Published May 07, 2013
| Popular Mechanics
E15 fuel has been certified for sale in the United States and is slowly beginning to show up at filling stations. Here’s a quick rundown of what you need to know about this new fuel option.
What is E15 and why should I care?
E15 is shorthand for gasoline blended with 15 percent ethanol. The reason it's a big deal is that ethanol is fairly corrosive to rubber and certain metals, so it can cause damage to vital components. Ethanol also attracts and bonds with water from the air, and that water can separate out inside the tank due to phase separation. If your vehicle sits for long periods between use, the moisture settles to the bottom of the tank and can potentially clog in-tank pumps and filters. Damage is also possible in fuel lines, injectors, seals, gaskets, and valve seats as well as carburetors on older engines.
Is it really okay for my car?
This is a tricky question and the subject of a lot of hand-wringing right now. The gas you use now is often 10 percent ethanol, but some industry groups believe the higher concentration of E15 will cause problems. All cars 2007 and newer should be compatible with E15 because automakers have changed the formulation of the affected components. The EPA has certified vehicles in the U.S. fleet made in 2001 or newer, and all Flex Fuel–capable vehicles (able to use up to an 85 percent ethanol, 15 percent gasoline mix) as E15 compatible. One study conducted at Kettering University found no remarkable degradation in fuel systems all the way back to 1995 model years. But the main issue is whether or not your vehicle will be covered under warranty for any damage caused by E15 usage, and in many cases the answer is no. GM and Ford have certified their own vehicles starting with the 2012 and 2013 model years, respectively, so some brand-new cars will have no trouble at all.
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My car is older than 2001. What should I do?
Don't fill your fuel tank with E15, simple as that. Even though the new fuel is coming to market, the gasoline or E10 you fill your tank with now will still be available. There is a twist, though. At gas stations that use blender pumps (a single spout that dispenses all octanes) you'll have to purchase at least 4 gallons of E10 to insure any E15 in the hose is diluted to safe levels in your fuel tank. Fuel pumps will be required to have a 4-inch-square label warning motorists not to use the fuel for uncertified engines. With that in mind, the best advice if you have an older car is to stick to stations that have not switched over.
Will this damage my lawnmower, boat, jet ski, snowmobile, or four-wheeler?
It sure will if you don't pay attention. Generally, small engines are not designed to deal with the more corrosive E15 blend. And, as we mentioned in 2010, ethanol forms a brown goo when left in a fuel tank too long, which can clog fuel-system components. Two-stroke engines run hotter with an ethanol blend, which accelerates the potential damage. And ethanol can wreak havoc on fiberglass fuel tanks in older boats. Groups like the National Marine Manufacturers Association and Outdoor Power Equipment Institute have issued strong warnings to consumers to pay attention to their fuels or risk severe engine damage. Use a fuel stabilizer if the engine will sit for more than a few weeks without use; this will reduce the ethanol–water separation and potential gumming issues. Be careful to avoid using E15 in uncertified engines like these, at least until the subject is studied more thoroughly, and the engineering catches up to the fuel.