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What Happens If You Put Diesel in Gas Engine?

Gas engine ignites with the vaporized gas, which is lighter and less oily. So, pouring diesel into the gas engine, which is oilier and heavier than the gas can, is a disaster. However, according to the fact that there are fewer possibilities of the happening of such a scenario, diesel nozzles are bigger than those of gas cars. In addition, it prevents intrusion inside the neck of the petrol nozzle (which is smaller) so that drivers don’t put the diesel in the gas engine in any case.

But, somehow, if you have poured your engine with diesel, a few things vital are there that you must know as fast as possible! Here is what happens if you put diesel in a gas car. However, you need to know what to do first!

What To Do When Putting Diesel in A Gas Car

If you are curious, or if you have already put the wrong type of gas inside, then this is for you. Here are the effects in different situations for car owners to give it a check.

What to Do When Pumping 2 Litres of Diesel Into a Petrol Car

First and the most important tip for car owners when putting the wrong type of gas in a gas engine is fuel drain. To be honest, I myself accidentally put diesel in my car, and this tip saved me. A simple fuel drain can solve most of these issues. No matter what type of gas nor the amount of contamination involved, we recommend to protect the engine by this action. However, if you just pump only 2 litres into a petrol car and just notice it afterward, there is no point to go for fuel drain.

2 litres or below this amount is way too little. To be more precise, 2 litres of diesel is unable to cause any significant damage or contamination. As a matter of fact, car owners are free to top up petrol for the remainder of the tank. The engine of your petrol vehicle should be able to run just as normal.

What to Do When Pumping Over 2 Litres of Diesel into a Petrol Engine

As we mentioned earlier, there is no problem pumping 2 litres of Diesel into a petrol engine, however, what happens when you pump more than that? In this case, the worst thing car owners could do would be to start the engine and drive. To be more specific, the gas will start flowing inside your engine, and the draining progress will be much more difficult. However, if you did not start the engine, we highly recommend to perform a complete fuel drain. It is the best thing to do in such a case.

The location of the car is always needed to keep in mind. If this happens when your automobile is around or inside the garage, car owners should call the car mechanic right away. Nevertheless, if you and your car are in a public place, you should push it to a safe area instead of starting the engine. You do not want to waste money to change the whole engine and regret later. After that, drivers should allow fuel removal professionals to drain and flush the wrong fuel out of the engine. And remember, car owners should only drive the car when all the steps are done.

What to Do When Starting the Petrol Engine with Diesel

Ok, the situation has become worse: You put diesel in gas engine and drove. In time like this, you do not need to know what happens if you put diesel in a gas car. In the case where you started the vehicle, you might want to drain the contaminated fuel totally out of the engine first before performing anything else. We need professionals to do this.

After that, car owners must use clean petrol with the purpose of flushing the fuel lines thoroughly. With the first two tasks completed, you have protected the engine of your automobile from further issues or damage. It is now safe to fill the car with petrol and there should be no more reason for worrying. Drivers can get inside the vehicle and drive it normally.

What to Do When Driving An Unleaded Petrol Car with Diesel

Now we talk about the worst situation. If you are already driving the vehicle that is running on diesel instead of petrol, what should you do? Everything apart from panic, that’s our first advice. By the time you realize that your automobile is having a fuel issue, stop driving and park at a safe spot. Next, car owners should call the fuel drain experts in order to flush the fuel tank and the fuel lines carefully. Remember, they must always perform a full flush since it is necessary for removing the contaminated fuel. Once the flushing progress is finished, the car is now free of contamination and should be ready to drive.

On the other hand, it does not hurt to be cautious about this. Even though this is just a small chance, your automobile might develop emission issues as a result of contaminated controls and sensors. If you are worried, let the technician give your vehicle a thorough examination.

The Effect of Diesel in Gas Engine

We now acknowledge what to do when putting the wrong type of fuel, so what happens if you put diesel in a gas car?

