Home Fuel System How Long Does Gas Last – Can You Keep Them For Long?

How Long Does Gas Last – Can You Keep Them For Long?

by Kelvin Yates

Your engine needs fresh fuel in the tank to work at its best. Gasoline works best within a specified time frame, whether it is giving optimal spark or excellent fuel mileage. Fresh gas also ensures that your high-tech engine operates at its best, as today’s high-tech engines frequently require premium gasoline.

However, if you don’t drive very often, the gasoline in your tank can linger for days, weeks, or even months. Furthermore, because fuel degrades over time, it’s vital to take steps to maintain it fresh. This is so that your vehicle performs at its best.

Does gasoline go bad?  When should a gasoline stabilizer be used? Let’s have a look at the topic of gasoline shelf life and some procedures you can take to ensure that the fuel in your tank lasts as long as possible.

Does Gasoline Go Bad

So, how long does gas last? What is the maximum amount of time gasoline can be left in a car? Depending on the type of gas and how it is stored, gasoline can last anywhere from three months to three years. And if you need to learn more, check out our detailed look at what color is gasoline.

All fuels will naturally degrade over time as a result of exposure to oxygen (also known as oxidation). However, not all fuels are created equal. The average gallon of gasoline sold at a gas station will last three months, but some types of gas will last longer.

Find out more about the shelf life of three popular types of gasoline in the following sections.

Up To 6 Months With Pure Gasoline

Even if gasoline is easily accessible at the local pump, there is always the possibility of a scarcity of this valuable resource. As a result, gas storage may become necessary to last for extended periods of time or when prices are low and you want to stockpile. Your investment will be protected if you know how to properly store gasoline.

Pure gasoline is petroleum-based and contains no ethanol. As such, it last up to six months before rapidly degrading due to oxidation. Pure gasoline is easy to avoid becoming polluted with moisture because it does not absorb water like other forms of gas. There are various factors to consider when deciding how long fuel will last.

These are some of them:

The gasoline you buy at the pump will last 3 to 6 months. But, only if kept in a well-sealed container and kept out of direct sunlight. After this time period, the gas quality will have deteriorated to the point where it will no longer be suitable for use in most vehicles due to its low combustibility.

After three months of storage, the fuel in lawnmowers and associated products like weed whackers may not be sufficiently flammable. The shorter shelf life is related to the inefficiency of the ignition mechanism, which in garden equipment is often of lesser quality than in a car.

Factors Affecting The Longevity

This 3-6 month longevity time frame can be affected by two key factors:

How Long Does Gas Last

1. The Use Of A Fuel Stabilizer

A fuel stabilizer can keep gasoline usable for 1-3 years if used properly. They’re formed of petroleum products and work by preventing the gasoline from oxidizing and breaking down chemically. It’s mostly made up of antioxidants and lubricants.

The stabilizer makes a bond with the gasoline, repelling water, preventing evaporation, and preventing sticky fuel. Old, viscous fuel may wreak havoc on engines by forming a deposit that can soon destroy a carburetor. As a result, it’s recommended to avoid it.

You only need a couple of ounces of stabilizer for a full automobile tank. If you use too much, the fuel will become diluted, reducing the amount of power you can extract. Pour the stabilizer into a nearly empty tank or container, then fill it with gas for best results.

This ensures that the stabilizer is uniformly distributed throughout the gasoline. If you’re using stored fuel in a motorized machine, let it run for 5-10 minutes to get the stabilized fuel into the engine for optimal protection.

2. Ethanol Concentration

Because of the necessity to find an alternative, sustainable fuel source, ethanol has become a popular additive to most gasoline sold. Unfortunately, because it oxidizes so quickly, ethanol has a negative impact on the longevity of gas.

Ethanol is also hydrophilic, attracting water molecules. When water is caught in gasoline, it separates into discrete layers of ethanol and gasoline. This makes the blend difficult to burn. In general, the higher the ethanol content, the shorter the longevity. E10, a blend of 90% gasoline and 10% ethanol, has a three-month shelf life.

Evaporation and oxidation will impact pure gasoline as well, although at a slower rate. Hydrophilic means it repels water, and pure gas is one of them. Pure gasoline will last at least 6 months if kept properly because of these qualities.

Your gas tank will only last about a month if you keep it full with gasoline. This is owing to the fact that your gas tank is not sealed. As a result, gasoline is exposed to a lot of oxygen, which can cause it to oxidize and deteriorate. Keep vehicles like boats, mowers, and generators that are going into storage with nearly-empty tanks in mind. You won’t have to remove old gasoline before utilizing it this way.

