Does Gasoline Go Bad?

We get this question all the time on our tech support lines and on Facebook.

For most of us, gasoline never seems to sit around for very long. But when you do store gas or go a long time without using it, the question arises: does gas go bad? Let’s take a closer look at the shelf life of gasoline and what can happen when you store it for too long.

Does Gasoline Expire?

The answer is yes. How long does gas last? That depends on a variety of factors, such as what type of fuel it is and how and where it is stored. Heat, oxygen and humidity all have an impact on the condition of stored fuel.

In general, pure gas begins to degrade and lose its combustibility as a result of oxidation and evaporation in three to six months, if stored in a sealed and labeled metal or plastic container. Ethanol-gasoline blends have a shorter shelf life of two to three months. Fuel stabilized gasoline can last between one and three years under optimal conditions. Gas stored in a car tank begins to degrade in just about a month.

The Dangers of Using Old Gas

Old gas does not become contaminated necessarily, but rather loses its combustible properties and volatile compounds. When you use gasoline that’s too old, it can damage internal engine components. It may also start to form a gum residue that could cause blockages. If there’s ethanol in the fuel, it may draw water vapor into your fuel line, which could result in internal corrosion.

How to Properly Store Gas to Make It Last

Gasoline should be kept in an airtight container. You should always label when the gas was purchased and stored. Keep gas in a cool, low-oxygen environment. If your stored gas becomes exposed to high heat and humidity, it can increase the volatility and potential for fire and explosion. For this reason, having a container with more than five gallons of fuel is not recommended.

When you have an automobile, machine or piece of equipment with a full tank that’s idle for a prolonged period, using a fuel stabilizer additive is the easiest, most efficient way to help keep its potency.

Identifying Old Gas

Labeling, properly storing and knowing how long it takes for gasoline to go bad is your first line of defense against using fuel that’s too old. When in question, check the color of the gas compared to fresh fuel. As gasoline ages, it tends to darken in color. The smell of gas can also be a dead giveaway that it’s past its prime. If you detect a sour scent or it smells spoiled, it’s an indicator that the gas has gone bad.

Learn More About Making Gas Last in Your Vehicle

Contact the experts at Rislone for additional insight into how long gas lasts, and use our store locator to find the store nearest you with our line of high-end, stress-tested lubricants, coolant treatments and fuel system cleaners.