Being a driver, you might face some unexpected problems like pouring diesel in gasoline engine. You may or may not be aware of the fact that there is diesel in your gas car. So, how to figure out your fuel tank has diesel and what damages can it cause to the engine and other parts. Don’t worry! You will find it out right here.

Probable Damage

Regardless of the fact that both diesel and gasoline are refined versions of crude oil but, the procedure included to refine the diesel is quite different than the gasoline. This is why both components require different engines and the car as well, and we need to avoid putting diesel in gas engine.

Diesel in gas engine can be dangerous
Diesel in gas engines causes accidents. Cre:  Rich Pedroncelli | AP

However, diesel is heavier and oilier than gasoline so, when you pour the gas engine with diesel, the injectors feed the engine with loads of diesel as it sinks inside the engine. After this, when you will try to ignite the engine, the spark plugs won’t work and the engine, as a result, would be unable to get started. Moreover, forcing the engine to ignite might result in the burning of some parts and even the worst like fire catching. In addition, severe timing and cylinder issues might also occur.

So, never try to know what happens if you put diesel in a gas car. They both serve the different functioning of the engine and have different properties. If you want to know more about them, as well as what happens if you put diesel in a gas car, continue reading.


Before getting to know what happens if you put diesel in a gas car, it is crucial to spot signs of diesel in Petrol, and misfiring is one of the most significant symptoms. Misfiring in the engine is the most basic and common indication of a presence of diesel in the petrol. The engine will be unable to start and can cut or completely or might have smoky exhaust while driving.

So, whenever you discover your engine with these signs STOP DRIVING, immediately! Besides, switching off the engine as soon as you notice the signals can prevent many disasters with the diesel residue.

In other words, the signals that show the presence of diesel in petrol care are:

  • Engine misfiring
  • Engine cuts out
  • Smoky exhaust while driving
  • Non-responding engine


Putting Diesel in a Petrol Car vs Putting Petrol in a Diesel Car

Now we know the signs of Diesel in Petrol, it is time to understand what happens if you put diesel in a gas car. Another thing to acknowledge is that people often make the mistake of pouring the diesel engine with petrol and petrol engine with diesel. But, which one is more dangerous for the engine? Let’s find out here!

1. Which One is more Complicated?

It’s comparatively easy to fill petrol in a diesel car because the filter neck allows different sized nozzles that are smaller than the diesel nozzle to fill the oil inside. Therefore, one can easily mistake the petrol, which has the smaller nozzle, inside the diesel car. However, due to the smaller size, it’s basically difficult to fill the diesel through a big nozzle.

Diesel in gas engine causes accidents
Problems of putting Diesel in the gas engine. Credit: Tom Merton / Getty Images


2. Which Engine can Bear More?

Diesel engines are normally stronger than the petrol engine but, when the petrol gets in contact with the diesel engine, it acts as a thinner, which automatically dries out the engine. This results in the fuel and the engine to wear down through friction. After facing this situation your engine might never work or the damaged parts need to be changed. The chances for big problems are high. Therefore, taking the maintenance tips from the experts is essential.

In this situation, where the diesel engine has no lubrication in it, trying to start the engine can make some additional damages due to pre-explosion. Diesel requires high combustion to ignite, as the petrol is more volatile, the too much pressure inside the engine makes the petrol to combust prematurely. This, as a result, forces the pistons to go out of their natural order. This type of condition might be hazardous as many components inside the engine are blocked.

All the above guidelines regarding the damage of pouring the diesel in a gas engine, signs of diesel in petrol, and of course, the worst results of filling petrol in the diesel engine, will help you find the best car for you with a compatible engine.

So, whenever you discover the diesel in a gas engine or need to figure out the best car engine for you, follow this guide without having a double thought! After all, you know what happens if you put diesel in a gas car.

  1. guillermo cabala says

    my customer put diesel in a gas car and took the road to a nearby town. the car started to fail and he forced it. it caught on fire. can you explain?

    1. Anonymous says

      Perhaps the gas prematurely ignited in engine…

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