Does Gasoline Evaporate? How To Prevent It and Save Fuel

The question “Does gasoline evaporate?” is a common one among car owners. The answer is yes; gasoline does evaporate due to its weak intermolecular properties.

Does Gasoline Evaporate

Apart from this primary reason, certain other factors are responsible for its evaporation. In this article, we’ll discuss the rate of gasoline evaporation and how to prevent this from happening.

Does Gasoline Evaporate When Exposed?

Yes, gasoline evaporates when exposed. It does this very quickly, often within 3 to 24 hours. However, it could evaporate faster depending on how much of it is exposed. A small amount of spilled gas can evaporate within 60 minutes to three hours.

Aside from these, other factors may affect the evaporation rate, such as where it is being handled. If you’re using gasoline outdoors, there’s a higher chance of evaporation because the wind quickly disperses hydrocarbon liquids in the gas.

Temperature and humidity also play a massive role in how fast gasoline will evaporate. Since these hydrocarbon liquids are pretty volatile, it’s relatively easy for your gas to evaporate quickly. You can expect your gasoline to evaporate within a couple of hours if left exposed. However, you should still be careful because, although evaporated, it is not too rare to see gasoline catch fire.

– Gasoline Evaporating Faster When Tank Is Empty

Gasoline will not evaporate faster even when your gas tank is empty. It will only evaporate faster from your fuel tank if there’s an unusual amount of air in your fuel tank. Contrary to what many might think, gasoline often retains its liquid form when poured into a fuel tank, and it remains that way if the car engine is turned off.

Once you turn on your car engine and there’s an increase in temperature, the gasoline will transform into vapor. Even in vapor form, gasoline will only evaporate if your fuel cap is broken or sealed loosely, letting in air.

Also, most modern cars are now fitted with EVAP (Evaporative Emission Control) systems, ensuring that vehicles’ gasoline vapors are safely stored before being disposed of to prevent environmental pollution. Hence, your gas won’t evaporate faster in an empty fuel tank as long as there’s a proper balance of air and temperature.

What Are the Factors That Affect the Gasoline Evaporation Rate?

The most common factors that affect the gasoline evaporation rate are temperature, humidity, and wind. If gasoline is exposed to extreme cases of each, then the rate of evaporation will most likely be accelerated. Make sure to keep gasoline in a sealed container to avoid evaporation.

Factors That Affect the Gasoline Evaporation Rate

– Temperature

Gasoline dissipates at 140 degrees Fahrenheit, which means the higher the temperature, the faster it will vaporize. Hence, leaving your gasoline exposed to hot weather can cause it to evaporate quickly. On the other hand, storing your gasoline in cold weather like winter is ideal as it is less likely to dissipate rapidly.

– Humidity

It is difficult for gasoline to vaporize and evaporate if exposed to a humid atmosphere. This results from large concentrations of water vapors in the atmosphere due to a drop in temperature. Gasoline won’t quickly evaporate as its fuel vapors will mix with the water vapors present, inhibiting the evaporation rate. In this case, spilled gasoline may not disappear because it competes with the water vapors in the atmosphere.

The chances of evaporation occurring become accelerated if gasoline is exposed in a less humid area. Since the air is relatively drier, gasoline dissipates faster than when released in a moist space.

– Wind

The wind is another common factor that strongly affects the rate of gasoline evaporation. If there’s a high amount of wind in the atmosphere, it’ll quickly disperse the hydrocarbon molecules in the gasoline into the air, accelerating evaporation. On the other hand, a gentle breeze will not cause gasoline to evaporate more quickly than expected.

How Do You Prevent Gasoline from Evaporating?

To prevent gasoline from evaporating, you can start by storing it in an airtight container, using a fuel stabilizer, and having a tight fuel cap. Once you’re able to do these and take other preventive measures, you can be sure to save money on gas.

How Do You Prevent Gasoline from Evaporating

– Top Up Your Tank

Although gas doesn’t dissipate in an empty fuel tank, you must always top up your fuel tank. A certain amount of air will always be present in your tank; however, a fuller fuel tank reduces the risk of unnecessary air getting into the tank and accelerating fuel evaporation. That way, you’re guaranteed more fuel efficiency, eliminating more stops at the gas station.

– Store Your Car in a Cool, Dry Place

As discussed earlier, gasoline is less likely to evaporate in humid conditions than when stored in a hot place. If you often keep gallons of gasoline at home, ensure it is stored in an airtight, cool, dry area.

Doing this will reduce the chances of air or heat coming in contact with the gas and causing faster vaporization. Hence, your gasoline is preserved for longer, reducing gas purchase costs.

– Park Your Vehicle Under a Shade

Parking your vehicle under a shade is another great way to prevent gasoline evaporation. Fuel is transformed to vapor when the engine produces heat; therefore, parking under a shade reduces the risk of dissipation.

Park Your Vehicle Under a Shade

If the car’s temperature isn’t high, several of the gasoline molecules may return to their liquid form during condensation. On the other hand, parking your car directly under sunlight will increase the chances of gasoline dissipation due to the high temperature.

– Add a Fuel Stabilizer

A fuel stabilizer is a must-have if you’re looking to prevent accelerated gasoline evaporation. It is usually made of similar chemicals as fuel and acts as a protective barrier for gasoline in the fuel tank.

A fuel stabilizer usually absorbs the hydrocarbon liquids of gasoline and inhibits vaporization. However, you must add the fuel stabilizer to the fuel tank before adding fuel so that both mix properly for more efficiency.

– Inspect Your Fuel Cap

Carry out routine inspections on your fuel cap to ensure it isn’t broken or sealed loosely. If your fuel cap is broken or loose, it could spill gasoline and introduce excess air to your fuel tank, increasing evaporation.

Hence, you should ensure your fuel cap is in excellent working condition to prevent loss of fuel via evaporation.

– Repair Seal Leaks

A gas cap seal, also known as a fuel filler cap, is an essential part of your fuel tank. It prevents air, debris, and other contaminants from reaching the fuel tank. If you discover that your gas cap seal leaks, you should immediately repair it. Fixing it will eliminate the issue of gas evaporation and save you more cash on gasoline purchases.

Repair Seal Leaks of Car

– Other Methods

You can save money on gasoline by keeping your fuel tank sealed tightly with no leaks. Keeping your tires inflated is another underrated way of saving money on gas. The more air in your tires, the less gasoline they consume to function correctly. Also, ensure that your fuel tank is always full and that your car runs smoothly with transmission oil.

Another way you can save money on gasoline is by driving more slowly. You consume more fuel when you speed than when you accelerate gently. Pay attention to your coolant, especially on hot summer days. Once you notice a drop, top up your coolant levels, and you’d discover an increase in fuel economy.


Now that you know gas evaporates quickly, you can be more careful when handling it.

Here’s a recap of the key points discussed in this article:

  • Does gasoline evaporate? Yes, it does. Gasoline can evaporate between 60 minutes to 24 hours, depending on how much is exposed.
  • Your gasoline is less likely to dissipate in an empty fuel tank as long as there are no leaks.
  • Temperature, humidity, and wind are all common factors that affect the rate of gasoline evaporation.
  • Filling your fuel tank, parking under a shade, and fixing seal leaks are great preventive measures against gasoline evaporation.
  • Driving slowly, using coolant, and inflating your tires can save gasoline money.

You can now prevent gas from evaporating faster and significantly save more cash on gasoline purchases when gas prices rise.

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