The Environmental Protection Agency has managed to get their recommendation to increase ethanol content in gasoline from 10% to 15%. On the surface, this can be viewed as a victory for the environmentally conscious consumers. However, this victory also spells disaster for nearly every auto warranty claim out there. We at CARCHEX are not opposed to being environmentally conscious, but there are several problems with this particular measure.

Why Ethanol Gas Voids Car Warranties

Ethanol gas, simply put, can put your vehicle under excessive wear and tear. This is especially true if you have a car older than the 2000 year. The fuel filters, piston rings and valves were not made with consideration of ethanol being in the system in older cars. Ethanol is highly corrosive to these parts, and can damage them in a fairly short amount of time. Also, ethanol has a shelf life of only two weeks, so unless you drive enough to keep burning it off, you can face even more problems.

Unfortunately, it is not as easy as choosing not to use ethanol at the gas pump. According to, there are only slightly over 4000 gas stations in the U.S. who offer pure gasoline, and many of these are concentrated in oil producing states and rural areas. It’s not that the prevalence of E10 gas stations is mandatory—according to the EPA, the endorsement of E10 fuel was merely a suggestion.

Vehicle Warranties and the E15 Endorsement

Eventually, auto manufacturers were able to produce engine components that could cope with the E10 fuel. Now they are up in arms about the endorsement of 15% ethanol fuel. The concern is that the E15 endorsement by the EPA will make it as prevalent as the E10 fuel is. Of course, most people will want to take the “environmentally friendly” alternatives, and that ultimately means there will be a spike in engine breakdowns. Incidentally, ethanol decreases gas mileage in the short term, which contradicts the idea that it is more eco-friendly.

One thing is certain—vehicle warranties, even if the claims are honored, will not be able to adequately address the problems of E15 fuel. Leaving the question of car warranty qualifications alone for a second, the manufacturers simply have not been producing components that are capable of handling the increased abuse that E15 fuel will put your engine through. Until such a time as they manufacture these components, engine problems from this fuel will increase, and unfortunately, it cannot be covered by most warranties.

Take it from us, even if E15 helps save the environment, it definitely spells trouble for your cars and your auto warranties. Avoid it as much as you can to protect your warranty.