Is EcoBoost flex fuel?

Not all EcoBoost engines are flex-fuel capable; some models are FFV, but you must verify your specific vehicle to be sure.

What EcoBoost means

EcoBoost is Ford’s family of turbocharged, direct-injection gasoline engines designed to deliver higher power with better fuel efficiency. Since its debut in 2009, EcoBoost has expanded to multiple displacements across cars, trucks, and SUVs, including small four-cylinders and larger V6 variants.

What flex fuel means

Flex-fuel vehicles (FFVs) are designed to run on gasoline blends containing ethanol from 0% up to 85% (E85). The engine, fuel system, and calibration are optimized to handle varying ethanol content. Whether a given EcoBoost engine is FFV depends on the specific model, trim, and production year.

Are EcoBoost engines flex-fuel capable?

Some EcoBoost engines are offered in FFV configurations, which allow operation on E85, but many are gasoline-only. To know for sure, check the vehicle’s labeling and official documentation for the exact build.

How to verify for your vehicle

To determine whether your EcoBoost-equipped vehicle is FFV, check these reliable sources:

• Fuel-filler door label: Look for “Flex Fuel” or “E85 capable” near the inlet.


• Window sticker (Monroney label): It will indicate “Flex Fuel Vehicle” or “FFV” if eligible.


• Owner’s manual or official specification sheet: It will specify FFV capability for the engine/trim.


• VIN-based confirmation from a dealer or Ford’s official resources: Provide the VIN to confirm FFV status.

If these sources indicate FFV, your EcoBoost is capable of running E85 or other ethanol blends. If not, treat it as gasoline-only to avoid misfueling.

Using E85 in a Ford EcoBoost FFV (considerations)

If your vehicle is FFV and you plan to use E85, consider these practical points:

• Fuel economy and power: E85 typically contains less energy per gallon, often reducing mpg by roughly 15–30% depending on the engine and driving conditions.


• Starting and cold weather: Ethanol blends can affect starting in cold temperatures; FFV calibrations address this, but you may notice differences in performance in cold weather.


• Fuel system and materials: FFV designs use ethanol-compatible components; using non-FFV gasoline is generally safe, but using E85 in a non-FFV engine can cause damage.


• Availability and cost: E85 availability varies by region and season; price competitiveness depends on local blends and taxes.


• Warranty and maintenance: Using E85 within FFV guidelines is typically supported; follow the owner’s manual for fuel recommendations.

In practice, if you have an FFV EcoBoost and plan to operate on E85, ensure you fill only with ethanol content within the vehicle’s specification and monitor any changes in fuel economy.

Summary

EcoBoost refers to Ford’s turbocharged engines, and while some EcoBoost variants are flex-fuel capable (FFV), others are not. To determine if your specific vehicle can use E85, check the fuel-labeling on the filler, the window sticker, the owner's manual, or consult a Ford dealer. If your EcoBoost is FFV, you can use E85, but expect mpg to be lower and confirm regional availability and warranty guidance. Always fuel according to the vehicle’s official specifications.

Is flex-fuel EcoBoost?

No, EcoBoost and flex fuel are not the same thing. EcoBoost is a Ford term for its turbocharged, direct-injection engines, while "flex fuel" means a vehicle can run on gasoline, ethanol, or a blend (like E85). However, some specific EcoBoost engines are offered with a flex-fuel capability (often through an available option or tune), which allows them to run on E85 in addition to regular gasoline. 
EcoBoost

• What it is: Ford's brand name for smaller-displacement engines with turbochargers and direct injection. 
• Purpose: To provide the power of a larger engine with better fuel economy. 
• Examples: Commonly found in models like the F-150 and Bronco. 

Flex Fuel

• What it is: A vehicle equipped to handle fuel blends with varying percentages of ethanol. 
• Purpose: To provide flexibility in fuel choice, often resulting in lower emissions and potentially lower cost. 
• Examples: The ability to run on gasoline, E10, E15, or E85. 

Can they be combined?

