Does E85 gas cause engine damage

Many factors contribute to vehicle damage. From objects on the road to other road users to internal problems, the list is endless. Similarly, fuel can also cause engine damage. Generally, you expect the fuel you use is safe for your engine’s consumption.

However, with various ethanol blends available in gas stations, many drivers are concerned about what damage they may cause to their engine. Specifically, this article aims to provide insight on e85 engine damage.

What is e85?

E85 gas, or flex-fuel, is the gasoline that contains 85% ethanol and 15% regular gas. Ethanol is a renewable source of energy that originates from biomass sources such as corn, ‘starchy’ wastes, and grains.  It blends with gasoline at varying degrees to raise octane levels while reducing pollution; hence the derivatives e10, e15, and e85.

What is e85

A common additive to gasoline, many vehicles run smoothly with at least e10 blend, without experiencing any issues. However, with continued use, such mixtures may cause wear and damage to your engine. Using higher blends than recommended also contributes to severe engine damage.

E85 gas runs smoothly only on vehicles explicitly made to use it, otherwise known as Flex Fuel Vehicles (FFVs).  Using this blend in non-FFVs could lead to the engine stalling. There are several ways to find out if your vehicle is a flex fuel vehicle.

You may opt to check the label on your fuel door if it indicates it is FFV by checking your owner’s manual or websites like, where you can establish whether your car is a flex-fuel vehicle with your vehicle’s VIN or the U.S. Department of Energy’s Alternative Fuels Data Center.

What happens if you put e85 in your car by mistake?

Flex-fuel vehicles can easily switch between e85 gas and regular gas, without any engine complications. However, if you fill up your non-FFV with e85 gas, some issues are bound to occur, if there is no immediate action. You can quickly fix it by filling up the rest of your tank with regular gas and riding it out.

Misfueling a vehicle with e85 for the first time should not cause any long-term damage. However, if you have filled up

your tank with the fuel, you will have to pump it out completely and replace it.

Flex-fuel vehicles

Is e85 bad for your engine?

The lower price of e85 gas may lure many drivers into using it; however, they have to be careful, since flex fuel is only useful in FFVs. Some problems e85 gas may cause your vehicle include:

Fuel components degradation

Non-FFVs do not have the proper fuel system components to handle ethanol burning in their engines. As a result, their fuel systems may deteriorate due to ethanol’s corrosive nature. Repairing and replacing your vehicle’s fuel intake components may cost you even more than your car’s overall value. You may also opt to tune up your non-FFV to enable it to use e85 gas, which is also an expensive option.

Damages seals and gaskets

Older vehicle models consist of rubber and plastic parts, which ethanol can easily destroy. Similarly, regardless of modern vehicles having ethanol-compatible fuel systems, storing ethanol for a long time may lead to the growth of acidic bacteria in the alcohol mixture, accelerating damage to the delicate gaskets and seals.

For car owners storing vehicles with ethanol fuel in the tank, it is advisable to add fuel stabilizer designed explicitly for the ethanol blend in your tank, to prevent acidification of and bacteria growth in the fuel.

e85 gas

Severe engine failure and damage

Ethanol absorbs water, especially in cold weather, and breaks down much faster than gasoline. In small engines, or if you have little fuel in your gas tank, the ethanol absorbs water, and water in your tank causes the vehicle to stall. Water in the fuel also leads to the formation of rust in the interior surfaces of your engine, leading to a clogged fuel filter and damage to your pistons, seals, and rings, among many other engine components.

Ethanol blends also decrease the life span of engines and their components. Whether it is through the formation of rust or quick deterioration of engine components, such fuel makes non-FFV engines age faster. Ethanol is also highly susceptible to pre-ignition, thus, causing poor fuel economy, ‘pinging’ or ‘spark’ sounds in your engine, slow acceleration, and backfiring, among many other mechanical issues.


When used in the right vehicles, e85 gas has its advantages. For instance, it is from renewable sources, unlike regular gasoline, which is from fossil fuels, which are increasingly becoming depleted from the earth’s surface.

Ethanol is also much cleaner than gasoline. As a result, it has fewer toxic gas emissions, meaning a decrease in the rate of environmental pollution.

The consequences of e85 engine damage are lethal and costly to repair. Always use the proper fuel in your vehicle. Check your owner’s manual and follow the fuel specifications and guidelines, if you want to change the type of fuel your vehicle uses. There are also ethanol additives that you can use in your car to prevent ethanol-related issues.

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