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Ethanol Content in Gasoline

My concern today is about the percentage of ethanol added to gasoline, up to 10% Ethanol Content is what most gas pumps display, and have for a number of years. The latest, which I've heard on the radio, is that the ethanol content may be as high as 15% by this Summer. My pickup truck is an '02 Chevy Silverado 1500, ten years old, and I always thought that the "up to 10% ethanol" gasoline wasn't a big deal for a vehicle built within the last decade; every 2-3 tankfuls (34-gallon tank, never gets below 1/4), I add a can of "Sea Foam" to treat the gas. I also have 47,000 miles on the truck, drive it 3-4 times a week and only when I can justify using it, and keep it in my garage when not using it. A talk show host I was listening to this morning said that the ethanol was especially bad for older vehicles and older engines (not that I consider 10 years to be "old"), and that ethanol gas was just bad in general. One of the callers to the show said that having a vehicle sit too long with 10% ethanol gas could cause seals to dry out; I'm wondering now if I'm giving my truck enough "exercise" by limiting my usage of it to 3-4 times a week, and should I open the garage and let the engine run for a few minutes on the days I don't use the truck for transportation? I like this truck and I intend to keep it for a long time, so I don't want anything on it to go bad any time soon, especially with only 47,000 miles on it. It gets maintained on a regular basis, with oil changes and grease jobs twice a year, and I check the fluid levels every week, topping off as necessary. The truck has been running great so far, and I want to keep it that way. Any comments/advice on how often to run it, and about modern 10%-ethanol gasoline are welcome.


  • There was talk of allowing 15% ethanol on gasoline. Except for "flex fuel" vehicles which can run up to 85%, it has not been approved yet. I wouldn't worry about running your truck any more than you are now. I have run 10% ethanol in my vehicles for at least 20 years now and have never had a fuel related problem.
  • My understanding is that 15% will now be allowed, but from separate pumps, because it's only approved for vehicles 2001 and newer. More of a bad idea, in my opinion.
  • NJ has mandated E10 since the mid-2000s. I have not had any issues with a occasionally driven (~2-3k/year) 93 Caprice with 80k miles and a 2000 Blazer with 123k miles, other than a drop in mpg (~5%).

    The only E10 issues I've had are with an Echo weedwacker and a blower, the fuel lines became gummy and had to be replaced.

    Ed B.
  • Several places in my state now have "Blender pumps" which allow you to pump anywhere from 10% to 85% ethanol fuel. They are clearly marked.
  • Please think about this statement... "One of the callers to the show said that having a vehicle sit too long with 10% ethanol gas could cause seals to dry out;" The way I see it is, there is always gas in the vehicle. It does not mater if it is sitting or not. E10 gas if it were to dry out seals it will do it sitting or being used. Now we all know any gas will go bad after some time.
  • I'm with Texases on this subject. And that brings up another point: 15% has been approved by the EPA a fuel for over-the-road vehicles, but not mandated. If it's not well accepted by the public it may not become commonplace.

    It costs a lot of money to set up an additional system. In fact, your station current has two tanks, 87 and 91, and mixes them in the pump to get 89. It won;t be able to simply mix 15% with the 10% to get its mid-grade, it'll have to be a whole seperate system. I don;t see stations making that investment unless 15% is made mandatory, and I don;t see that happening because of the "2001 or newer" constraint.
  • edited April 2012
    You might have problems with ethanol in the tank if you drove it only 3-4 times a year.
    I think you could cut the "Sea Foam" down to once a year.
    That's what I do with Chevron-Techron, and only because I buy the cheapest gas I can find.
  • edited April 2012
    There was news in my area about a month ago that Marathon gas stations had received gasoline with a higher ratio of ethanol than normal. They never said how much more but Marathon posted several advertisements on radio, TV and newspapers with warnings that the fuel could damage small engines. They were instructing customers to return the fuel and not use it in lawnmowers, weedeaters and the like. I don't use Marathon gas but have heard of several people who had "water in the gas" type symptoms when using Marathon gas in their vehicles. Speedway gas was also affected.
  • I'd like to thank everyone who has responded, you all have been helpful. What I glean from this is that I probably have nothing major to worry about? Sounds great to me. Again, thanks to all, and I'll check back again for anyone else who wants to add their "two cents worth" as well. I enjoy checking out other peoples' input.
  • edited April 2012
    I agree that with a frequently used vehicles and just like biodiesel used in cars designed for them, it's not a problem. But, let the car sit, you have potential for long term affects from water separation and all it's related running problems. Add fuel stabilizer for ethanol for gas left in your car for longer then a few unused months and it should be fine. Personally, I detest it's use and feel all the unintended consequences just adds to the frustration of car ownership.
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