Ethanol mess with your car’s engine? You may be on your own


The ethanol industry is getting a rare run for its money in Washington in recent weeks as a number of lawmakers try to repeal the many tax breaks the fuel additive has received for years.

This has traditional critics of the industry stepping up their game, including the Environmental Working Group. The nonpartisan nonprofit has issued reports critical of ethanol in the past, and is weighing in this week with one that looks at concerns about the impact of ethanol on engine maintenance.

The EPA recently approved an increase in the amount of ethanol that can be blended with gasoline from 10 percent to 15 percent. There’s been some  concern that more ethanol will create added performance and maintenance issues with gasoline engines, however, and that car makers won’t honor service warranties if problems are traced to E15 problems.

So EWG called the U.S. headquarters of 13 major automakers (posing as regular consumers) and asked where the car companies stood on E15 and engine warranties.

Here’s a summary of their results, based on conversations with company reps:

Four companies said warranties would be voided if E15 caused engine trouble:

  • Lexus suggested using premium unleaded fuel with an octane of 91 or higher. Since E15 is not listed as a recommended fuel in its owner’s manuals, the warranty would be voided if using E15 caused engine problems.
  • Subaru said a vehicle’s warranty could be voided if an engine problem were traced to using E15. Subaru’s representative noted that some people recommend against higher ethanol blends.
  • Toyota noted that their owner’s manuals explicitly state that the warranty is only valid for blends up to E10, except for its limited number of flex-fuel vehicles.
  • Volkswagen’s representative suggested calling a local dealer but said that warranties would be voided if an engine problem were traced to the fuel.

Other companies gave answers that were more vague:

  • BMW referred consumers to a local dealership.
  • Dodge’s representative had not personally heard of E15 before. Instead, EWG was referred to a local dealer and EPA’s website, which provides no information by car makes or models.
  • Jeep’s representative said using E15 in vehicles manufactured after 2007 should be fine, but that there are concerns with vehicles that fall in model years 2001 to 2006 . The company recommended checking with a dealership to see if the difference between E10 and E15 would matter for a particular vehicle, and also suggested referring to the owner’s manual.
  • Honda’s representative said only E10 is covered by the warranty in the owner’s manual and there is a good likelihood that it would be voided if a higher ethanol blend were used. It, too, recommended checking with a local dealer.

Some companies said they knew nothing about E15 and only had information about E85, or referred to the cars’ recommended octane level:

  • Ford’s owner’s manuals say its vehicles should not use fuel with more than 10 percent ethanol. A representative mentioned that a few weeks prior, a customer had engine trouble after using 20 percent ethanol (E20) and warned that gaskets and seals can wear faster with the higher blends.
  • Saturn’s representative was not familiar with E15 but mentioned that E85 can only be used in flex-fuel vehicles, and that its cars are made with yellow gas caps to signal compatibility with ethanol fuel.
  • Buick said it does not make vehicles that are compatible with E15 and only had information on E85 and its use in flex-fuel vehicles. In the end, 87 or higher octane fuel was recommended.
  • Nissan’s representative confirmed that E15 is not mentioned in the owner’s manual and instead recommended using a fuel with 91 or higher octane content.

One company said its warranty would not be voided with E15 so long as the correct octane level was used:

  • Chevrolet’s representative indicated that owners should use regular unleaded gasoline of 87 or higher octane to avoid heavy “knocking.” The vehicle warranty would not be voided as long as that condition was met.
Tom Fowler

25 Responses

  1. walt says:

    Apparently they aren’t happy with starving a few people – they want to starve more. When the ag farms switch to corn for ethonol a lot of people go hungry.

  2. TransAmer99 says:

    @JB: No, you have your numbers reversed. E85 is 85% ethanol and 15% gasoline. Look it up. That’s why you have to have a “Flex Fuel” designation from the auto manufacturer to use E85. There is no such designation for the use of upto 10% ethanol, which was recently legislated to increase to E15. Nonetheless, the deterioration of rubber fuel line components in older cars as well as the fewer BTU’s/gallon of ethanol blends over gasoline are well documented.

