E15 Ethanol Fuel Can Damage Engines, New Automaker Study Says

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Proposed EPA E15 gasoline pump warning label for ethanol content

Proposed EPA E15 gasoline pump warning label for ethanol content

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A new study released today by the Coordinating Research Council says that E15 gasoline, which contains 15 percent ethanol, could damage the engines of certain high-volume car and truck models.

The two-year study was conducted on eight different engines from the 2001 through 2009 model years, with a pair of vehicles for each engine tested--one on conventional gasoline, one on E15.

The 500-hour durability cycle would be the equivalent of roughly 100,000 miles of normal usage, according to the study's author. It monitored cylinder compression, valve leakage and wear, engine emissions, and emissions-control diagnostics.

Two of the eight engines running on E15 suffered lower performance, misfiring, reduced fuel economy, and damaged valves and valve seats. A third showed tailpipe emissions that increased above the legal limit.

The study was conducted by FEV, a consulting firm that has previously worked for the U.S. Environmental Protection Agency. It was initiated by the Coordinating Research Council, which studies the interactions among petroleum products and automotive equipment and is funded by the American Petroleum Institute and eight automakers.

The EPA conditionally approved the use of E15 for cars built between 2001 and 2009 last year.

Ten separate research papers have now been published assessing the impact of raising ethanol content from E10, which all U.S. market vehicles are designed to accept, to E15.

The CRC accuses the EPA of basing its decision to allow the rollout of E15 largely on a study done by the Department of Energy of E15's effects on the durability of catalytic converters. It says the EPA did not wait for all research to be completed before making that decision.

“Our goal is to ensure that new alternative fuels are not placed into retail until it has been proven they are safe and do not cause harm to vehicles, consumers, or the environment,” said Mike Stanton, president and CEO, Global Automakers. “The EPA should have waited until all the studies on the potential impacts of E15 on the current fleet were completed.”

The Association of Global Automakers is a group of car and light-truck makers whose sales constitute almost half of the U.S. market. Its members include Honda, Hyundai, Kia, Nissan, Subaru, Suzuki, and Toyota, along with sports- and supercar makers Aston Martin, Ferrari, Maserati, and McLaren.

BMW, Chrysler, Ford, General Motors, Mercedes-Benz, and Volkswagen are not members of the association.

What should consumers do in the face of these latest results?

If you own a car built before 2001, don't use E15, period. If you own a car built from 2001 through 2009, you can either avoid E15 or dig into the studies and draw your own conclusions--and watch for further news on the topic.

All automakers strongly suggest that you follow their guidance on choosing fuels for your particular model, which can be found in the owner's manual.

Right now, the discussion is somewhat academic.

At present, virtually no E15 is sold in the U.S. because the so-called blender pumps that will dispense it have not yet been installed.

[UPDATE: This article was updated to correct the list of Association of Global Automakers members.]


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Comments (21)
  1. "one on conventional gasoline, one on E15." Does "conventional" gasoline contain any ethanol? Are they comparing E10 to E15 or E0 to E15.

    I understand the damage to the rubber seals, but I wonder why have valves and valve seats are getting damaged? I assume both are metal. Does the ethanol corrode the metal?

  2. So basically a study initiated by an organization funded by the American Petroleum Institute suggests that only 100% petroleum based fuels are good for your car? Not that surprising I guess.

    Wonder why car manufacturers allow themselves to be dragged into this guerrilla from Big Oil against newcomers on their turf. Seems rather hypocritical since it takes only very low costs modifications to make their products not just E15 but E85 compatible.

  3. @Chris: The automakers' concern is that they will be blamed for any damage caused by E15 usage in vehicles that were never designed for it--and in fact were engineered long before E15 was even conceived of.

    I need to check into whether 2010 and later vehicles are engineered to accommodate E15. But IMHO, it's a valid concern that if an otherwise serviceable, low-mileage 2006 vehicle incurs some kind of damage from E15 use, its owner will blame the automaker for something it didn't design for.

    That said, running for 100,000 miles exclusively on E15 would be virtually impossible today and for at least a few years to come, since the fuel hardly exists today.

  4. @Chris: Re/E85 compliance, I've heard that the cost to automakers is roughly $100 to convert an engine to accept the more corrosive E85 fuel.

    All during the 2000s, they got extra CAFE credits for selling Flex-Fuel vehicles even if the buyers had no idea they could handle E85.

    And of course the vast majority of those vehicles never used a drop of E85--but the $100 cost was the cheapest, easiest way for automakers to get their CAFE averages to where they needed to be. That provision of the CAFE laws is now going away, finally.

  5. @John Voelcker: I don't understand. Automakers were encouraged to make their cars E85 compliant at very low cost so they wouldn't have a reason to whine about possible damage to their vehicles once ethanol based fuels became more widely available; now that provision of the CAFE laws is now going away but with the "finally" remark you suggest that's a good thing somehow?

  6. @Chris: We've already seen 1 boom-and-bust cycle in domestic corn ethanol production. Biomass ethanol is progressing far more slowly than predicted. And Congress killed all ethanol subidies:

    Now, at least one study says that we simply can't achieve legally mandated amounts of ethanol in our fuel:

    Since E85 vehicles produced CAFE credits for NO net improvement (since the vast majority did not & will never use a single drop of E85), it seems sound policy.