Up To 3 Months For Ethanol Blended Gas

“Regular gas” refers to ethanol-based gasoline, which is typically 90% petroleum and 10% ethanol and is marketed at gas stations across the country. This type of gas has a shorter shelf life than pure gasoline, lasting on average only three months. Unlike pure gasoline, ethanol-based gas readily absorbs moisture, potentially contaminating the fuel.

Unfortunately, it’s very impossible to tell how old the gas is when you fill up your car at a gas station. This is because the gas may have already been a few days or weeks old by the time it reaches the gas station and you fill up your vehicle.

The fuel may have been sitting in the gas station for almost a month by the time you pump it. So, if you’re wondering how long gas can sit in a car, the answer is probably up to three months from the time you filled up at the gas station.

Up To 3 Years Shelf Stable Gas

Shelf-stable gasoline is the type of gasoline with the longest shelf life. Fuel stabilizers are petroleum-based additives that can be applied to gasoline before keeping it in your garage and can be purchased online or at local hardware stores. Fuel stabilizers reduce the rate at which gas oxidizes, allowing it to last longer.

How Long Does Gas Last

Determine The Difference Between Polluted And Old Gas

Pouring a little amount of your stored gas and freshly pumped gas of the same type into two transparent glass vessels and comparing them side by side is the easiest approach to examining the condition of gas. If the gasoline is only slightly darker than new gas or smells sour, it is simply old and has most likely lost its effectiveness, but it is not polluted.

If an ethanol-blended gas has various layers of gas and ethanol, i.e., if the fuel has separated or if the gas is noticeably discolored (the color of milk chocolate or rust) or comprises grit or slime, it has been contaminated by dampness or solid oxidation by-products, respectively.

Polluted gas should never be used to power machinery or vehicles because it can cause corrosion or leave sludge or varnish deposits (a thin, translucent brown or orange film) on fuel system components, which can cause irreversible harm.

Because, despite its weak combustibility, both the gas and the vapors it generates are still combustible. They could cause a fire or explosion if the storage container becomes broken over time and the gas leaks into its surroundings, dispose of compromised gasoline as soon as possible.

How To Spot Bad Fuel

The chemical characteristics of gasoline vary as it ages. As a result, the engine is unable to effectively process the fuel. There are few signs to look for when you find bad gas in a car.

The most fundamental is the “check engine” light. If the automobile is functioning normally and the engine has oil, this light could be caused by incorrectly burned gasoline. Take your vehicle to a competent technician or dealership for an inspection.

If the car has operating issues, this is another sign that there is bad gas in the car. This could indicate a failure to start, a sluggish ignition, a rough idle, or a lack of power when driving, particularly when accelerating.

The appearance and odor of gasoline can also be used to detect its condition. Poor quality fuel will appear darker or muddier. It will also have a sour or unpleasant odor that is not characteristic of regular gasoline. Some people could even say the gasoline smells rotten.

In all of these cases, the defective fuel must be removed from the tank. The vehicle will not run properly, but poor gasoline can also harm internal engine components and leave a sticky residue that can cause fuel line blockages. Bad gasoline, particularly ethanol-based gas, can suck in water vapor, which can damage the tank and fuel system. The damage can be expensive to fix if left unattended for a long time.

The Three Major Causes Of Gas Degradation

Gasoline will change over time and will no longer work as well as you had hoped. The main reasons for this are oxidation, water, and evaporation, which are all major environmental concerns.

1. Oxidation

One of the primary elements in combustion is oxygen, but it also causes oxidation. As weeks and months pass, oxygen molecules in your gasoline begin to tap healthy hydrocarbons and change their structure. Thus, resulting in increased oxidation. As a result, combustion isn’t quite as fantastic as you may expect.

2. Water

When you put ice cubes in a glass of soda and don’t drink it, what happens? Your drink has been diluted. Similarly, you don’t want any extra water in your gasoline, but there’s one compound that doesn’t like to follow the rules: ethanol.

In the United States, most gasoline contains a set amount of ethanol – usually 10%. (E10 for short). Unfortunately, ethanol is very attractive and attracts water molecules in the air surrounding it, shortening the shelf life of gasoline. The higher the ethanol content of your gas, the faster it will expire.

3. Evaporation

What’s more? Some hydrocarbons are heavier than others, whereas some evaporate more quickly.  In a nutshell, summer gasoline contains heavier hydrocarbons because hot temperatures evaporate lighter molecules, and winter gasoline contains lighter hydrocarbons to help your engine function smoothly in the cold. Increased evaporation equals increased oxidation.

What Happens If You Put Old Gasoline In Your Car?

All of this concern about bad gas in cars begs the question of what happens when you use old gas. Will your engine blow up if you put old gas in it? Most likely not. On the other side, old gas might cause the following issues:

How Long Does Gas Last

  • Corrosion in the fuel system owing to the separation of water and gas;
  • Residue and gunk build-up in the fuel system, which can lead to blockages;
  • Reduces efficiency and poor engine performance

It’s not the end of the world if you leave ethanol-blend gasoline in your car for two months. However, leaving old gas in your automobile is a sure-fire way to shorten your vehicle’s lifespan and pile up expensive repair fees.

Furthermore, storing old gas and then using it to power a generator or a vehicle can cause your engine to misfire or even fail to start. This is especially true if your gas has passed its expiration date. In so doing, it will become much less flammable as it ages.

What Is The Best Way To Store Gasoline?

Gasoline should be stored in a tightly sealed plastic container or a metal tank. The chosen vessel’s volume should not exceed a limit of 5 gallons. Labeling the containers is also required by law to comply with fire regulations.

It is critical to use a sealed container to prevent excessive air and moisture from getting into contact with the gasoline. Despite the fact that pure gas repels water, it will mix with the fuel and reduce its combustibility. Maintaining gasoline in non-humid conditions is also critical for maximizing its shelf life.

Humidity, combined with high temperatures, can make gasoline highly flammable, in addition to increasing the water content. As a result, it’s preferable to maintain your stored gasoline in cool, dry places that aren’t exposed to direct sunlight.

It should also be a well-ventilated area without any electrical devices or open flames. It would be ideal if it were in a separate location from the house. The dangers of storing fuel can be reduced if these instructions are followed.

Make it a practice to stir the gasoline every now and then while it is being stored. When trying to get the most out of your gasoline stabilizer, this level of caution is extremely important. The stabilizer will circulate and protect the fuel more effectively if you mix it frequently.

Methods For Keeping Gasoline Fresh

You have various options for keeping your car’s gas in good condition. When you don’t drive as much as you used to and a tank of gas lasts longer than you expected, topping it off can keep it fresh. When the gas tank is full, there is less air inside, which reduces the risk of excessive condensation and fuel spoiling.

Another technique to care for a tank of gas is to drive it on a regular basis. Even, if it’s only for short distances. This not only keeps the fuel from degrading, but it also means you’ll have to fill up the tank more frequently.

Evaporation occurs when oxygen within a fuel tank causes gasoline to lose part of its chemical properties. To combat this, keep your tank full, which limits the amount of oxygen within. If you won’t be driving your car for a long time, adding a fuel stabilizer to the tank is a tried and true approach to extend the life of your gasoline.

It’s advisable to apply a fuel stabilizer to a full tank of fresh gas before driving. However, adding a fuel stabilizer to old gasoline will help to slow down the decomposition process.

A little container of gas stabilizers can be found at your local car parts store. Sta-Bil and SeaFoam are two well-known brands of fuel stabilizers.

If you must store gasoline, keep it in three-, four-, or five-gallon gas cans. And, with airtight covers in a cool environment with minimal humidity and oxygen.

What Is The Best Way To Get Rid Of Expired Gasoline?

Does gasoline go bad? When gasoline has been held past its expiration date and cannot be used to supplement new gas, it must be disposed of. Despite its lower combustibility rating, expired gasoline is still highly combustible and must be disposed of safely.

Even if you only have a tiny amount to dispose of, resist the urge to dump it down the sink, into the sewer, or near a body of water. Otherwise, it will contaminate the surrounding ecosystem and destroy plants, wildlife, and drinking water. Instead, contact city garbage or the local fire department for assistance.

Typically, you’ll be obliged to drive your expired fuel to a designated disposal location and pour it into a larger container there. To avoid placing yourself at risk, make sure you transport the fuel in an approved sealed vessel.

