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Rust in the Fuel System? Ethanol May Be the Culprit
Your response to Glenn Fitzpatrick ("4xForum," Feb. '12) regarding rust in the fuel system of his Jeep should have included a warning regarding the use of gasoline containing ethanol. Ethanol is pretty nasty stuff to many materials (especially steels and rubbers) and was traditionally used in fuel systems before its introduction to the U.S. gasoline infrastructure in the 1970s. When automotive testing first began using ethanol blends, rusting of steel components, corrosion on other metallic components (carburetor, fuel pumps, and fuel bowls), and swelling and distortion of rubber components was seen. Automotive manufacturers responded by upgrading fuel system materials where possible to minimize these problems.
Due to its proclivity to absorb water, ethanol is particularly nasty to traditional steel used in fuel tanks, fuel lines, and injector rails, causing rapid rusting on wetted internal surfaces. Witness the trending switch to plastic fuel tanks and stainless-steel fuel system components by most automotive manufacturers since the late '70s, when ethanol first began being blended with gasoline in the commercial market. You only have to look at the motorcycle, snowmobile, and lawn and garden equipment markets during the recent past where warranties were voided if fuel containing ethanol was used in their products to see the negative effects of ethanol usage unless upgraded fuel system materials are used.
Ethanol has half the energy content of gasoline. In a closed-loop engine system that uses an oxygen sensor to control the fuel delivery, this presents no problem other than the loss of fuel economy (5 percent with the use of 10 percent ethanol blend). In an open-loop system, the use of ethanol results in a lean fuel mixture (again, 5 percent with the use of 10 percent ethanol blend). This is particularly bad for a two-stroke engine, where overheating and piston seizure may occur.
Here in Michigan, ethanol can usually be avoided by the purchase of premium grade fuel. I use premium in my Jeep, my Harley, my snowmobiles, and my yard equipment. There are commercially available kits for testing the presence of ethanol in gasoline. If you prefer to use regular grade fuel, the occasional use of these kits is much more economical than the disassembly and repair of the fuel system or the replacement of a failed two-stroke engine.
Phil Toney, Retired Jeep engineer
Phil, thanks for your very informative email. Most states in the U.S. have sold gasoline labeled as including "up to 10 percent ethanol" since the Energy Independence & Security Act of 2007 required that fuel producers increase their use of renewable fuels every year through 2020. Here we are in 2013 and 15 percent Ethanol (E15) blend fuel is now being pushed down our throats. The American Automobile Association and other auto-friendly organizations have requested the sale of E15 be suspended, and it has been reported that many auto manufacturers will not honor warranties on autos running E15, despite the fact that the all-knowing EPA has certified it to be safe in all 2001-and-newer vehicles. Thank for writing, Phil. You are a wealth of knowledge. We always love hearing from you! 'Wheel on, Sir.