Can I put E85 in my flex fuel car?
Yes—if your vehicle is a true flex-fuel vehicle (FFV) designed to run on blends up to 85% ethanol. If your car is not FFV, do not use E85. This article explains how to tell if you can use E85, what to consider, and how to refuel safely.
Understanding E85 and flex-fuel technology
E85 is a gasoline-ethanol blend containing up to 85% ethanol. Ethanol has a higher octane rating and can support higher compression engines, but it carries less energy per gallon than gasoline. FFVs are equipped with sensors, fuel system components, and engine calibration that allow them to adjust the air-fuel mix automatically as ethanol content varies from 0% to 85%. Because of this design, FFVs can run on gasoline, E85, or any blend in between, depending on availability and cost.
What changes when you use E85
Because ethanol has about 70-85% of the energy content of gasoline, fuel economy typically drops when running on E85. Expect lower miles per gallon, though the cost-per-mile can improve if ethanol is cheaper in your area. Ethanol also has a higher octane rating, which can affect performance positively in some engines but may not be noticeable in others. All FFVs are designed to handle the ethanol content safely as part of their normal operation.
Is your car eligible for E85?
To determine whether you can legally and safely fuel with E85, start with the basics: confirm your car is a flex-fuel vehicle and verify the approved ethanol content from official documentation. The following checklist helps you confirm compatibility:
- Check for a "Flex Fuel" or "FFV" badge on the vehicle, often near the fuel filler or on the rear/trunk area.
- Inspect the fuel-filler door sticker or the owner's manual for language such as "E85," "up to 85% ethanol," or "FFV."
- Provide your vehicle identification number (VIN) to a dealer or manufacturer to verify FFV status.
- When in doubt, ask a service advisor or dealer to confirm compatibility.
If your car is not FFV or not labeled for E85, avoid using E85 and stick to the recommended fuel. Using E85 in a non-FFV can cause starting issues, rough operation, and potential warranty concerns.
Practical considerations when using E85
If you confirm your vehicle can use E85, consider the following factors to assess whether switching to E85 makes sense for you:
- Fuel economy: Expect a typical mpg reduction with E85 due to its lower energy content; the exact impact depends on engine calibration and driving conditions.
- Price and availability: E85 stations are not equally distributed; regional and seasonal availability can vary, affecting cost-effectiveness.
- Climate considerations: In colder weather, ethanol blends can behave differently, sometimes affecting starting/driveability; some FFVs adjust automatically, but you may notice modest differences in performance or efficiency.
- Performance and octane: E85 offers higher octane, which can improve performance in engines designed for ethanol but may not deliver noticeable gains in all models.
- Maintenance and warranty: E85 is designed for FFVs; using E85 in a non-FFV or frequently mixing fuels outside manufacturer guidance can affect components or warranties.
In practice, use E85 when your FFV is labeled for it, when ethanol is cheaper at your local stations, and when you’re comfortable with the potential mpg trade-off. Otherwise, sticking with gasoline remains the simplest and most economical option for many drivers.
Regional availability and seasonal considerations
Availability of E85 varies by region and season. Some areas have robust E85 networks, while others have limited access. In winter months, some stations may alter ethanol content or blend strategies due to temperature and supply. Always verify the pump label shows E85 (or a compatible flex-fuel blend) before refueling.
Summary
Bottom line: If your vehicle is an FFV certified to run on E85, you can refuel with E85 and may save money if ethanol is cheaper and available. If your car is not FFV, do not use E85. Consider fuel economy, price, availability, and climate before making the switch. Regularly consult your owner's manual and local dealer for guidance.
What fuel is best for flex fuel vehicles?
Flex fuel vehicles can use E85 or regular unleaded; traditional gas engines cannot use E85 flex fuel. E85 costs around 60 cents less per gallon than regular gas, but vehicles using it travel fewer miles per gallon.
Will E85 corrode flex fuel?
In fact, ethanol actually cleans fuel injectors. Ethanol doesn't corrode aluminum. It doesn't corrode anything unless the fuel is water logged.
Can flex fuel vehicles use E85?
Flex fuel vehicles, also known as FFVs, can use any fuel ranging from 0 percent ethanol to 85 percent ethanol (E85).
Can I mix E85 with regular gas flex fuel?
Yes, you can mix E85 and regular gasoline in a flex-fuel vehicle (FFV) because its sensors will automatically detect the fuel blend and adjust the engine's performance accordingly. A FFV is designed to run on any combination of gasoline and ethanol, from pure gasoline (E0) to a full E85 blend.
- How it works: The vehicle's computer senses the percentage of ethanol in the fuel tank and makes the necessary adjustments to the engine's fuel injection and timing for optimal performance.
- Before mixing: It's wise to check your owner's manual to be certain your vehicle is a flex-fuel model. Look for a yellow gas cap, an "E85" or "Flex Fuel" label near the fuel door, or markings on the car itself.
- Expected changes: Running on a fuel with more ethanol (like E85) may result in lower fuel mileage compared to regular gasoline, as ethanol contains less energy.
- What to avoid: Do not mix E85 with regular gas in a non-flex-fuel vehicle, as it can cause damage to the fuel system and engine components.
