E85 is a motor fuel blend that contains between 51 and 83 percent ethanol, depending on the season and geographic location, with the remainder being gasoline. Because ethanol has a lower energy density but a higher octane rating than pure gasoline, vehicles must be specifically designed as flex-fuel to handle the corrosive nature of the alcohol and adjust the fuel injection timing.
Heard on the job
The customer filled their standard sedan with E85 by mistake and now the check engine light is on for a lean condition.
Insider tip
Winter blends of E85 often contain closer to 50 percent ethanol to ensure engines can start reliably in cold weather.
Also heard as
- flex fuel