Here you go, and though the article pertains to ethanol fuels, there is one part that is pertinent to this thread. I've put it in bold.
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Gas/Ethanol Fuels: Tank Up!
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by Bob Hoffmann, from the March 2001 Newsletter
It irked me immediately when I saw it. Perhaps you’ve seen it as well: The sign in front of a local Chevron station that read "Prevent expensive engine repairs; buy ethanol-free fuels here." When I lived in Ohio, I usually filled my gas tank with 10% ethanol blends, and had never had a problem with them. I also liked the fact that my fuel dollars helped feed the farmers who grew the corn from which ethanol was distilled. Gasoline mixed with ethanol produces less carbon monoxide and smog compared to straight gas. Finally, since ethanol is produced domestically, and much of our petroleum supply comes from abroad, I was buying locally, so to speak, reducing the trade deficit, and keeping oil rigs out of environmentally sensitive areas. So when I saw the ethanol-disparaging sign, I stopped my petroleum-consuming means of conveyance at the nearest parking spot and walked in to see Marc, the station owner. Yes, he was responsible for the sign. Yes, he claimed, ethanol-blended fuels could damage vehicle engines.
He launched into a litany of ethanol-related problems. Ethanol oxidizes metal parts, which can result in the clogging of fuel injectors. Additionally, ethanol has a tremendous ability to attract and absorb water. This causes performance and mechanical problems. He mentioned a number of other supposed problems caused by ethanol.
I was skeptical, but he seemed to be presenting his case in a very scientific manner. "If you claim ethanol is so damaging," I asked, "Why do all automakers allow its use under warranty?" Simple, he responded; because the Environmental Protection Agency requires the use of ethanol in certain markets, therefore the automakers have to cover it in their warranties. Indeed, ethanol-blended gas obviously damages engines, because "I get service bulletins on this all the time."
To see if he was having a common misunderstanding in the automotive world, I asked if he wasn’t confusing ethanol with methanol, a much more toxic and corrosive fuel additive. "They’re both alcohols, aren’t they?" he responded. I was shocked that a mechanic would be equating the two.
"If you had a glass of ethanol and a glass of methanol, would you drink both?" I asked.
"I never drink," he responded flatly. Probably a good thing, I thought, since he doesn’t know the difference. I finally asked him if he had any proof of his claims. Where were those service bulletins he was constantly receiving? He didn’t have any on hand, but if I’d come back later, he’d show me what he could find.
When I returned, he had printed two chapters of Motor Gasolines Technical Review, a publication available on the Chevron Web site (
http://www.chevron.com/prodserv/bulletin/motorgas/). He had highlighted the presumably pertinent passages. "What about service bulletins?" I asked. He didn’t have any for me, but suggested that I contact the individual automakers.
So what did the Chevron document contain to support his claims that ethanol blends could damage engines? In a word, nothing. Motor Gasolines Technical Review’s chapters on engine systems, including fuel injectors, did not mention ethanol a single time. The document did mention methanol's "corrosivity and toxicity defects," leading me to believe that this was another case of confusion between ethanol and a similar-sounding, but very different alcohol. After contacting customer service at Ford and Chrysler, and contacting local GM and Jeep/Nissan dealers, I couldn’t find any service bulletins or other documents claiming that ethanol damages the engines or components of any vehicles. Typically, service staff remembered hearing of this supposed damage in the past. Some said that ethanol actually had caused corrosion and deposits on the fuel injectors of early- to mid-1980's cars. Others said, no, not corrosion, but erosion. The details varied, but one thing was constant: The inability to produce supporting documentation.
