Blogger David Woodsmall warns that E15 fuel (that is a blend of 15% ethanol and 85% gasoline) might be bad for some cars that are not certified to accept it:

One of the chief complaints by E15 opponents is that ethanol (an alcohol) is corrosive to many of the metals, plastics and rubber components used in internal-combustion engines and their fuel systems.


The auto industry and other E15 doubters cite corrosion as one reason more study is needed before the fuel is released. While modern engines have been designed with E10 blends in mind, their ability to use E15 for prolonged periods without damage hasn't been sufficiently tested, opponents argue.

Fox News reported that AAA warned cars older than 2012, because it is going to damage your car engine, and that ten car companies warned it would void your warranty against fuel-related claims.

Meanwhile, the EPA reports that E15 is safe for vehicles 2001 and newer.

Does E15 fuel damage cars newer than 2001 that are not certified for E15?


2 Answers 2


Does E15 fuel damage cars newer than 2001 that are not certified for E15?

The Data Says No.

While there's much debate on E15, the actual research into E15 on non-E15 cars appears to fall on the "no risk of damage" side. Much of the anti-E15 side appears to be speculation and anecdote and risk aversion with few actual controlled tests.

The Department Of Energy's "Review and Evaluation of Studies on the Use of E15 in Light-Duty Vehicles" states in its Overall Conclusions...

The project team reviewed 43 studies relevant to E15 usage in 2001 and newer model year on-highway automobiles. These included 33 unique research studies, as well as 10 related reviews, studies of methodology, or duplicate presentations of the same research data.

The data presented in [studies with relatively large numbers of vehicles] did not show any evidence of deterioration in engine durability or maintenance issues for E15 (or E20) in comparison to E0 and E10 (when tested).

Materials compatibility testing provides no evidence that 15 volume percent ethanol blends will cause increased rates of metal corrosion in comparison to 10 percent blends. In most cases increasing ethanol content from 10 to 15 volume percent had no significant effect on elastomer swell.

For 2001 and newer cars emission studies also show that engine control units are able to adequately compensate for the higher oxygen and lower energy content of E15.

The engine performance and durability expectations from the materials compatibility and emission test results are confirmed by studies of fuel system, engine, and whole vehicle durability.

Regulation History of the E15 Partial Waivers Under the Clean Air Act - EPA-420-F-15-044 states that it based its decision on Department of Energy test data. Cars 2001 and earlier were not approved because of insufficient test data.

The EPA claims E15 fuel can be used in...

  • Flexible-fuel vehicles (FFVs)
  • Model year 2001 and newer cars;
  • Model year 2001 and newer light-duty trucks; and
  • Model year 2001 and newer medium-duty passenger vehicles (SUVs).

And it cannot be used in...

  • On-highway and nonroad motorcycles;
  • Vehicles with heavy-duty engines, such as school buses, transit buses, and delivery trucks;
  • Nonroad vehicles, such as boats and snowmobiles;
  • Engines in nonroad equipment, such as lawnmowers and chain saws; or
  • Model year 2000 and older cars, light-duty trucks, and medium-duty passenger vehicles.

The Coordinating Research Council study was flawed.

I found a single study claiming E15 damages engines by the Coordinating Research Council, "Impact of Ethanol Blends On The OBDII System Of In-Use Vehicles".

The DoE responded in a document with the blistering title of Getting It Right: Accurate Testing and Assessments Critical to Deploying the Next Generation of Auto Fuels. They cite a number of basic problems including a too small a sample size, a lack of proper controls, and using known faulty engines.

We believe the study is significantly flawed.

The CRC failed to establish a proper control group, a standard component of scientific, data-driven testing and a necessity to determine statistical significance for any results.

Instead, only three out of the eight engines were tested with straight gasoline containing no ethanol (E0), and one of those three failed the CRC’s test.

No engines were tested with E10 fuel, the de facto standard gasoline for all grades, which represents more than 90 percent of gasoline available in the U.S. market... [No control data for the fuel typically used.]

