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E15 ethanol fuel can damage auto engines - study

05.16.2012  | 

Compared with typical gasoline, issues include damaged valves and valve seats, misfires, lower performance, engine damage, poor fuel economy and increased emissions.


Auto repair costs for consumers could rise due to adverse effects of fuel containing 15% ethanol blends (E15), according to new results from a two-year study on engine durability.

The study was conducted by FEV, a longtime consultant to the US Environmental Protection Agency, on behalf of the Coordinating Research Council (CRC).

The CRC study released Wednesday showed adverse results from E15 use in certain popular, high-volume models of cars, its authors said.

Problems included damaged valves and valve seats, which can lead to loss of compression and power, diminished vehicle performance, misfires, engine damage, as well as poor fuel economy and increased emissions.

“Clearly many vehicles on the road today are at risk of harm from E15. The unknowns concern us greatly, since only a fraction of vehicles have been tested to determine their tolerance to E15,” said Mitch Bainwol, CEO of the Auto Alliance trade group.

“Automakers did not build these vehicles to handle the more corrosive E15 fuel. That’s why we urged EPA to wait for the results of further testing.”

The potential costs to consumers are significant, the study says. The most likely repair would be cylinder head replacement, which costs from $2000-4000 for single cylinder head engines and twice as much for V-type engines.

“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, CEO of the Global Automakers trade group. “The EPA should have waited until all the studies on the potential impacts of E15 on the current fleet were completed.”

“Automakers believe that renewable fuels are an important component of our national energy security, but it is not in the longer term interest of the government, vehicle manufacturers, fuel distributors or the ethanol industry itself, to find out after the fact that equipment or performance problems are occurring from rushing a new fuel into the national marketplace,” added Bainwol.

Growth Energy, an ethanol industry trade group, petitioned the EPA in March 2009 to raise the limit on ethanol in gasoline from 10 to 15%.

In June 2008, EPA outlined testing needed for the agency to approve a waiver, and EPA requirements were consistent with test plans developed by the auto and oil industries.

The CRC, composed of engineers from the auto and oil industries, was working with EPA and US Department of Energy (DOE) on a multi-year suite of tests on the effects of higher blends of ethanol, according to the trade groups.

This testing included more than $14.5 million of research sponsored by the auto and oil industries, and $40 million of testing sponsored by the federal government.

Before those tests were completed - in October 2010 and January 2011 – the EPA granted “partial” waivers to allow the introduction of E15 into the marketplace for use in model year 2001 and later vehicles.

EPA’s decision was based largely on a DOE study of the effects of E15 on durability of catalytic converters, the primary pollution control system in a vehicle

EPA did not undertake or wait to consider the results of this engine durability test, or for other E15 related research still underway, the groups allege.

The CRC study took duplicates of eight different vehicle model engines spanning 2001-2009 model years. All 16 vehicles were tested over a 500-hour durability cycle corresponding to about 100,000 miles of vehicle usage, the authors said.

A range of engine operating parameters was monitored during the test, including cylinder compression, valve wear, valve leakage, emissions and emissions control system diagnostics.

Two of the engines tested on E15 were said to have mechanical damage. Another engine showed increased tailpipe emissions beyond the allowable limit.

More details on the study can be found at the Global Automakers' website by clicking here.

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Lige Spiegel

If you're going to make the average american pay for supid fuels like this one and pay for expensive car repairs like u said above y don't u make a deal with the trucking companies to use biodiesel instead forcing the average american in paying for expensive car repairs. Because biodiesel can work in (any) diesel engine expect when it gets pretty cold outside but i think more reseach should go into anti-gel additives for biodiesel instead robbing the average american blind especially in this crazy economy we're right now. because we use diesel alot for moving things in big heavy amounts like an example(Sam's Club,car dealerships,most trash trucks,trains,some rvs', some buses especially school buses,and ships) just to name a few. Also cheaper to make less waste from vegtable oil and other oils like lar,less depences on foreign oil,can work in (any) diesel engine,of course it will make the oil companies mad but just think how much it would save the states in school fuel costs. Also when ever we export something by ship we can ask if they have any waste vegtable oil they are willing to give away and knock two birds with one stone and it will reduce the amout of farmland we need to grow are own oil.



Charlie Peters



I wonder what fuel the "control" fuel was in the study, and what engines were used... if they didn't compare the same engines to E10 then something doesn't sound right. 500 hours also seems like a pretty aggressive cycle to accumulate and equivalent 100, 000 miles (average speed 200 mph?).

Bob H

Have a 2007 Corvette. Last year I had to replace all of my gas tank sensors, seals, gaskets, and components. Reason 10% Ethanol. After that I found out that on outboard engines, engine driven yard tools and other small engines, that if you run any ethanol at all, it will void the warranty on that equipment.

Rob Briggs

Too many non-specifics to be a useful report. Lots of use of "could", "can", "might", and the like. Nothing definite.


Hmm... 500 hours and 100,000 miles. What normal car can travel for 100,000 miles at 200 miles an hour? Any vehicle would experience engine failure at that rate.

ron bolin

speedway also has ethanol

Miro Kefurt

If engines have problems in 500 hour test, which most engines pass easily, then for sure they will have problem in 3,000 to 4,000 hours of real life driving over 100,000 miles as the real average speeds for most vehicle owners living in urban and sub-urban areas are will under 25 MPH.
The "stress test" assumes that same wear will occur in 100,000 miles but there is absolutely no substitute for 10 to 12 years or real 100,000 to 120,000 miles or actual use.
So when 500 hour test comes up with "problem" the real life problem will be by at least a magnitude greater !

Carl Westhoff

I do not know the protocol for these tests but I can counter them with not a sample but with the entire population of the brazilian fleet of cars, that are running at least for 60 years on a gasoline/ethanol blend, sometimes as high as 25%.
Of course HYDRATED ethanol is corrosive. I personally had that experience: I run 330 thusand kilometers between 1985 and 1998 with an 100% ethanol fueled car with no compression losses, no oil consumption in the 4 cylinder 12:1 compression ratio water cooled VW engine. The only extra cost were 2 carburettors that corroded in the period, but even that problem is now solved with SS steel fuel injection pumps.
On the other hand emissions from the gasoline/ethanol blend have less CO and unburned hydrocarbons.
I can only suggest to the CRC people to come to Brazil and look for themselves.


It's high time that all ethanol subsidies be eliminated.


Any crop based ethanol is a mistake. Increased food cost, reduced mileage, etc. In addition we fertilize corn w/ammonia which is usually made from natural gas.


EPA: "oops"

Gustavo Heins

before to use any gasoline mix it is necessary to finish all test


Another Fed blunder. Legal Class Action will be in order if numerous repairs begin as a result of this oversight. Keep us informed.

You may also research and provide the facts regarding each vehicle manufacturer's fuel recommendations are and were over the past 15 years.

Terry Evans

There appears to be an error regarding the 500 hour durability test. How does this correspond to 100,000 miles?

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