• Factory-built: Yes, some EcoBoost engines are built from the factory with flex-fuel capability, such as some 2017+ F-150 models. 
• Aftermarket: Yes, it is possible to convert a standard EcoBoost engine to run on E85 through aftermarket "flex fuel tunes," but this often requires additional modifications and can impact engine reliability if not done correctly. 

What Ford engines are flex-fuel?

The following Ford models are available as Flex Fuel Vehicles (FFVs) and can run on ethanol blends like E85:

• Ford F-150 pickup trucks (select models and trims)
• Ford Explorer SUVs.
• Ford E-Series Vans.
• F-Series SuperDuty Trucks (various models)
• F-650 and F-750 Series Trucks.
• Ford Transit Cargo Vans.

What year to avoid Ford 3.5 EcoBoost?

Years to avoid for the 3.5L EcoBoost are primarily 2011-2017, with the 2018-2020 models also having significant risks like cam phaser and 10-speed transmission issues. These earlier models can have problems including turbo and vacuum pump leaks, exhaust manifold issues, timing chain problems, and oil pan leaks, especially if the oil pan is a two-piece plastic version, common in 2017-2018 models. 
Years to be cautious about

• 2011–2012: Prone to intercooler condensation and related misfires. 
• 2013–2015: Can have issues with leaking PCV valve adapters, leading to blue or white smoke. 
• 2015: Turbocharger and timing chain problems have been reported. 
• 2017: The first year of the second-generation engine saw plastic two-piece oil pans that were prone to leaking. 
• 2018–2020: These years often had the 10-speed transmission, which could have poor shifting issues, and the cam phaser problems were still present unless they had been replaced with the updated parts. 

Years with issues to watch out for

• 2017–2018: These years used a two-piece plastic oil pan that is prone to leaking and can have backordered gaskets. 
• 2018–2020: These years often had the 10-speed transmission, which could have poor shifting issues, and the cam phaser problems were still present unless they had been replaced with the updated parts. 

Potential problems across several years 

• Cam phasers: The cam phaser issue was a known problem in many earlier models and the 2018-2020 years unless replaced with the updated parts. 
• Exhaust manifold: In the first-generation 3.5L EcoBoost (2011–2016), the exhaust manifolds can warp and break studs. 
• Oil leaks: Various oil leaks can occur, from the vacuum pump to the oil pan gasket. 
• Timing chains: Timing chain issues have been reported on various models, especially in the first-generation 3.5L EcoBoost (2011–2016). 

What type of fuel does the EcoBoost engine use?

EcoBoost engines are designed to run on regular unleaded gasoline with an octane rating of 87, but they perform best on premium unleaded gasoline with a higher octane rating (91 or higher). While using 87 octane won't damage the engine, it will result in reduced performance, such as a decrease in horsepower and torque. For optimal power, towing, and performance, especially in hot weather, premium fuel is recommended. 
Fuel types for EcoBoost engines

• Minimum requirement: Regular unleaded gasoline with a minimum octane rating of 87 (R+M)/2 is the minimum requirement. The engine will automatically adjust to prevent damage, but with a performance penalty. 
• Recommended fuel: Premium unleaded gasoline with an octane rating of 91 or higher is recommended for the best overall vehicle and engine performance. 
• Performance benefits: Using premium fuel (like 91 octane) is most noticeable when towing or in hot weather and can result in more power and better performance compared to 87 octane. Some Ford manuals mention that 93 octane can provide even better performance. 
• Ethanol blends: EcoBoost engines can use gasoline with up to 10% ethanol (E5 and E10). 

Why octane matters

• Engine knock: The engine's computer monitors the fuel quality and will reduce performance if it detects lower-octane fuel to prevent engine knocking (pre-ignition). 
• Automatic adjustment: The engine's computer is designed to automatically adjust to the fuel it is receiving, so it won't be permanently damaged by using 87 octane. It will simply "detune" to a less powerful setting to avoid damage. 
• Consistency: For consistent performance, it is best to stick with one fuel type, whether it is 87 octane for daily driving or a higher octane premium for maximum performance.