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What kind of oil does E85 use?

In short, E85 does not rely on oil as its primary ingredient. It is a flexible-fuel blend that uses ethanol—bioethanol—as the main component, with up to 15% gasoline. The ethanol is produced from plant-based feedstocks, while the gasoline portion is sourced from conventional petroleum fuels. In the United States, E85 is typically up to 85% ethanol and 15% gasoline, though exact percentages can vary by country or region.


What E85 is and how it works


E85 is designed for flexible-fuel vehicles (FFVs) that can run on a wide range of ethanol-gasoline blends. The term “oil” is a simplification; the fuel’s main ingredient is ethanol, a renewable alcohol produced by fermenting sugars and starches.


Before outlining the key components, consider this quick primer on balance and use:



  • 85% ethanol (bioethanol) by volume at the high end

  • Up to 15% gasoline or other hydrocarbon fuel


Note that the exact mix can vary and some regions may advertise different blends. Ethanol’s higher octane can improve combustion characteristics for certain engines, but its lower energy density can affect fuel economy in non-FFV vehicles.


Where the ethanol comes from


The ethanol component is produced from renewable feedstocks. In the United States, corn is the dominant source; in Brazil, sugarcane is a major source; there is growing use of cellulosic biomass (wood, grasses, agricultural residues) for next-generation ethanol, though adoption varies by market and policy support.


Before listing the common feedstocks, here is a concise look at the usual categories:



  • Corn-based ethanol (primary in the U.S.)

  • Sugarcane-based ethanol (primary in Brazil and some other regions)

  • Cellulosic/advanced ethanol (from non-food biomass and wastes; ongoing development)


Ultimately, the blend’s composition and feedstock mix influence lifecycle emissions and economic considerations, while compatibility remains tied to FFV technology.


Vehicle compatibility and practical considerations


Not all vehicles are compatible with E85. Flexible-Fuel Vehicles (FFVs) are designed to operate on gasoline, E85, or any blend in between. Using E85 in a non-FFV can cause engine or fuel-system problems. Always check the vehicle’s label or owner’s manual for confirmation.


Before listing the practical points, consider these:



  • FFVs can use a wide range of ethanol-gasoline blends

  • E85 typically offers higher octane but lower energy content, affecting fuel economy

  • Cold-start performance, material compatibility, and sensor calibration may differ with high-ethanol blends


When used in appropriate engines, E85 can offer renewable fuel benefits and support for rural economies that produce ethanol feedstocks, with lifecycle emissions dependent on feedstock and production methods.


Summary


In essence, E85 uses ethanol as its main component and does not rely on oil as its primary ingredient. The remaining portion is gasoline, which can be derived from petroleum. The ethanol portion is sourced from renewable crops or wastes, with regional variations in feedstock and regulatory standards. Vehicle compatibility and performance depend on using the fuel in FFVs and understanding its energy content and octane benefits.

Kevin's Auto

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.