The CRC also employed a test cycle designed specifically to stress the engine valve train. This test cycle was developed specifically for this study and thus there is no experience base for how to interpret results from the testing. [The test conditions may not reflect reality.]

The CRC used the arbitrary criterion of 10 percent engine leakdown (a diagnostic test in which an engine cylinder is pressurized with compressed air, and the rate at which the cylinder loses pressure is measured) to determine if an engine “failed.” This is not a standard previously employed by either industry or federal agencies during testing, nor as a criterion for any warranty claims. Further, the Energy Department's own rigorous testing has shown that it is not reliable indicator of durability issues.

Perhaps most surprisingly, the CRC decided to select several engines already known to have durability issues, including one that was subject to a recall involving valve problems when running on E0 gasoline and E10. It is no surprise that an engine having problems with traditional fuels might also “fail” with E15 or E20 ethanol-blended fuels -- especially using a failure criterion chosen to demonstrate sensitivity to ethanol and operated on a cycle designed to stress the valves.

Furthermore, the American Petroleum Institute is a Sustaining Member of the Coordinating Research Council raising questions of impartiality.

E15 Is Very Uncommon.

For various reasons, few stations carry E15. According to the US DoE Alternative Fuels Data Center, "E15 is not widely available. It is currently sold at nearly 700 stations in 29 states."

Whether or not it may damage your engine, you are at a very low risk of ever encountering it.

A Word About Warranties.

A common theme in the anti-E15 side is that car manufacturers will not cover fuel-related damage if you use non-approved fuels in your car. This is not the same as claiming E15 will damage your car. I can find no manufacturer claiming they made this decision based on a study. It is, imo, the companies not wanting to risk having to pay for extra warranty repair for a fuel they did not test for.

While the risk of damage does not have data to support it, the risk of warranty trouble by using E15 is real. Whether you'll risk it by putting non-approved fuel into your car is for you to decide. You should check your warranty before using E15.

See Also

Snopes also has a write up on this.

  • great answer - this will get the bounty unless something better comes along (not likely) - nitpick - E15 may be more common than you think - I live in Dallas county - they sell it 1.2 miles from my apartment
    – Zombo
    Dec 31, 2017 at 19:22
  • @StevenPenny Thank you. As for the nitpick, I could have observed there's no E15 near me (I don't know) and concluded it's not common. I'm going to guess you asked the question because you have E15 near you. This is why anecdote is not a substitute for data: selection bias. While I don't have data on E15 stations, a DoE map of E85 stations can stand-in. Note the very uneven distribution and clusters around Dallas and other large Texas cities. Whereas here in Oregon there's only 5.
    – Schwern
    Dec 31, 2017 at 21:20
  • It is more common to see E15 (not advertised, of course) at stations where I live, especially in the summer, where certain blends of gasoline are mandated by state law Nov 23, 2019 at 2:03

At least one source says yes. This is an example for 2014 Hondas:

Fewer than 1% off all cars on the road in North America today are true "Flex Fuel" vehicles.


Filling your Honda car or motorcycle with E15 ethanol blend gasoline will void the vehicle's factory warranty; while eventually damaging your engine and exhaust system.

-"Warning: North America Honda not E15 ethanol 'Flex Fuel' rated", TorqueNews (2014-01-18)

Note: Current Hondas are rated for E15.

  • 2
    This is a neat find! Voiding the warranty along with a manufacturer's warning seems like pretty helpful evidence. For completeness's sake, would you have a source for current Honda's being rated for E15?
    – Nat
    Dec 17, 2017 at 1:26
  • 2
    That article cites no sources to back up its claims. It would be better to cite this AAA article from 2012. It's a bit less breathless only going so far as to note it is not "approved by manufacturers". Claims of damage by the AAA are covered by weasel words like "could", "suggests", "potential". As for voiding the warranty, some say they won't pay for fuel-related damage, others say it might void the warranty. Note that the situation may have updated in the following 5 years.
    – Schwern
    Dec 31, 2017 at 17:31

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .