The People of America's Oil and Natural Gas Indusry

Study: E15 Could Put Some Engines at Risk

Mark Green

Mark Green
Posted May 18, 2012

More on the potential risk to America’s car and truck fleet posed by E15 – gasoline containing 15 percent ethanol that has EPA approval: Just-released research indicates that more than 5 million existing cars and light trucks, which EPA says are OK for E15 use, could develop engine problems as a result.

Why this discrepancy?  The Coordinating Research Council (CRC), a non-profit entity supported by the automotive and oil and petroleum industries, tested the durability of engines using tests that have been conducted for more than a decade to determine how well engines would hold up with a new fuel. 

On the other hand, the Department of Energy (DOE) and EPA tested the catalyst system and then used the results of those tests to say the engine would be fine.  It’s a bit like taking a reading test to determine whether your heart is healthy.  

A key finding in the CRC study:

  • Of eight different tested engine types, one had a design that was (in retrospect) inappropriate for the test cycle, two failed on E20 (20 percent ethanol) and E15, and five passed on E20 and by assumption E15 and E0 (gasoline with zero ethanol content). The two engine types that failed E15 testing successfully completed reference testing on E0.
  • The majority of the failures can be linked to issues with valve seats, either related to material or wear/deformation.

There are at least 5 million known engines on the road today with the same or similar characteristics to the two engines that failed on E20 and E15. Because testing was done on only a small proportion of the light-duty engine types currently in use, the number of at-risk engines probably is higher.

API President and CEO Jack Gerard, during a conference call with reporters this week:

“EPA’s decisions in 2010 and 2011 approving E15 ethanol-gasoline blends for most American vehicles were premature and irresponsible. … Worse, as API noted in its press briefing two weeks ago, it approved the fuel even though government labs had raised red flags about the compatibility of E15 with much of the dispensing and storage infrastructure at our nation’s gas stations. … Not all vehicles in the CRC tests showed engine damage, but engine types that did are found in millions of cars and light duty trucks now on America’s roads.”

Mike Stanton, president and CEO of Global Automakers:

"We can build the cars for the fuels, but the EPA made this retroactive to 2001 and that is the problem. … 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. The EPA should have waited until all the studies on the potential impacts of E15 on the current fleet were completed."

Mitch Bainwol, president and CEO of the Alliance of Automobile Manufacturers:

“The study… indicates the risk for consumers is profound, with clear environmental, safety, fuel efficiency and financial implications.  Cars were not built for E15. It’s that simple – and now we have material evidence that validates our concerns.”

Not surprisingly, the CRC study doesn’t sit well with some folks.  A DOE blog criticized the CRC study’s methodology rather than focusing on the identified risks and concerns for consumers.

First, DOE seems to think that it has more expertise than the car designers and manufacturers who conducted the CRC tests.  CRC has been doing work of this kind for more than 70 years, often with DOE’s funding. Even more interesting: Through the National Renewable Energy Laboratory, DOE was an active participant in the technical oversight panel for the CRC study throughout its duration and at no point raised any concerns. Other points:

  • Valvetrain-type engines that were tested were selected from among popular 2001-2009 models, not cherry-picked for failure. Indeed, five of the engines that were tested passed the E20 test. If someone was trying to pick engines that would fail testing they did a pretty poor job of it. 
  • The engine pass/fail determination was made after engine teardown and analysis.  The use of the 10 percent cylinder leakage criterion to determine whether there may be engine distress is a well-established and accepted industry standard used in engine development and was used as a signal that teardown was required.    The CRC study indicated use of E15 would damage the valves in some engines, leading to cylinder leakage, loss of compression and power.
  •  Nobody should be all that surprised that DOE found no discernible impact of E15 based on teardown inspections of engines used in its catalyst durability study.  After all, its study was just that – an evaluation of the effects of higher levels of ethanol on a catalyst (i.e., the catalytic converter).  It was never designed to specifically assess the stresses of mid-level ethanol blends on an engine.  For DOE and others to draw conclusions about the effect of ethanol on an engine based on a test designed for a catalyst evaluation is not only scientifically unsound, it is just plain wrong. 

See a more detailed rebuttal of DOE’s comments, here.

E15 is a perfect example of why the Renewable Fuels Standard is becoming unrealistic and unworkable. EPA made a rushed and premature decision to meet a political deadline in the fall of 2010.  The CRC research shows that EPA didn’t do its homework and is willing to put the consumer’s vehicle at risk. EPA needs to base its decision on sound science, not political goals.  The auto and oil industries conducted a scientifically sound and robust study, and the results from the CRC study should be concerning.


“The value of these vehicles along with the value of vulnerable gasoline dispensing equipment at the nation’s 157,000 gasoline service stations could run into many billions of dollars. EPA’s waivers put these investments at risk. The result could be more vehicle repairs for consumers and upward pressure on gasoline prices. … This is breakthrough research that should’ve been done by EPA. … Our data needs to be looked at.”


Mark Green joined API after a career in newspaper journalism, including 16 years as national editorial writer for The Oklahoman in the paper’s Washington bureau. Mark also was a reporter, copy editor and sports editor. He earned his journalism degree from the University of Oklahoma and master’s in journalism and public affairs from American University. He and his wife Pamela live in Occoquan, Va., where they enjoy their four grandchildren.