What is good to know about motor fuels in the winter months

Why are fuels split into summer and winter?

Summer and winter motor fuels have the optimum quality for the climatic conditions of the respective season. They are also tailored to the environmental aspects that affect fuel handling - for example, petrol vapor pressure in the summer.

How do the composition and properties of summer and winter fuels differ?

The difference between summer and winter fuel is given by the season in which it is used. During the summer, motor fuels are not exposed to low temperatures, which are sensitive to both petrol and diesel fuel.

The actual composition of diesel fuel is slightly different in the winter to ensure better fuel resistance to low temperatures. Diesel fuel contains fewer heavy paraffins, which tend to crystallise first at temperatures below zero. Diesel fuel also contains special additives in the winter to help eliminate the negative behavior of paraffins, which are a natural part of fuel. The function of additives is to inhibit the formation of paraffin crystals while preventing clumping.

In winter, besides diesel engines, different requirements apply to spark the ignition of engines. The main difference from summer fuel is that it contains more volatile ingredients. Thanks to the volatile components, it has to be fuel-vapor-proof, which in combination with the distillation profile ensuring reliable a start-up and smooth running of the engine even at low temperatures.

When do the service stations start selling winter fuels?

For both fuels (automotive petrol, diesel fuel), the same winter period applies, not later than November 16 to February 28 or, respectively 29.

Do all petrol stations sell winter fuels?

The fuel quality at service stations must comply with the relevant standards (STN EN 228 for automotive petrol and STN EN 590 for diesel fuels). According to Decree No. 228/2014 Coll., which establishes requirements for fuel quality and maintenance of the fuel register, it is obligatory for each fuel retailer to sell fuels according to the relevant winter specification in the prescribed winter season. Control of compliance with the Decree is ensured by the Slovak Environmental Inspectorate. In addition, renowned dealers, including the Slovnaft network, offer premium diesel fuel that is able to resist much more challenging climatic conditions than standard diesel.

Is it possible that I can find out that I'm filling up with winter fuel?

A motorist who fills fuel at the service station can not see whether summer, transit, or winter petrol or diesel fuel flows from a glance at the measurement of the flow meter or tank gun. In any case, the vendor must provide the customer with the quality corresponding to the given period in accordance with the standards and regulations for automotive petrol and diesel. At Slovnaft service stations, customers have access to documents that also contain information about the fuel currently under sale. According to these documents, the customer can check what fuel is currently available at the relevant gas station.

What should you do should your car be standing in the garage and has not be driven for a long period of time?

Now, in winter, it is not appropriate to rely on diesel fuel refueled before November 16. Such diesel fuels may not yet contain the appropriate additives and their summer quality does not allow for the guarantee of trouble-free performance at long-term low temperatures. When exchanging summer fuel for the winter it is best to refuel with the smallest amount of old fuel in the tank. This minimizes the negative impact of summer diesel on the low-temperature performance of winter diesel.

Is it necessary to add special additives to the winter fuel?

Winter diesel in the Slovnaft service station network is contains all required additives and does not require the addition of additional additives. In addition, unverified additives mixed into fuel may not be compatible with the components in the fuel and may cause complications. Pre-conditioning of the fuel can also lead to a reduction in the effectiveness of the ingredients. The resistance of petrol to low temperatures is ensured by its composition and its characteristic properties, that is, gasoline does not freeze in winter. If the ignition system of the petrol engine is blocked, it is almost exclusively due to the presence of water in the fuel.

I did not refuel with winter diesel and I can not start the car now. What should I do?

The problem of starting a car in winter can be caused by several factors. Before the winter season, car owners should check the condition of the car battery, fuel filters, operating fluids (oil, coolant), and with diesel engines the functionality of the heaters. Of course, fuel quality can not be excluded either. If diesel is already stuck in the fuel system, the most appropriate solution is to move the vehicle to a warmer garage or service environment, or wait for the outside temperature to rise and the fuel becomes liquid again in its entirety. However, this process may take several weeks in an external environment. If a motorist is refueled with an inappropriate diesel fuel, we recommend that this fuel be discharged and to fill the tank with new winter diesel fuel. For extreme frosts (below -20 ° C), it is recommended to refuel with the premium diesel fuel EVO diesel, the quality of which is set to handle also Arctic temperatures below -40 ° C.

Why is it better to fill up the fuel tank to full in winter?

Water is fed into the fuel system through condensation of air humidity. Therefore, it is advisable to fill up the tank to full in the winter to reduce the amount of air in the tank. The precipitated water crystals at temperatures below 0 ° C can accelerate clogging of the filters.

Is it possible to mix common and premium diesel? Will the properties of conventional diesel improve?

Mixing of common and premium diesel is possible. Whether adding premium fuel improves blended fuel oil parameters depends, in particular, on the premium and common fuel ratio as well as on the qualitative parameters of premium diesel. EVO diesel premium fuel is also suitable for temperatures below -40 ° C.