What Happens When You Put Diesel In A Gas Engine?

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Have you ever wondered what would happen if you put diesel in a gas engine? Even though we are not mechanics, we can confidently say that after adding diesel to your gas tank, you’ll probably be speaking to one shortly.

We want to help you not only avoid mistakes but also know what to do if you accidentally fill up with diesel rather than gasoline. In that case, let’s get going!

Gasoline VS. Diesel

Heavy-duty trucks, semis, buses, boats, and other vehicles that may need a higher torque rating and more low-end pulling power are the ones that use diesel the most frequently. Light-duty trucks, SUVs, and passenger cars are the vehicles most frequently found with gasoline powertrains.

Diesel and gasoline have different physical characteristics even though they both come from crude oil. The consistency and aroma of gasoline are very different. Diesel fuel has a more viscous state of fluidity that resembles that of lightweight oil. When diesel tries to pass through the fuel system and engine parts of an automobile that runs on gasoline, these physical differences become relevant.

Additionally, diesel burns less readily than gasoline. Diesel and gasoline engines behave differently since each fuel has a unique autoignition temperature. Although a component known as a glow plug might be helpful when the engine is cold, a diesel engine uses the pressure created by compression within the engine to ignite the fuel. A gasoline engine uses spark plugs to do this. In other words, while gasoline ignites with fire, diesel heats up through compression. Furthermore, ethanol, a highly flammable organic compound used as a biofuel additive, is frequently added to gasoline in amounts up to 10%. Gasoline becomes even more combustible when ethanol is added.

In essence, diesel and gasoline engines are made to run on only one type of fuel, not the other.

Why Diesel Fuel Is Not The Same As Gasoline?

The density of gasoline and diesel is the main distinction. Compared to gasoline, diesel fuel has a higher viscosity or thickness. Diesel smells more like potent kerosene while gasoline is thin and has a paint thinner-like aroma. You can determine what kind of fuel is inside the container by giving it a quick sniff or slosh. It all comes down to how the engine uses the fuel to operate, which is the main way diesel differs from gasoline.

Diesel is categorized as combustible, whereas gasoline is flammable. An ICE’s cylinder chamber receives fuel injection by means of a valve opening. The engine block is propelled by the spark plug-induced ignition of the fuel. Direct injection of diesel fuel into the cylinder chamber prevents ignition and instead causes compression of the fuel. The outcome is the same. The engine operates as expected after being pushed downward by the cylinder.

The fuel used by the two different types of engines cannot be used together. In other words, you cannot run a diesel engine on gasoline or a gasoline engine on diesel. Diesel is too thick for a gasoline engine’s fuel pump system, and gasoline produces an explosion that is too big for a diesel engine to handle.

Does Diesel Fit In A Gas Engine?

Using diesel in a gas engine is never a good idea. The fuel in your fuel system’s octane level changes when diesel is used in a gas engine. This could harm your car in a number of ways and make a lot of smoke come out of your exhaust.

The likelihood is that your car will shut down if you keep driving. After that, you’ll need to call a tow truck to have it taken to a nearby mechanic. 


What Occurs When Diesel Is Put Into A Gas Engine?

Several things are likely to happen when diesel fuel enters the fuel system of your gas engine. So let’s take a closer look at what occurs and what problems may arise if this occurs to you.

Fuel Pump Issues

Fuel pumps made for gasoline cannot handle diesel because it is too thick. As the mixture becomes more viscous, the fuel pump will have a difficult time pumping the fuel through the engine of your car. If your fueling pump has any pre-existing conditions or is close to failing completely, this will put a great deal of strain on it.

Clogged Fuel Injectors

Any diesel fuel that gets past the fuel filter will clog the fuel injectors in your cars. This will eventually cause your car to shut off and become unusable.

As the gasoline in your car’s fuel system is burned up, you might be able to continue driving for a short while. However, it’s only a matter of time before the diesel clogs the injectors, forcing you to call a tow truck.

Clogged Fuel Filter

Diesel is thicker than gasoline, so it won’t be able to pass through your fuel system’s fuel filter as quickly. The oily diesel fuel is likely to clog your fuel filter right away and make your engine work harder.

How To Handle Putting Diesel In A Gas Engine?

Don’t freak out; putting diesel fuel in a gasoline engine is much safer than pumping gasoline into a diesel engine, which can be much more hazardous.

Imagine you unintentionally put 50% diesel in your gas tank. There’s a good chance your car won’t start, and you’ll need to have it towed to a garage so the tank can be drained.

What you should do is as follows:

  • How much diesel, roughly, was pumped into the gas tank? Knowing whether you only pumped in a drop or whether the tank is now half full of diesel fuel is useful. 
  • Don’t try to drive the car. Reduce the likelihood of expensive repairs by not operating the car. You can prevent diesel from getting sucked into the fuel line by not operating the car. Your engine could seize if you try to drive the car with diesel in it, which would likely necessitate costly repairs. Additionally, this needs to be addressed right away. Too much time spent letting diesel fuel sit can result in further harm. 
  • Call a garage. Inform the local garage you trust about the circumstance. They’ll probably advise emptying your gas tank. Make plans with the garage in advance so that the tow truck can deliver the car right to the garage when it shows up.  
  • Call a tow truck. Contact a tow truck company right away to have your car towed to the garage after you hang up with the garage.

What Does It Cost To Clean Diesel Out Of A Car?

You’ll need to remove the diesel from your car if you put it in a gas engine. The price of the repair can go up to $2500, though it may vary depending on the shop. Draining the fuel from your car’s tank can cost between $200 and $500, and if the fuel also gets into the fuel lines or engine, the costs quickly rise to around $1,500 to $2,500.

A sizable repair bill is involved here. To see if you can file an insurance claim for the repairs, you should call your insurance provider.

The majority of insurance policies do not cover expenses resulting from misfuelling. But when it comes to the coverages and any restrictions in your policy, only your insurance company can speak.


You now understand the consequences of putting diesel in a gas engine and are aware that even a small error could have a sizable negative impact on your finances. We advise you to double-check the fuel pump there. If you do, you can spare yourself the stress and financial costs.

Have you ever filled your tank with the incorrect fuel?

Read more about: What Happens If You Put Sugar In A Gas Tank?

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