Journal-News

Wheels: Last week you discussed gasoline, and you advised everyone to use the octane rating recommended by the vehicle manufacturer as found in the owner's manual. Also, you stated that gasoline should not be stored for longer than 90 days (3 months).

Halderman: To clarify the use of premium in a vehicle that recommends premium gasoline. Sometimes using midgrade (plus) or even regular may not affect the performance or the fuel economy. Try it to be sure. I have tried using lower octane and found a decrease in fuel economy. However, if the owner's manual specifies premium only, then always use premium.

Wheels: This week you said that the topic would be ethanol. What is ethanol?

Halderman: Ethanol is the "good" alcohol used as an additive in gasoline. Ethanol is made from grain and is therefore often called "grain alcohol." Ethanol is the alcohol in beer, wine and spirits. When ethanol is manufactured for use as a gasoline additive, it is mixed with 2 percent to 4 percent gasoline to denature the alcohol to make it undrinkable. Alcohol absorbs moisture and can cause corrosion so it has to be transported by tanker rail cars or by truck and cannot be sent through pipelines. This makes the use of ethanol restricted to an area around ethanol plants, which are mainly in the Midwest. Ethanol is also called ethyl alcohol and when added to gasoline, it used to be referred to as "gasohol."

Wheels: Is all ethanol made from corn?

Halderman: While most ethanol is produced from corn, ethanol can be made from other organic plants such as switch grass, corn stalks, sawdust, paper sludge, rice straw and yard clippings. However, using these sources to make ethanol requires more expensive equipment and longer processing.

Wheels: You mentioned gasohol as gasoline and ethanol blended together, but that was in the 1980s. Has ethanol always been used in gasoline?

Halderman: No. Ethanol is now the additive required to be added to gasoline to help reduce carbon monoxide exhaust emissions. In the past, the U.S. Environmental Protection Agency (EPA) mandated the use of methyl-tertiary-butyl-ether (abbreviated MTBE). However, MTBE has been found to cause risk to the environment, so the EPA mandated that ethanol be used to replace MTBE.

Wheels: What is E10?

Halderman : E10 is the term used to indicate gasoline that has 10 percent ethanol added. Over 80 percent of the gasoline sold in the country has 10 percent ethanol added to reduce carbon monoxide exhaust emissions and help reduce the amount of imported oil. Next week: E85.

James D. Halderman is an ASE-certified master technician, a member of the Society of Automotive Engineers and the author of 12 textbooks. Submit your automotive care questions to Halderman via e-mail at jhalderman2@juno.com, or write him in care of: Wheels, Marketing Publications Department, Dayton Daily News, 1611 S. Main St., Dayton OH 45409.