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AAA: Not All Gasoline Created Equal

Tests Show Quality Gasoline Keeps Engines 19 Times Cleaner

BELLEVUE, Wash. — New testing from AAA has uncovered significant differences in the quality of gasoline sold at fuel retailers in the United States. The independent laboratory testing compared gasolines that meet TOP TIER™ standards often marketed to consumers as having enhanced, engine-cleaning detergent additives with gasoline brands that do not participate in the automaker-backed program. Among brands tested, non-TOP TIER™ gasolines caused 19 times more engine deposits than TOP TIER™ brands after just 4,000 miles of simulated driving. Such carbon deposits are known to reduce fuel economy, increase emissions and negatively impact vehicle performance, particularly on newer vehicles. To protect vehicle investments, AAA urges drivers to use a gasoline that meets TOP TIER™ standards for engine cleanliness and performance.

“AAA was surprised to learn the extent to which detergent additives impact gasoline quality,” revealed John Nielsen, AAA’s managing director of Automotive Engineering and Repair. “As advertised, tested TOP TIER™ gasolines kept engines remarkably cleaner than other fuels we tested.”

In response to increasing levels of carbon deposits in modern engine designs, the Environmental Protection Agency mandated a minimum level of detergent for all gasoline sold in the United States in 1996. However, some automakers believe the minimum does not go far enough to ensure optimal vehicle performance and their ability to meet increasingly-stringent fuel economy and emissions requirements. The TOP TIER program and performance standard were developed to guarantee that program participants’ gasoline meets stricter targets for engine cleanliness.

“When it comes to selecting a gasoline, automakers got it right – TOP TIER™ gasoline performs best,” continued Nielsen. “By selecting a quality gasoline, drivers can minimize engine deposits, increase vehicle performance and improve fuel economy.”

Despite the fact that two-thirds of U.S. drivers believe there is a difference in quality of gasoline sold by different gas stations, a AAA survey reveals that Americans value convenience and price over quality when it comes to selecting a gas station.

  • Three-quarters of U.S. drivers choose a gas station based on location (75 percent) or price (73 percent).
  • Nearly one-third (29 percent) of U.S drivers choose a gas station based on a rewards
    program.
  • Only 12 percent of U.S. drivers select a gas station based on whether the gasoline
    contains an enhanced detergent package.
  • Nearly half (47 percent) of U.S. drivers do not regularly buy gasoline that contains
    an enhanced detergent additive.
  • Men (44 percent) are more likely than women (26 percent) to regularly buy a gasoline
    that contains an enhanced detergent package, as are baby boomers (41 percent) compared to millennials (32 percent).

“Americans are six times more likely to choose a gas station based on the price of gasoline rather than the quality of the fuel,” continued Nielsen. “Since TOP TIER™ gasoline is widely available and only an average of three cents more per gallon, AAA urges drivers to reconsider their priorities when selecting gas station.”

To ensure a gas station sells a high quality gasoline, consumers should research the fuel options near them. According to TOP TIER™, one-third of gas stations meet the TOP TIER™ standard for fuel quality. Retailers interested in participating in the TOP TIER™ program can find additional information at TopTierGas.com.

“Fortunately, consumers can reverse some engine deposits simply by switching gasoline brands,” said Greg Brannon, AAA’s director of Automotive Engineering. “After a few thousand miles with TOP TIER™ gasoline, performance issues like rough idling or hesitation during acceleration can often be resolved.”

For testing purposes, AAA selected TOP TIER™ and non-TOP TIER™ gasolines from a southern Texas market that represents the type of gasoline sold across the majority of the United States. To measure intake valve and combustion chamber deposits, AAA engaged the services of an independent International Standards Organization 17025 certified engine testing lab to perform an American Society for Testing and Materials standard test on fuels.

To evaluate consumer gasoline preferences, AAA contracted with a national research company to perform a telephone survey of 1,002 adults (18 years of age and older) living in the continental United States. Survey results are an accurate representation of the total continental U.S. population, 18 years of age and older, with a margin of error of +/- 3.1 percent at a 95 percent confidence level.

For additional information about fuel quality, including the full test report and fact sheet, visit NewsRoom.AAA.com

About AAA Washington:

AAA Washington was established in 1904 by 10 prominent Seattleites determined to champion the betterment of motoring conditions and laws, the preservation of Washington state’s natural beauty and the promotion of Washington as an unrivaled tourist destination. Nearly 120 years later, the club continues to pursue these on behalf of its 1.2 million members. 

Members of AAA Washington receive exclusive benefits, including roadside assistance, discounts on hotels and rental cars, comprehensive insurance options, and personalized trip planning. AAA Washington was named a Best Place to Work by Puget Sound Business Journal and voted the best Travel/Tourism Company by 425 Business readers in 2023, and AAA was named one of the most trusted travel and automotive brands in the U.S. Additional information is available through the company’s Washington and northern Idaho stores and at www.AAA.com. 

About AAA Foundation for Traffic Safety:

Established in 1947 by AAA, the AAA Foundation for Traffic Safety is a nonprofit, publicly funded, 501(c)(3) charitable research and educational organization. The AAA Foundation’s mission is to prevent traffic deaths and injuries by conducting research into their causes and by educating the public about strategies to prevent crashes and reduce injuries when they do occur. This research is used to develop educational materials for drivers, pedestrians, bicyclists and other road users. Visit www.AAAFoundation.org.

Media Contact

Fearey o/b/o AAA Washington 
AAA@feareygroup.com 
206-838-9209 

Twitter: @AAA_Washington
Facebook: AAA Washington
Instagram: aaawashington

Interested in planning your next road trip with AAA Washington? Call your travel agent directly or your nearest AAA store to get pro tips, TripTik maps, and more. Find more Pacific Northwest scenic drives and road trips.

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