How Fast Does Gas Go Bad Just Sitting In Your Automotive?

In what would be the quintessential “first world problem,” consider that wealthy individuals with large automobile collections need to do constant maintenance to mitigate the consequences of expiring gasoline. Opportunities for the common person to fret about old gas are much farther and fewer between, and typically involve lawnmowers or portable generators. But when you might have a automobile that may sit for a 12 months (or years), you’d higher exercise due diligence to forestall that fuel from damaging engine components, leaving gummy residue that acts like plaque in arteries.

Usually, non-ethanol gas lasts anywhere from three to 6 months in your gas tank. As for ethanol blends like E10 (10% ethanol, 90% gas), you will be shocked to listen to that Minnesota Corn, whose mission is to “maintain and develop markets for corn and corn co-products,” says E10 will last no less than six months, and longer with good storage. Meanwhile, market research firm J.D. Power (you realize, the longtime award-giver and name most heard in Chevy ads for some time) says ethanol fuels can lose combustibility in only one to a few months. 

Also, while modern cars are designed around gasoline having a certain ethanol content in fuel, older cars with untreated rubber and plastic seals can apparently suffer serious damage. So, in the event you’re storing gas in your Ford Model A or Bugatti Royale, perhaps use straight gas with no additives. 

Should you desire to stockpile gasoline like a dragon keeps gold, keep in mind that irrespective of what you do, gas won’t last ceaselessly, but you may preserve its freshness for a surprisingly very long time. First, store it in airtight, fuel-rated plastic containers with as absolutely little air in them as possible. Then, put those containers in a cool, dry place. If you might have access to, say, the Subterranean Ultra Secure Supercar facility and its nitrogen-only atmosphere that requires robot employees, a lot the higher. Don’t expose your gas containers to extreme heat or cold, either. Gas likes a stable temperature; otherwise it’s going to evaporate and oxidize faster.

In the event you are one in all those wealthy individuals with an enormous automobile collection, you may take the cars out for a brief spin every few weeks. Then, top off the tank with fresh gas, which concurrently reduces oxygen levels within the tank to forestall evaporation and limits room for moisture buildup. I’m available day or night to come back drive the cars, a sacrifice I’m willing to make. I’ll make certain to vary the oil so it doesn’t go bad, either.

You can even add fuel stabilizers that can keep your gas from evaporating; then you might find a way to store fresh gas for as much as two years. In keeping with tests from FortNine, the highest performers are STA-BIL and K100. Still, even in the event you do use stabilizers and store your gas in a dehumidified cave, at all times check your gas before using it. You will know in case your gas has gone bad if it smells stale or sour, transitions from a beautiful amber color to a dark orange, or thickens like syrup, then it’s no good. No word on whether the flavour changes, though.

In keeping with Sunoco, plain 87 octane lasts three months before degrading, but 93 octane can last nine months before any appreciable degradation occurs. Higher octane rankings equal more-stable fuel. Race gas, because of its extreme refinement and octane-preserving chemicals, can last two years or more with careful storage. Uncareful storage kills it faster, because octane boosters like methylcyclopentadienyl manganese tricarbonyl (MMT) break down after mere minutes in sunlight.

Gasoline manufacturers must concurrently increase knock-preventing octane, keep fuel inexpensive, and tailor fuels to forestall vaporizing in various climates, and these goals are interwined. Relatively inexpensive additives can have low boiling points, comparable to butane, which boils at 32 degrees. Racing fuel has additives that boil at higher temperatures (80 degrees or more) but are pricier. 

To see how various fuels can stay stable in temperature extremes, manufacturers test fuel blends by sealing them in containers and heating them to 100 degrees. This produces a Reid vapor pressure (RVP) measured in kilos per square inch (psi), with higher pressures equaling higher volatility. This is the reason higher-RVP fuels, around 12 psi or more, are higher suited to cold weather while the alternative is true in warm weather. Federal law mandates an RVP pressure of 9 psi for fuel sold between June 1 and September 15, aka, “summer season,” to forestall gas evaporating and releasing ground-level ozone. Individual states will be even stricter, comparable to California, which limits RVP pressures to 7 psi. 

So, once you wonder aloud why gas prices are so high, it is not just fuel taxes and delivery costs, though they’re huge aspects (remember when a distant gas station within the Mojave desert wanted $8.59 a gallon?). Equipment used for RVP testing is dear, and the prices get passed to you.