    My 2 cents after covering it.

  7. @ John Voelcker: So....you often seem skeptical about BEV's in general and Tesla's in particular and now you sound skeptical about bio fuels too...Sorry John, but it's increasingly unclear to me why you chose to write for a green car blog.

  8. @Chris: I'm a journalist, not an advocate. If you want advocacy, there are many fine sites produced my uncritical advocates.

    I report the news, but I try hard not to do so uncritically or without context. Many, many outlets regurgitate press releases without adding any value. If you prefer that, there are many sites that take that approach.

    At the risk of sounding sanctimonious, there are no easy, cost-free answers. We try to add context and a sense of the challenges around all of the possibilities that present themselves as "green."

    We think of it as reality. Again, my 2 cents after doing this for a while.

  9. @ John Voelcker: I am not looking for advocacy, but critical thinking/adding context/value has of course a lot to do with adding your own opinion which I feel is sometimes based on misconceptions on your part or on opinions of industry experts who may have agendas that are somewhat broader than just finding the truth or are just not that good at what they do, just parroting the opinions of actors in the industry with agendas of their own. The buck just doesn't stop at expert opinions...

    My 2 cents would be: the more agendas of money and power are involved (and when it comes to new energy vehicles they really are huge)the more important it becomes to have the right sort of critical attitude to determine what exactly is "reality".

  10. There are more comments in this thread
  11. yes and the oxygenation also contributed to phosphorous build up in the entire fuel system , partially due to the reaction(s) from the metals

  12. And by the bleeping way, With Ethanol supplying 10% for the fuel for the country, would it kill you to admit that it has achieved something of value (along side the negative context that you rightfully provide.)

  13. @John's 'I'm a journalist...' post. You're more of an advocate than a journalist with articles here. A journalist would cover all sides of the argument, and still maintain one's critical stature. However, you bought the entire “study” and failed to mention the eighth motor, on gasoline, failed its tests, which would have brought into question the strength of the “study”. “A third showed tailpipe emissions that increased above the legal limit.” is indicative of withheld information by those conducting the study and the limited knowledge base of the one covering the story.


  14. Setting the studies aside, my experience with ethanol fuels (10%) has been bad. My small engine motorcycles run poorly. The plastic tank and cap on my chainsaw swell together so you need pliers to remove the cap. Carburetors have fused themselves together after sitting (a white powdery corrosion where non-ethanol fuel will simply get gummy). I have not melted any fiberglass tanks because I'm smart enough not to pour ethanol in them. Reverting to non-ethanol fuels has solved these problems. Not scientific, but you can't accuse me of having a financial benefit connected to my conclusions either.

  15. No, but I can accuse you of having vented-to-air tanks; cars don't. Cars were changed to accept alcohol blends for oxygenation back in the 80's. Small engines (two strokes) as well marine engines never made those changes. Maybe they will but of yet, no.

    Before there was gasoline / petrol, there was alcohol.


  16. Yeah I know, but if the fuel is mandated into existence, then I lose because I'm not driving a car from the 80's. I'm all for developing new fuels and systems to run them; the mandate is the problem for me. Before there was Ethylene Glycol/Water, there was alcohol.

  17. E10 is already destroying small engines all over the country. Think of the environmental waste created by constantly throwing out small weed wackers and small push mower/lawn tractors, snow blowers etc... Please someone with some common sense stop this non-sense. I am all for alternatives but they have to work better not worse.

  18. I believe the environmental impact of adding ethanol to gas is not as positive as many would like us to believe. I give you the example of my 2012 Jetta. Using regular (10% ethanol) gasoline my car gets only 27 mpg around town. When I use premium (0% ethanol) my car gets 34 mpg around town and it runs and idles much better. All the proof I need is from my own pocketbook and gas mileage log.

  19. In this discussion re benefits, if any, of E85, most are still ovverlooking the detrimental consequences of using E10, or for that matter, any ethanol-based fuels. Here's some past history from 2005 and later:

    Three things bust the ethanol bubble. It's expensive to get ethanol to the pump. A gallon of ethanol is only 65 percent as efficient as a gallon of gasoline. A 10 percent blend of ethanol in gasoline degrades the fuel, reduces fuel mileage and over-extended use, creates sludge in the fuel tank and corrodes fuel pumps, carburetors and fuel injectors.

    alternative fuels burn more energy than they produce. Researchers say t takes 29 percent more fossil energy to turn corn into ethanol that the amount of fuel theprocess produces ...

  20. It seems these Ethanol "studies" are NOT looking at what happens to fuel tanks when E10 blends are left sitting in parked vehicles for extended periods. I own two recreational vehicles that are rarely driven. When I tried to start one after 14 months in storage, I found the E10 fuel had separated into alcohol and WATER, and the water had RUSTED the fuel pump and tank. My repair cost will be over $300 for parts alone. I have also replaced two lawnmower carburetors in the last 12 months because they became clogged with heavy deposits after being stored with E10 blend fuel. I have been forced to start using additives to counteract the effects of Ethanol in my stored vehicles and equipment, and I wish the government would make Ethanol illegal.

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