Should I Use Fuel Stabilizer in Winter?

A fuel stabilizer is an effective tool to prevent gasoline from breaking down or freezing.

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Gasoline is a mixture of petrochemicals and hydrocarbons, not engineered for long-term storage. Depending on the fuel type, gasoline can generally last up to six months before it begins to break down, mainly due to oxygenation that separates lighter, more volatile chemicals from heavier solvents. This process accelerates in the presence of water (typically with moisture condensed or accumulated inside the fuel system) or ethanol (which absorbs water easily). Ethanol-containing fuel is usually only good for up to three months of storage before it begins to degrade.

Fortunately, off-the-shelf fuel stabilizer is available as a solution to help prevent gas from going bad. Here's a look at how stabilizer works and when you might want to use it to keep your gas fresh.

What is fuel stabilizer?

Fuel stabilizer is an antioxidant that prevents fuel from breaking down into a mix of water and solvents. It also helps keep any ethanol from absorbing additional moisture and separating from the fuel. This action keeps water from corroding internal fuel system components or reaching the engine once it's started after long-term storage, where it can do severe damage. Stabilizer can also prevent the formation of varnish that can block fuel pumps and lines.

Long-term winter storage

Many enthusiasts park their vehicles for the cold winter months to prevent them from being exposed to snow, ice, and road salt. Depending on the climate, this can mean a storage period of between three and six months, long enough for ethanol-blended and non-ethanol fuel to begin breaking down.

Adding fuel stabilizer before storage can effectively prevent gasoline from degrading over the winter months. This claim is especially valid for stabilizer in ethanol-free gasoline.

Daily winter driving

Fuel stabilizer can also be helpful even for those forced to drive their vehicles through frigid climates. Some fuel stabilizers—specifically, those that work through the encapsulation of free water in gasoline—are effective as fuel line antifreeze. Once added to a tank of gas, this stabilizer lowers the freezing point of any water or moisture in the line. After encapsulating, the stabilizer allows the water to be burned inside a flammable chemical shell by the motor. This process is much easier on an engine and fuel system, and reduces the chance of ice forming in the fuel lines.

There are also specific gas-line antifreeze products that perform the same task by absorbing the water into a methanol solution, and then burning it once it reaches the engine. Methanol-based stabilizers aren't intended for long-term storage, but are quite effective at "drying out" a fuel system during cold winter weather.

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Benjamin Hunting
Benjamin Hunting is a writer and podcast host who contributes to a number of newspapers, automotive magazines, and online publications. More than a decade into his career, he enjoys keeping the shiny side up during track days and always has one too many classic vehicle projects partially disassembled in his garage at any given time. Remember, if it's not leaking, it's probably empty.