It might save you money, but it could also damage your engine and create more summer smog. Here’s what to know about how E15 will affect your car.
Starting on May 1, E15 gasoline will be more widely available, thanks to a waiver issued by the United States Environmental Protection Agency (EPA), which will temporarily halt seasonal restrictions on the use of the higher-ethanol containing fuel.
The move is aimed at lowering gasoline prices, which have escalated since the U.S. began its attacks on Iran earlier this year. But the waiver also comes with some downsides. E15 can damage some engines, plus worsen summer smog— both reasons why it’s currently banned in many places during warmer months.
“Also, E15 can degrade faster than E10, due to the higher ethanol content,” says automotive expert Steve Haney. “It may not be a good idea to fill up with E15 if you do not drive frequently, or if you are going to put your vehicle into storage.”
Here’s what to know about E15 gas, and how it will affect your car, motorcycle, lawn-care equipment and off-road vehicles.
What Is E15 Gas?
E15 is a blend of gasoline that contains 15% ethanol and 85% gasoline. It’s most commonly marketed as Unleaded 88, Regular 88, Clean 88, eBlend and Unleaded 15. While many gas stations sell E15, it’s typically restricted in the summer.
Ethanol is most commonly made from fermenting corn grain. When added to gasoline, it decreases oil consumption and oxygenates fuel, which in some cases can reduce air pollution. According to the US Department of Energy, more than 98% of US gasoline contains ethanol.
How E15 Differs from Regular E10 Gasoline
Standard gasoline in the US is E10, which contains 10% ethanol, whereas E15 contains 15% ethanol.
Why the EPA Is Allowing E15 Gas?
According to the EPA, the waiver is aimed at “fortifying the domestic gasoline supply chain and providing Americans relief at the pumps ahead of the summer driving season.” The waiver starts on May 1 and ends on May 20, though those dates may be extended.
Is E15 Gas Safe for Your Car?
It depends on your vehicle. The majority of cars made after 2000 can handle E15 gasoline, but check your owner’s manual to be sure. Older cars that are designated as “flex-fuel” can also run safely on E85.
Cars and Engines That Should Avoid E15
E15 shouldn’t be used in most pre-2001 vehicles, as it can damage gaskets and create fuel leaks and other mechanical problems. You should also avoid using it with small engines, such as motorcycles, ATVs, snowmobiles, boats and lawn-care equipment.
Does E15 Affect Fuel Economy?
Yes, it decreases gas mileage by a little less than 2%. “Doing the math here, if the average fuel economy for a modern vehicle is 27 miles per gallon, with E15 gasoline, you can expect to get about 26.5 MPG instead,” says Haney.
Does E15 Damage Your Engine?
It can, if your vehicle was made before 2001. E15 is also damaging to small engines, such as those in motorcycles, ATVs, boats, generators, leaf blowers, chainsaws and lawn mowers — especially if they go several weeks at a time without being used. “This will cause a small engine to run and perform poorly, possibly damaging it beyond repair,” says Haney.
One reason E15 can cause damage is because it’s hygroscopic, meaning it absorbs water, which causes fuel to separate. Ultimately, that can damage the plastic and rubber parts, like fuel lines, hoses and O-rings, plus corrode and clog carburetors and other parts of the fuel system.
“Ethanol is also hard on aluminum, which many small engines are made out of,” says Haney. “Manufacturers state very clearly in their manuals that using fuels with more than 10% ethanol will void the product’s warranty, so make sure to double check before filling up!”
How Much Money Will E15 Save at the Pump?
It depends on where you live, but in a recent interview, the president of the American Farm Bureau Federation and the Iowa Farm Bureau stated consumers can expect to save around 10 to 30 cents per gallon.
However, other experts aren’t convinced. As University of Minnesota professor Jason Hill recently told PBS, savings at the pump could be negated by higher grocery prices. For example, corn crops reappropriated from animal feed to ethanol production are likely to increase the cost of beef.
There are also indirect costs, such as higher ozone levels during the summer, which can cause heart attacks, respiratory issues and other health problems.
How To Tell If a Gas Pump Is Dispensing E15
Pumps dispensing E15 gasoline are federally required to have a yellow label disclosing its use. Also look for E15’s more common names: Unleaded 88, Regular 88, Clean 88, eBlend and Unleaded 15. E85Prices.com also shows which gas stations offer E15.
What To Do If You Accidentally Put E15 in an Incompatible Car
If you accidentally put E15 gasoline into an older, or otherwise incompatible car, it’s still okay to drive. But once your tank is halfway empty, fill it back up with standard E10 gas. “If you put E15 into a small engine like a motorcycle, you should play it on the safe side and drain the tank, then refill with E10 gasoline,” says Haney.
About the Experts
Steve Haney is a corporate technical trainer at Bosch Mobility Aftermarket, and has more than 35 years of hands-on automotive repair experience.
Sources:
EPA, “EPA Fortifies Domestic Fuel Supply” 2026
U.S. Department of Energy, “Ethanol Fuel Basics” 2026
PBS, “EPA approves sale of a higher-ethanol fuel to try to lower gas prices” 2026
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