your car’s dashboard.

Knocking Sound from Engine

Because the petrol is a lot more flammable than the diesel fuel, you can often get a loud “knocking” noise from your engine which has not been there before. If you have only filled a little petrol in your diesel tank, you may not experience the knocking sound, but it’s a good sign to look for if you suspect that you refuelled with petrol.

Rough Idle & Acceleration

You can often experience a Rough idle and a rough acceleration when you have refuelled your diesel tank with petrol. This is because the engine is designed to run perfectly with the diesel fuel and the diesel and petrol fuel are two very different fuel types.

Engine stops & Won’t start

In many cases, if you have refuelled with a lot of petrol in your empty diesel tank, your engine may stop and be impossible to start again. If this is the case it could lead to very expensive repairs if you are unlucky.


Can my diesel car get damaged by petrol in the fuel tank?

Yes, a lot of parts can get damaged if you have too much petrol in your diesel tank. In many cases, where you have a half tank diesel and refill just a bit of petrol, it will probably not make a lot of damages. But because you do often drive to the fuel station with an empty diesel tank and refuelling it full of petrol, it can cause serious damages to your engine and result in very expensive repair costs.

Because the petrol does not have the same lubricating properties as the diesel fuel, it can cause serious damages to your diesel pump fast. A faulty diesel pump can result in metal chips getting loose and it will fill your whole fuel system with it. If this is the case you do often have to replace the whole fuel system including the hoses and fuel lines.

It can also cause damages to your internal parts in the engine like the pistons if you are very unlucky. This is pretty rare and the most common thing to get damaged is the diesel pump which results in metal chips all over the fuel system.


What to do if I have petrol in my diesel car?

If you think that you have petrol in your diesel tank, the first thing you should do is to stop your car in a safe spot and shut off your engine as fast as possible. If you stand at the fuel station and haven’t started your engine before you realise that you filled it with the wrong fuel, Do not start the car!

Tow the car to a car repair workshop or to your home. Empty the gasoline from the tank either with a Fuel Hand pump or with the use of the inbuilt prime pump inside the tank. If you have a prime pump in the tank, you can lose the fuel pressure line and recycle the ignition to get the fuel out.

After you have got all the petrol out of the tank, replace the fuel filter and fill the tank with diesel again. Then start your car and try again, in many cars you have to bleed the diesel fuel system before you will be able to start it.

By following these steps, you may be able to save the engine and it works in 90% of the cases. In some cases, if you have driven too far with too much petrol in the tank, your diesel pump could have been damaged and it may result in a replacement of the whole fuel system because the pump will fill it with metal chips.


Petrol and Diesel are two completely different fuel types, and you can get a lot of strange symptoms if you have petrol in a diesel car

If you realise that you filled it with petrol, stop your car at a safe spot and shut off the engine and tow it to a workshop

If you realise at the fuel station that you are refuelling with the wrong fuel, do not start your car. Tow it to a workshop.

Petrol in a diesel car can result in damages to your diesel pump, which can fill up the fuel system with metal chips and damage the whole fuel system. It can result in repair costs above 10.000$


If you have any questions or want to tell us your story of how you solved this problem, comment down below. If you have any other car questions you are welcome to ask them at our homepage.


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