GMC Sierra Owners Manual
Fuel E85 (85% Ethanol)
Vehicles that have a FlexFuel badge and a yellow fuel cap can use either unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85).
For all other vehicles, use only the unleaded gasoline described under Recommended Fuel on page 9‑74.
We encourage the use of E85 in vehicles that are designed to use it.
The ethanol in E85 is a “renewable” fuel, meaning it is made from renewable sources such as corn and other crops.
Many service stations will not have an 85% ethanol fuel (E85) pump available. The U.S. Department of Energy has an alternative fuels website (www.afdc.energy.gov/afdc/ locator/stations/) that can help you find E85 fuel. Those stations that do have E85 should have a label indicating ethanol content. Do not use the fuel if the ethanol content is greater than 85%.
At a minimum, E85 should meet ASTM Specification D 5798 or CGSB Specification 3.512. Filling the tank with fuel mixtures that do not meet ASTM or CGSB specifications can affect driveability and could cause the malfunction indicator lamp to come on. As the outside temperature approaches freezing, ethanol fuel distributors should supply winter grade ethanol, the same as with unleaded gasoline. Winter grade blends typically do not exceed 70% ethanol (E70).
The starting characteristics of ethanol make it more difficult to start below 0°C (32°F), which may lead to longer start/crank times. Engine start on ethanol fuels down to −30°C (−20°F) is possible, provided a winter grade ethanol blend is used.
It is best not to alternate repeatedly between gasoline and E85. If you do switch fuels, it is recommended that you add as much fuel as possible — do not add less than 11 L (3 gal) when refueling. You should drive the vehicle immediately after refueling for at least 11 km (7 mi) to allow the vehicle to adapt to the change in ethanol concentration.
E85 has less energy per liter (gallon) than gasoline, so you will need to refill the fuel tank more often when using E85 than when you are using gasoline. See Filling the Tank on page 9‑77.
Notice: Some additives are not compatible with E85 fuel and can harm the vehicle's fuel system.
Do not add anything to E85.
Damage caused by additives would not be covered by the vehicle warranty.
Notice: This vehicle was not designed for fuel that contains methanol. Do not use fuel containing methanol. It can corrode metal parts in the fuel system and also damage plastic and rubber parts. That damage would not be covered under the vehicle warranty.