How long should diesel fuel settle after unloading?
3 Answers
After unloading diesel fuel, it should stabilize for 10-15 minutes before resuming refueling operations. Refueling precautions are: Use automotive gasoline; inappropriate fuel entering the fuel system may damage the fuel system and engine. Do not use gasoline containing methanol or alcohol; avoid spilling fuel on painted surfaces to prevent damage; if the fuel tank door is frozen and cannot be opened, gently push or tap the door to remove ice and open it; prevent excessive fuel pressure from causing spraying. Solution for diesel fuel overflow from the tank: Spread fire sand over the spill and sweep back and forth to absorb the fuel. Then, place the oil-soaked sand on a sun-exposed concrete area to dry.
I've been driving heavy trucks for over a decade, and every time after refueling with diesel, I let it settle. The settling time depends on weather temperature and tank size. In summer when temperatures are high and diesel flows better, settling for 24 hours is usually sufficient; in winter, it needs at least 48 hours. For larger tanks, like those 10,000-liter ones, the settling time needs to be extended further. I usually unload the fuel in the afternoon and don't use it until the evening of the next day. Even in urgent cases, it must settle for at least 12 hours, otherwise, the water and impurities in the fuel won't settle completely, which can clog the injectors. During the settling period, never shake the tank, or the impurities will float up again, making the settling pointless.
Previously working in an oil company conducting fuel quality testing, we had to monitor sedimentation during every oil unloading process. Diesel contains water and solid particulate impurities, with higher-density contaminants slowly settling. In practice, our observation of sedimentation curves showed that 80% of impurities would settle within the first 24 hours, but to meet usable cleanliness standards, we typically recommended 24-48 hours. Special attention must be paid to temperature effects – sedimentation slows significantly below 15°C. Storage tanks with transparent viewing windows allow observation of stratification; the upper oil layer gradually becoming clear indicates completed sedimentation. Maintaining a well-ventilated and dry storage environment is also crucial.