  3. Adler says:

    Does anyone remember the real reason for ethanol in gasoline? Remember the EPA mandated, you know imperial dictate, the use of MTBE as an oxygenator in gasoline sold in areas with air quality problems. Then low and behold, they found that leaky underground tanks were polluting ground water. So instead of ordering the tanks to be repaired or replaced, they dictated that we use ethanol as the oxygenator, and then sued the companies for using the MTBE the EPA had previously dictated.

    Ethanol was never supposed to be a fuel source.

    Guess what? Ethanol and MTBE both have the properties that allow gasoline and water to mix.

    The EPA and ethanol are nothing but a scam foisted on us.

  4. mrsrandom says:

    So if we use gas with too much ethanol the car warranty is voided. But we don’t exactly have a choice do we? Where’s the ‘no ethanol’ gas stations so I can avoid this problem? Yep, that’s what I thought. Ugh.

  5. Ringo says:

    My bet is on Ethanol; the U.S. gov’t history of bad decisions or decisions specifically directed at shafting the public is long and active. And the agenda is pretty obvious; push up ethanol content and force people out of their favored vehicles into crappy commie clown cars the size of the Smart car. The other piece of the agenda is to limit mobility as much as possible such that out-of-town travel becomes prohibitive unless you take the new gov’t run trains after the gov’t goons molest your wife and kids in the security shack. Americans, your future is dim indeed.

  6. steve says:

    there are millions starving in the world and we are putting corn in the gas tank, this is tarded-re…it is not as efficient as pure gasoline and will decrease mileage…why would you want to put this in any gasoline powered motor…

  7. Krystyna says:

    The government & it’s lobbyists do not care one smidgen if our cars wear out early or even break down over the use of ethanol in gas. Did anyone ever tell us about the perils of using ethanol gas in our small engine tools, like chainsaws & lawn mowers? Heck no! I never heard anything about ethanol eating up rubber parts in engines until I overheard two old timers at a store talking about it. My husband & I have been through two push mowers, a couple of chainsaws & a handful of weed eaters before we figured out what was going on. Thank God we moved to a rural area, because up here, ethanol containing gasoline is the exception, not the rule. Word has gotten out around these parts that ethanol is bad, and people stopped going to gas stations that had it. So, most of them dropped ethanol gas & started putting up banners that said “no ethanol!”. I just feel sorry for you folks down in the Houston area. Because ethanol gas is all the government will allow you to have!

  8. pdh42 says:

    What Nobama and his EPA henchmen are doing to us is making us buy the “green” cars of their choice by forcing this ethanol crap further down our throats….. What is amazing about ethanol is that it is energy negative and yet people “think” that it is helping us…. What is sad is that so many people believe them….

  9. Reality_Sets_In says:

    “Filling up with higher ethanol blends could void your car’s warranty.”

    Like we really have a choice? Government says what we put in our tanks. If it contains up to 10% ethanol, the gas its self should be 10% cheaper!

  10. MichaelHenley says:

    Incidentally, the owner’s manual for my 2010 Mazda says, using more than 10 percent ethanol will void the warranty. I’m sure our lobbyist owned government will cover me when my car goes bloooey on E15. -wan smile-

  11. MichaelHenley says:

    JB – E85 is eighty-five percent ethanol, NOT 85 percent gasoline.
    E15 would mean 15 percent ethanol, although I’m not sure that term is in use.

    In any event ethanol, especially corn based, is a bigger boondoggle than Madoff. We even PAY them 50 cents per gallon subsidy to make the stuff.
    We’re like the prostitute providing the ‘service’ then paying the ‘John’ for the honor.
    Always remember, ‘GREED IS GOOD’ is the death knell of free enterprise.

  12. JB says:

    There is no such thing as E15. Gasoline motor fuel that is 15% ethanol and 85% gasoline is E85.

  13. Rez says:

    Ethanol also reduces your fuel mileage. It’s pretty much a lose-lose for everyone except the Iowa farmers and their politicians.

  14. Observer says:

    Ethanol has been a scam from the word go.

    The press reported recently that an estimated 40 percent of the corn harvest is now dedicated to the production of this heavily subsidized “alternate energy.” Given the enormous subsidies and tax breaks the agri-businesses and processors enjoy from this central government action to not only pick winners and losers, but in fact to put competitors at as much disadvantage as possible, Americans should be made aware of this federal government underwritten threat to the energy sector and national security.

