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Will 15% ethanol damage my engine?

I have a 2008 Honda Civic that doesn’t like the 10% ethanol now available. I have heard that the new 15% blend will damage my engine and emissions system. Does anyone have any hard facts on this? Can you point me to a study or some research that shows the damage that 15% blend can cause?

Read the owner’s manual. It will tell you how much ethanol your Civic can tolerate.

I’m not aware of any 15% ethanol currently for sale. There’s talk of this in the future, but there’s no E15 available where I live.

What do you when you say your Civic “doesn’t like the 10% ethanol now available?” Both of my cars run equally well on E10 or straight gasoline. The only difference is the fuel mileage, which is lower with E10.

E15 is being proposed, discussed, and studied. It is not for sale yet. A 2000 car likely won’t do well with E15. If and when it comes on the market E15 will not replace E10 which will continue to be available.

The distribution of gas with no ethanol at all could be reduced, and it is already hard to find in most areas.

I have a 2008 Honda Civic that doesn’t like the 10% ethanol now available.

What does that mean? Do you mean your fuel economy isn’t as good with E10, or are you experiencing some kind of problem you attribute to using E10?

Perhaps there is something wrong with your 2008 Civic. My 1998 Civic runs on E10 just fine.

The jury is still out on what effect E15 will have on engines. Preliminary tests conducted by GM on their engines showed problems in 50% of the engines tested. These ranged from the engines running hot, damage to the catalytic converters, and damage to cylinder walls of the engines.

When Minnesota mandated that E10 be the primary motor fuel sold in 1992, and even after warnings from the auto manufacturers about the use of E10 in their engines, it resulted in damage to engines that were never designed to run on E10. When Minnesota was threatened with a class action law suit for mandating a motor fuel that caused damage to personal property, the state then allowed gas stations to sell gasoline that contains no ethanol. And we can still purchase gasoline without ethanol.

So if past history is an indication, and the automakers aren’t given enough time to test the effects of E15 on their engines, it’s the vehicle owner who ends up being the guinea pig at their expense.


With the 10% ethanol, the engine idle is not as smooth, and the mileage goes down about 12%. Also, there seems to be a slight loss of power. When I use “real” gas, these problems disappear.

It sounds like you might be having problems with your EGR valve or your knock sensor. The symptoms are more noticeable when you use E10, but I believe there is another cause. Your engine should be able to handle E10 without any problems.

The changes are slight. The mileage drops from about 40mpg to 35/36 mpg. The reason that I notice the changes is because the performance is so good with “real” gas.

E15 has, as of last week, now been approved for all cars model 2007 and newer. It’s being recommended by the EPA that the stations switch over, but it is not mandatory, and it may be awhile before E15 becomes common. If the public doesn;t want the product, the feds will ultimately have to find a way to provide economic incentive for the stations to switch over. Like perhaps fines or penalties.

I’d suggest that you Google “problems with E15 fuel”. You’ll find numerous articles from reputable organizations discussing the subject.

This is from the owner’s manual:

Some gasoline today is blended with oxygenates such as ethanol or MTBE. Your vehicle is designed to operate on oxygenated gasoline containing up to 10% ethanol by volume and up to 15% MTBE by volume. Do not use gasoline containing methanol.

This is from the owner’s manual:

Some gasoline today is blended with oxygenates such as ethanol or MTBE. Your vehicle is designed to operate on oxygenated gasoline containing up to 10% ethanol by volume and up to 15% MTBE by volume. Do not use gasoline containing methanol.

Either use what Honda recommends in the manual or contact American Honda and see if they have an update. BTW, Honda states that fuels with up to 10% ethanol and 15% MTBE are acceptable on their web site. Contacting them will likely get the same answer.

Ethanol does reduce mileage and I have heard it damaging engines on other sites. Mostly what I have heard is that it kills fuel pumps. It does not have the same lubrication properties as gasoline. It is a price subsidy for farmers and a bad thing for the enviroment, not to mention consumers. It causes fuel prices to rise and food prices to rise. If they used a non food crop and land that was not good for crop production, then maybe it might be better, but it takes more oil to produce ethanol and ship ethanol then you get. It is cheaper to drill and process oil and you get real gas.

Coincidentally, I was having a discussion with a tech from a Honda dealer last evening. He was saying he was looking at “moving on” becuae he has too much “downtime” and is getting frustrated. I said to him “don’t worry…you’ll be plenty busy soon. E15 is here”. He just moaned and rolled his eyes skyward.

Imagine, if E15 gets forced on us, the long lines at dealer service departments of people demanding to know why their mileage has dropped.

For those who think it can’t get forced on us, I suggest thst the feds are experts at providing economic incentives for private industries (and even individuals) to do what they want.

Imagine, if E15 gets forced on us…

Imagine if someone pries your eyelids open and makes you watch violent images on a screen, like in the movie A Clockwork Orange. That would be even scarier, and might be just as useful as imagining other things that aren’t likely to happen!

Wow. Did I touch a nerve?

I’ll bet a breakfast that E15 will become normal within the next year, and not due to consumer demand. I hope I’m wrong.

No, I don’t think you touched a nerve. It’s just that this whole thread seems to be, in my opinion, an over-reaction to an EPA recommendation that would have to go a long way to become a mandate.

I think I am pretty moderate, and even I would be pretty P.O.ed about phasing out E10 in favor of higher ethanol concentrations. I am confident proper testing will put a stop to this bad idea. My car is 12 years old, and I don’t think it would do well on E15. In this economy, there are a lot of people driving older cars who can’t afford to replace or retrofit them.

I think Obama is smart enough to learn from history, and this kind of mandate would be as harmful to Democrats as the assault weapons ban was for Clinton-era Democrats. It isn’t in the Democratic Party’s interest, unless they are trying to get Republicans elected. Obama has already failed to deliver on several important campaign promises, so nobody will notice if he backs off on this issue.

I hope you’re right.

Actually, according to USA Today, this approval was pushed through by a cohort of 34 ethanol producers and their lobbyists. They’re also continuing testing on pre-2007 vehicles with the expectation of approving E15 as a motor fuel for those as well.

I am definitely no fan of Obama’s, but I’m satisfied by the USA Today article that this one had other origins. Hopefully Obama won’t try to use this approval as a campaign point and do what a fear, find a method of economically encouraging gas stations to switch to E15. I emphastically agree that this would be unfair to those millions of people who drive older vehicles and cannot afford to buy a new one, and these same people are the reason I don’t think it could develop a significant consumer demand. The moment they started having problems and/or saw their gas mileage drop they’d go elsewhere to a station tha still carried E10.

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