At what sub-zero temperature will No. 0 diesel freeze?
3 Answers
Theoretically, No. 0 diesel will freeze at 0°C. Here are the relevant details: 1. Diesel: The most important use of diesel is for diesel engines in vehicles and ships. Compared to gasoline, diesel has a higher energy density and lower fuel consumption rate. Due to its low energy consumption, some small cars and even high-performance vehicles have switched to diesel. 2. Freezing Point: The freezing point refers to the highest temperature at which the surface of the oil sample no longer moves under specified test conditions when cooled, expressed in °C. The freezing point and cold filter plugging point are important indicators of diesel's low-temperature performance.
Last time I was driving a diesel car in the northeast, when the temperature dropped to around -5°C in winter, the No. 0 diesel fuel started to freeze. That time, I encountered -8°C, and the entire fuel tank waxed up, making it impossible to start the engine no matter what. It was quite frustrating. Generally speaking, the design standard for No. 0 diesel fuel is that the freezing point should not be lower than 0°C, but in reality, when the ambient temperature drops to -5°C, it may start to wax and solidify, especially in northern regions. Why does it freeze? Mainly because the low temperature causes the paraffin in the diesel fuel to crystallize and precipitate, clogging the filters and fuel lines, leaving the car completely immobilized. The preventive measure is to use diesel fuel with a lower grade in winter, such as -10 or -20, which have lower freezing points and can withstand temperatures below -10°C; or add diesel anti-gel agents by pouring some into the fuel tank in advance. During sub-zero weather, I often check the weather forecast. Once the temperature is predicted to approach -5°C, I switch to a lower-grade diesel fuel to avoid the hassle of waiting for rescue and having to heat the fuel lines. Remember, -5°C is the critical point—don’t try to save a little money on this.
For those of us living in northern regions, it's common knowledge that No. 0 diesel can freeze at temperatures around -7 or -8 degrees Celsius. Like during last year's cold snap when temperatures dropped to -9°C, a friend's car couldn't start at all because the diesel had frozen, and calling a tow truck was such a hassle. The freezing point of diesel isn't absolute, but standard No. 0 diesel typically starts causing problems at around -5°C, as the cold makes the fuel thicker and less fluid. Local gas stations rarely sell No. 0 diesel in winter, mostly offering -10 or -20 grades to suit the cold weather. I recommend keeping an eye on the thermometer; if it's below -5°C, don't take the risk—switch to winter-grade fuel or add anti-freeze additives in advance. I've had good results with anti-gelling agents. Also, keeping the fuel tank insulated is crucial; don't park the car in a windy spot, or you might find it frozen overnight. Remember this critical threshold—safety first, don't cut corners to save money.