    But very much more important is the threat to the environment which we now are witnessing in the form of the vast flooding of the Mississippi water shed and its tributaries as it makes its way to the Gulf. (May God help the citizens of New Orleans!)

    The fact of the matter is that after spending billions since the days of FDR to observe improved conservation practices and place marginal land in “Soil Banks”, one of the results of the ethanol market distortion is to encourage fence row to fence row cultivation once again and the destruction of water holding native grasses and trees. The current failure to hold snow melt and rain results, among other things, in loss of irreplaceable topsoil and possible jeopardy of America’s future generations.

    So one innocently asks where are the in depth studies on the environmental impact done by the ethanol industry along with the critical vetting of such statements by our many review boards and EPA strike forces?

    In the case of Macondo the press was like some sort of lynch mob and the Environmentalists have been making their living from this brouhaha; yet they ignore their work in promoting ethanol and all its evil results.

    The possible silver lining to this current and impending catastrophe is the flushing and cleansing effect that this enormous volume of “fresh” water is likely to achieve in the Louisiana wetlands but this good will be offset by the insecticides and excess nitrogen from corn, etc, production which will surely substantially widen the “Dead Zone” in the Gulf as it has been doing for some twenty years or more.

    So let’s hear it from the environmentalists and crusading media reporters. Ethanol subsidies in all forms from quotas, tariffs, to payments to Big agri-businesses should be stopped now.

  15. TC says:

    I’ve wondered for some time what the ethanol does to my car, besides the lower gas mileage. I’ve had some problems with my check engine light and I noticed that it goes off when I fill up in Louisiana which as far as I can tell (no WARNING MAY CONTAIN ETHANOL! sign) doesn’t use ethanol in their gas and magically my light turns off, and of course I get much better gas mileage.

  16. Joe says:

    E15 is not as bad as the new ultra low sulfer diesel. My truck’s performance and fuel milage has gone to pot since this crap was introduced.

  17. Paul says:

    The fact that some of the manufacturers are saying “Ask a dealer” doesn’t exactly inspire confidence. Wouldn’t you think the people who designed and built the vehicle would know what fuel it needs, and what might harm it? Maybe it’s just CYA.

  18. db64 says:

    Car companies love ethanol because ethanol wears down engines faster thereby forcing us to buy cars more often. Of course warranties will not cover something that benefits car manufacturers.

  19. Why quibble or rearrange chairs on the Titanic? You guys are VERY late with your discoveries on ethanol’s downsides– Now why not face the real peril that years of public subsidy sloshing into ethanol coffers may well have enabled them to BUY (i.e. corrupt) more than enough votes in Congress and the Executive Branches to keep this scam going despite the growing outcry.

    Check out the Ethanol Transparency Project (ETP) at

    Help make a difference while you still can.

  20. Jeremy says:

    So does this mean the Feds pick up the tab for repairs or do the corn state welfare farmers pay?

  21. Commrade_Leftist says:

    Who cares as long as the corn states get theirs, right? I’d pay extra for 100% gasoline to avoid ANY ethanol.

  22. Matt says:

    Ethanol will eat through gaskets. It also burns hotter and will greatly reduce engine life. There is NO positive to ethanol.

  23. Dollar says:

    My marine dealer told me to not use ethanol in my Yamaha outboard, or if do , to use an additive made by Stabil especially for marine engines.

  24. Mark from Louisiana says:

    A friend of mine with a BMW that was under warranty had a fuel pump fail. They pulled a fuel sample from his tank, his was ok, but if he had more than 10% ethanol in his tank, his warranty would have been voided on the fuel pump.
    The dealer recommended that he only use “top tier” gas stations and to keep a record of all fill ups so that if in the future his gas tested for too much ethanol, he would have records to prove where he bought it and then the station/distributor would be on the hook for repairs.

  25. meetwoodflac says:

    Ethanol will destroy rubber over time. Rubber fuel lines are rare in modern cars, but many cars that are not too aged have rubber components in fuel handling chores, particularly between the tank and the fuel pumps.