Gasoline has been common in numerous vehicles and internal combustion engines.

Nevertheless, many forget that it also has an expiration date, just like any other fuel option. They keep using the gas even after it has gone bad, leading to dangerous accidents and inefficient operations that cost thousands of dollars to fix.

This guide will answer how long gasoline can be stored and provide extra tips to help you recognize the symptoms of bad gas. Keep scrolling.

How Long Does Gas Last in A Car?

Regular gasoline from standard gas stations usually lasts from 3 to 6 months. Still, several gasoline types might last much longer (e.g., 1 to 3 years for fuel-stabilized gas) or shorter (ethanol-blended gas can survive 2-3 months before succumbing to evaporation and oxidation).

The detailed breakdown for each type of gasoline is as follows:

Pure Gasoline: Pure gasoline is petroleum-based and includes no ethanol. Therefore, it does not absorb too much water like other gas types and faces much fewer risks of moisture contamination, easily lasting up to 6 months. Note that after 6 months, it will start degrading fast due to oxidation.

Regular/Ethanol-Based Gasoline: Most gasoline distributed at common gas stations is ethanol-based (mostly E10 with 90% petroleum and 10% ethanol). As a result, unlike pure gasoline, Ethanol-based fuel absorbs moisture and becomes contaminated quickly, shortening its shelf life to only half of pure gasoline (up to 3 months).

Unfortunately, it’s almost impossible to figure out the gas’s remaining life when filling your vehicle at the gas station. Gasoline usually takes some time, probably several days or weeks, to reach the station, then sits there for another undetermined period of time before getting pumped into your car.

Shelf-Stable Gasoline: Considered the most durable option out of the three, it can function well for up to 3 years. You can also purchase fuel stabilizers (online or from local stores) and other petroleum-based additives to slow the oxidation and make the gas last even longer.

Why Does Gasoline Go Bad?

Many factors contribute to gasoline conditions, but water contamination and chemical deterioration play the biggest roles.

Chemical Deterioration

Gasoline comprises several chemical compounds, some more volatile and lighter than others. Once contacted with air, particularly oxygen, they react and evaporate, resulting in the signature smell many of us have long associated with gasoline.

After these volatile compounds have evaporated, the gasoline is reduced to a thick, varnish-like substance that doesn’t burn well. As a result, you will find the fuel system components (e.g., fuel injectors or carburetors) getting clogged.

Water Condensation

Never let water enter your fuel system; it’s one of the worst things that could happen to your gas!

Sometimes, cold temperatures are enough to cause serious condensation on the inner surfaces of the fuel tank; harsh winters even block and freeze the fuel lines.

Water also leads to serious corrosion in fuel systems, as the rusty parts fail to hold themselves together and eventually fall apart. Once the rust clogs your gas lines, it will be impossible for the car engine to access sufficient fuel and run properly.

Symptoms of Gasoline Going Bad In Cars

Watch out for these telltale signs of bad gasoline:

Acceleration Difficulties: Engine hesitation and late response after you push the gas pedal usually mean the combustion chamber oil has been contaminated. In worse cases, the car will not even speed up at all.
Speed Fluctuation: Sudden speed changes (even though you do not even touch the brake pad or gas pedal) might result from bad gas.
Your Vehicle Stops Running: Does your engine suddenly shut down while driving? Chances are the car does not have enough power due to poor-quality gasoline.
The Engine Cannot Kick Off: Struggling to start your engine? The fuel might have been contaminated by water or other substances.
Broken Fuel Filter: A bad filter will compromise filtration, allowing sediments and debris to invade your gas tank and cause engine problems.
Sputtering: Audible noises (e.g., sputtering or pinging during driving or idling) indicate uneven combustion caused by bad gas.
Check Engine Light: For some car models, an illuminated CEL possibly signals your fuel is not clean enough to operate the engine properly.
Bad Fuel Efficiency: Bad gas forces the engine to work much harder, increasing fuel consumption.

Can You Still Use Bad Gasoline For Your Car?

Yes, if the gas is not too contaminated or mostly goes bad due to old age. You can mix it with new gas (1:3 ratio) and gently shake the fuel mixture to combine. If desired, add some fuel stabilizers to slow the oxidation and evaporation.

Note:

Diluted gas is not as good as fresh gasoline, so you might have to try to start the car several times.
If the gasoline is seriously degraded, rejuvenating it is not a good idea; consider discarding it. To dispose of gasoline properly, put it in a certified gas container and transport it to a disposal facility approved by your local authorities.

Tips to Extend The Gasoline Shelf Life

Use gasoline stabilizers or fuel treatment additives to slow the degradation.
Store the gas in an approved, well-sealed plastic container in a dry and cool place.
Keep the gas in optimal conditions; do not expose it to excessive moisture and air.
Rotate the stored gas regularly; long-term storage is not highly recommended.

Conclusion

Gasoline usually lasts from one month to a whole year, although you can apply numerous extra maintenance tips to extend the life of gasoline even longer. And while rejuvenating aged gas is possible, consider buying 100% fresh fuel to ensure your engine performance is always at its best.