Why does the fuel level drop so quickly after refueling?
2 Answers
First of all, don't rely too much on the fuel gauge as it's not very accurate. Some car owners have driven more than 80 kilometers even after the fuel light came on. If you're still concerned, you can check the fuel pump yourself, as it might be malfunctioning. Here are some precautions for refueling your car: 1. Refuel in the morning or evening: Gasoline is charged by volume rather than weight, and it expands with heat and contracts with cold. Refueling in the morning or evening when temperatures are relatively lower means the same volume of gasoline can have a higher mass, saving you money. Even with a 15-degree temperature difference between morning and evening, there's a difference of 0.62L. Even if it's not much, the risk of danger is lower at lower temperatures. 2. Don't fill the tank completely: When driving in the city, there's no need to fill the tank completely because city driving involves frequent stops and starts. A full tank increases the engine's load. It's best not to exceed two-thirds full. Overfilling can cause gasoline to overflow, which may flow into the intake manifold and "drown" the spark plugs, causing the engine to stall immediately after refueling. In severe cases, the car may not start normally, and gasoline might even leak from the carbon canister, which is very dangerous if exposed to open flames. 3. Don't wait until the tank is empty: The fuel pump in the tank relies on gasoline for cooling. If the gasoline level is too low and doesn't cover the pump, prolonged operation in this state may reduce the fuel pump's lifespan. This is less of an issue in winter but poses a higher risk in the hotter summer months. 4. Avoid refueling during thunderstorms: Try not to refuel your car during thunderstorms because the fuel nozzle may introduce stray currents into the fuel tank, increasing the movement of unstable gasoline molecules and creating potential fire or explosion hazards.
After driving for so many years, I've encountered quite a few situations where the fuel seems to deplete especially fast right after filling up, and the most common reason is driving habits. For example, when I hit the highway and stomp on the accelerator, or frequently accelerate sharply in city traffic jams, the engine works harder and fuel consumption skyrockets; sometimes, I crank the air conditioning to max for comfort, and the compressor guzzles fuel too. Low tire pressure increases rolling resistance, forcing the engine to work harder, and engine carbon buildup reduces combustion efficiency, both causing the fuel gauge to drop quickly. I make sure to maintain my car regularly, changing the oil and cleaning filters, and driving as smoothly as possible saves a lot of fuel; tracking the mileage per tank revealed that actual fuel consumption doesn’t vary much, with psychological factors playing a part—constantly checking the fuel gauge right after filling up makes it seem like it’s dropping faster.