Facts about Gasoline and Car Maintenance During COVID-19:

  1. Due to COVID-19, many car owners are driving less, resulting in longer periods of time where their cars are not being driven.
  2. Gasoline has a shelf life that varies depending on the fuel type, with regular gasoline lasting three to six months, diesel lasting up to a year, and Ethanol losing combustibility in just one to three months.
  3. Fuel age is difficult to track as it begins in a refinery and may sit for an extended time at gas stations.
  4. Bad fuel can cause operational problems in a car such as failure to start, rough idle, loss of power, and trigger the “check engine” light.
  5. Bad fuel can cause damage to internal engine components and create blockages in the fuel line.
  6. Bad fuel can be identified by its appearance and smell, and it’s necessary to remove it from the tank to prevent damage.
  7. To prevent fuel from going bad, try driving your vehicle a few times a week or using a fuel stabilizer to combat fuel breakdown.
  8. Topping off your tank when you fill it can limit the amount of oxygen and moisture in the tank that can cause corrosion and water contamination.
  9. Excess gasoline should be stored in an airtight container within a cool, low-humidity, low-oxygen environment, and containers should be no more than three to five gallons in size.
  10. If you suspect bad fuel or have operational problems with your car, take it to a certified mechanic or dealership to investigate.


Here are some popular FAQs:

How Long Can You Store Gasoline

Regular gasoline has a three-to-six-month shelf-life; however, diesel can last up to a year before degrading. Organic-based Ethanol, on the other hand, is susceptible to oxidation and evaporation and can lose its combustibility in as little as three months.

What Color Is Gasoline

The color of gasoline is clear in its natural state. After the gasoline has been drained, all that remains is a clear, translucent liquid. In each type of gasoline, different dye colors are employed. It’s easy to tell them apart from this way. Each gasoline kind has a different hue. Regular gasoline is typically greenish or slightly bluish in appearance. Meanwhile, midgrade gasoline is yellowish in appearance. Then, there’s premium gasoline, which is usually pink in color and has a high octane rating.

How Many Miles Does A Full Tank Of Gas Last

The number of miles a tank of gas can propel a car is determined by the vehicle’s make and model, its mpg, and the tank’s capacity. A gas tank can contain 18 to 25 gallons of gas on average. In addition, the average MPG is 24. A full tank of gas will allow you to drive 200 to 400 miles.

How Long Does Gas Last In A Can

In a can, standard E10 gasoline offered on most forecourts in the United States will last around three months. The presence of ethanol in the fuel causes it to evaporate and oxidize more quickly than pure gasoline. Non-ethanol gasoline is a better long-term storage choice, with a shelf life of up to six months if properly maintained.

Does Gas Expire

To summarize, gasoline can deteriorate. However, there is no hard and fast rule about when it will expire. How gasoline is stored, ethanol levels, the time of year, and other factors all play a role in how long it remains good. Gas can be stored properly for 3 to 6 months; adding fuel stabilizers can increase the shelf life by a year or more (under optimal conditions, of course). However, the gas in your car’s tank will most certainly begin to degrade in about a month.

How Long Does It Take For Gas To Go Bad

The type of fuel utilized, as well as how and where it is stored, all play a role. Heat, oxygen, and humidity all affect the condition of stored fuel. Pure gas will degrade and lose combustibility in three to six months if stored in a sealed and labeled metal or plastic container owing to oxidation and evaporation. Two to three months is the shelf life of ethanol-gasoline blends. Fuel-stabilized gasoline has a shelf life of one to three years under optimal conditions. In just over a month, the gas stored in an automobile tank starts to degrade.

What To Do With Old Gas

Gasoline is a potentially hazardous substance that should never be dumped on the ground. Always properly dispose of or recycle it by taking it to the designated location. Most cities have at least one hazardous waste disposal center where you can dispose of old gas. All you have to do now is locate one. You can also contact your local fire department to find out where they recommend sending the old gas.

How Long Does Ethanol Free Gas Last

Regular gasoline’s restrictions are overcome by ethanol-free fuel. The extended lifespan of ethanol-free gas is one of its advantages over conventional gas. Ethanol-free gas can be stored for up to 6 months without losing its quality. Meanwhile, if you’re asking, how long does stabilized ethanol-free gas last? If you use the right stabilizer, it can last up to a year.

Final Verdict – How Long Does Gas Last

How long does gas last? Many drivers are always looking for methods to save money at the gas pump. They may opt for a vehicle that is the most fuel-efficient, such as a Honda Insight or Toyota Prius. This, however, is not an option for everyone, particularly for those who require larger vehicles for work.

Trucks and huge SUVs typically consume more gas than smaller automobiles. For some drivers, limiting daily driving as a way to save money makes sense. Allowing gas to linger in your car’s tank for an extended period of time is not a good idea. Now that you know what the average gasoline shelf life is and what you can do to extend it.

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