I then contacted the American Coalition for Ethanol (
http://www.ethanol.org/) and spoke with Trevor Guthmiller. He said that ethanol, besides being an alcohol, could be characterized as a detergent. It can loosen carbon deposits, particularly in older vehicles, but since many fuels now contain detergents, this effect is not unique to ethanol. He was very firm that this would not damage engines. "The fuel filter will capture any loose carbon deposits, so if you switch from leaded gasoline to a detergent fuel, you will eventually have to change your fuel filter." He also stated that he’d never seen any documentation about ethanol damaging fuel injectors. "Automakers were cautionary about ethanol fuel blends in the beginning, but after thorough testing, they realized that it wasn’t ethanol that was causing problems," he told me. "Methanol blends were frequently responsible for engine damage." Since then, automakers have endorse, without reservation, the use of gasoline blended with up to 10% ethanol. This is born out by Ford Motor Company’s Technical Article: Ethanol/Methanol Fuel Blends:
Ford Motor Company vehicles should operate normally if the customer uses blends that contain no more than 10% ethanol or a blend that contains no more than 5% methanol with its necessary co-solvents and additives. If the methanol does not contain the necessary co-solvents & additives, it will damage the vehicle.
Note that Ford’s statement is without qualification in terms of vehicle model, production year, or the presence of fuel injectors. Also note that a 10% blend is the maximum typically available, so if you buy an ethanol-blended fuel, you don’t have to worry about whether the ethanol concentration is too rich for your vehicle.
What about the claim that automakers allow the use of ethanol blends only because the E.P.A. mandates ethanol blending in certain areas? There is no such requirement. According to the Clean Air Act Amendments of 1990, "All gasoline sold in the specified carbon monoxide nonattainment areas during the winter months when the carbon monoxide level is the highest must be oxygenated gasoline with a minimum oxygen content of 2.7 weight percent." There is no requirement for the use of ethanol, ever. The requirement is simply to use an oxygenated additive, and ethanol is one of several currently available. Chevron itself uses ethanol to oxygenate gasoline in numerous markets, such as Seattle, Spokane, Vancouver, and Portland, while it uses another common oxygenate, MTBE, in other areas. Incidentally, MTBE is the same additive that the EPA would like banned in motor fuels, as it is contaminating ground water supplies.
What about ethanol’s water-absorbing capabilities? Yes, water is soluble in ethanol, otherwise you would have to shake your beer to mix the alcohol with the water, and we know what a mess that would make. In terms of fossil fuels, Chevron states that a gasoline-alcohol blend can dissolve water up to 6000-7000 ppm at 70°F. "When this blend is cooled, both the water and some of the ethanol become insoluble. The result, in both cases, is two layers of liquid: an upper ethanol-deficient gasoline layer and a lower ethanol-rich (about 75% ethanol) water layer. The engine will not run on the water layer." (Chapter 4, Motor Gasolines Technical Review)
Chevron did not state the likelihood of this degree of contamination. But they specifically state that ethanol is transported in such a manner as to prevent contamination with water. While a 10% ethanol-gas blend can dissolve up to 40 times more water than straight gasoline, Trevor Guthmiller of the American Coalition for Ethanol states that it is highly unlikely that gasoline will come into contact with enough water to result in such high concentrations. This amount of water in your gas tank can stop your car dead, whether or not the gasoline is blended with ethanol. Because ethanol-blended gasoline can dissolve water, it greatly reduces the chance of fuel-line freeze-up or water accumulation in your gas tank (e.g. due to condensation). Any water is diluted throughout the fuel and passes through the fuel line and combustion system with little or no compromise in performance. This effect, says Guthmiller, is responsible for ethanol blends gaining market share in the winter in South Dakota, where he is based.
There are a number of other supposedly negative claims against the use of ethanol in fuel. These claims tend to vaporize with careful research. So you can confidently fill your gas tank with ethanol blends. They burn cleaner, support American farmers, and reduce the dependence on imported fossil fuels.
Chevron Corporation was asked to comment on technical issues and any policy about anti-ethanol signage at Chevron service stations. They forwarded the inquiry to the consumer affairs department three weeks before the press deadline, but no response has been forthcoming.
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Bob Hoffmann is the Web Master of the Moscow Food Co-op. He prefers to get around town by bike or foot, although you can occasionally see him changing the climate in his Jeep Cherokee. He will happily reconsider his endorsement of ethanol when presented with credible scientific evidence.
