How Long Does Gasoline Take to Deteriorate in a Car?
2 Answers
Gasoline stored in the fuel tank for less than ten days will not significantly deteriorate. However, if the car is parked for more than a month, it is recommended to drain the gasoline from the tank, clean the tank, and then start the engine. Generally, gasoline has a shelf life of three months. Types of Fuel: The deterioration rate largely depends on the type of fuel. Under the same conditions, if not stored properly and exposed to air, gasoline will inevitably deteriorate. Ethanol-blended gasoline, for instance, typically becomes unqualified within a week, while premium gasoline can last up to three months. Sealing Conditions: The sealing condition also plays a crucial role. Ethanol-blended gasoline is highly hydrophilic and sensitive to water. When it absorbs enough water vapor, it forms a milky-white layer and becomes unusable. Premium gasoline is less sensitive to water but can still oxidize, leading to reduced anti-knock properties. It also has a shelf life, though storing it for 5 to 6 months is generally not a major issue. Prolonged storage of gasoline causes oxidation, forming gum that can stick valves and prevent them from sealing properly. At high temperatures, this gum decomposes into carbon deposits that accumulate in fuel lines and other components, resulting in poor engine performance.
As an enthusiast who often helps friends deal with used cars, I have to say that gasoline shelf life is not something to be taken lightly. Regular gasoline can start to oxidize and deteriorate in the fuel tank after just 3 months, and over time, it can form gums and sediments that clog fuel lines and damage the engine. The last time I worked on an old car that had been sitting for half a year, the fuel tank had sticky, gelatinous deposits. It's even worse with ethanol-blended gasoline, which absorbs moisture and can separate and degrade within a month. So if your car is going to sit idle for a long time, I recommend not filling the tank completely—leave about a quarter of the space empty. It’s also a good idea to start the engine and drive for about 20 minutes each month to circulate the fuel. If you really need to store it long-term, consider adding a bottle of fuel stabilizer to extend its lifespan.
