Can you use regular gas in a flex-fuel vehicle?

By Product Expert | Posted in FAQs, Technology, Tips and Tricks on Thursday, January 30th, 2020 at 8:35 pm
A sunrise over the planet earth as seen from space.

Flex-fuel vehicles, or FFVs, are optimized to be able to run on special ethanol- and methanol-based fuels. But what happens if you put regular gasoline in the tank? Can regular gas be used in a flex-fuel vehice?

View Our Pre-Owned Flex-Fuel Vehicle Inventory

Yes, standard gasoline can be used in flex-fuel vehicles. The engine inside FFVs is designed to run on gasoline as well as other fuels. This generally means gas blended with ethanol and methanol. No matter what fuel you put into your FFV, it’s stored in the same tank.

A hand holds a fuel pump in the gas tank of their car.

What fuels should not be used in an FFV?

Do not put diesel or regular leaded gasoline inside an FFV. Admittedly, leaded gasoline is very rare these days, but if you happen to come across some, keep it out of your FFV tank. The flex-fuel designation generally means you can put E85 gasoline or regular unleaded gas in your vehicle.

Does using regular gas in a flex fuel vehicle harm the engine?

No. Putting E85 in a vehicle not designed for it is harmful, however.

Ever Wonder: Why is there a lot of oil in the Middle East?

What does the number in flex-fuels mean?

The number after the E in a fuel like “E85” refers to the percentage of ethanol that’s mixed in. E85 fuel, for example, is composed of 85% ethanol.

How does ethanol affect fuel economy?

With most FFVs, the more ethanol that’s in the fuel, the larger the drop in your fuel economy. The reason for this is that ethanol burns faster than regular gas.

Is ethanol better for the planet?

Though originally marketed as a “green” option, it’s debated whether ethanol is actually better for the planet than fossil fuels. Ethanol typically comes from corn, so making it requires using a lot of land to grow and harvest. The corn then has to be refined into ethanol. This whole process can be taxing to mother earth. However, ethanol is theoretically a renewable fuel, whereas fossil fuels are not.