This year, December surprised us with abnormally warm weather, but after the holidays, winter came into its own. Thermometers dropped to minus 20 degrees, and many diesel cars turned into motionless "sculptures." Low-quality fuel thickens in severe frost, clogging filters and depriving the car of the ability to move. That is why experts from the Institute of Consumer Expertise decided to find out what diesel fuel is currently sold at Ukrainian gas stations and which networks can be trusted in the cold.

Testing
IPE specialists purchased fuel from well-known brands and unbranded fuel from eight networks located in different regions of the country. In total, 10 samples were delivered to the laboratory, the full list is provided below. Each sample was tested for four parameters: resistance to freezing, cetane number, sulfur content, and flash point. The first two indicators are critically important in winter.

Two samples out of ten had serious violations — these are the MC Oil card and Sun Oil networks. At the same time, there were also clear winners. The best frost resistance indicators were demonstrated by Perfeкt Diesel Arctic (Parallel network) — down to minus 33 degrees, and Pulls Diesel Arctic (OKKO network) — below minus 33 degrees Celsius. Details below.

Cold resistance
Measurements of the cold filter plugging point showed that all purchased samples belong to winter grades. Moreover, some of the fuel turned out to be arctic and freezes only at temperatures below minus 28. The answer to the question of why we need arctic fuel in our climate is obvious: a margin of safety in the tank never hurts, as recent cold snaps have confirmed.

The absolute records for frost resistance were set by: Parallel (Perfeкt Diesel Arctic) — minus 33°C, KLO (Ventus diesel) — minus 28°C, and OKKO (Pulls Diesel Arctic) surpassed everyone — below minus 33 degrees Celsius. The remaining participants, whose fuel meets the standards, showed results from minus 15 degrees and below (Sun Oil (Euro DT) and MC Oil Card (DT Euro)). Thus, in terms of frost resistance, all samples turned out to be winter-grade, but most "regular" grades will still freeze at minus 20.

Do not forget that weather changes rapidly in winter, and a cold snap can arrive suddenly. Moreover, thermometer readings do not always reflect the real perception of cold — in wind and humidity, frost feels stronger. Therefore, IPE experts advise diesel car owners not to take risks already at minus 15 and to use arctic fuel.

Cetane number
This parameter shows how quickly the fuel mixture ignites — the time from injection to the start of combustion. A low cetane number makes the engine run harder, increases fuel consumption and exhaust smoke. In cold weather, a high cetane number contributes to efficient engine operation and easy starting. Usually, there are many complaints about this point, but this time everything went smoothly.

All participants showed decent results. The highest indicator is from OKKO (Pulls Diesel Arctic) — 52 units. Sulfur Sulfur content is the main indicator of diesel fuel's environmental friendliness. The products of its combustion harm both nature and the engine. Sulfur is equally dangerous at any time of year. Ukrainian standards allow different amounts of sulfur depending on the type of fuel. For type II (Euro-4), the limit is 50 mg/kg, for type I (Euro-5) — no more than 10 mg/kg. Here, experts were in for a surprise. The results turned out to be extremely heterogeneous. Two samples did not even reach "Euro"!

Fuel from the Sun Oil and MC Oil Card networks turned out to be very "dirty" — 447 and 679 mg/kg, respectively, with a standard of no more than 50! This is a clear deception of buyers, because such fuel has no right to be called "Euro." The remaining samples pleased — all samples had no more than 10 mg/kg of sulfur! And the minimum content of the harmful substance was recorded in Parallel (Perfeкt Diesel Arctic), KLO (Ventus diesel), LUXWEN (DT Euro) and OKKO (DT Euro and Pulls Diesel Arctic) — only 3 mg/kg each!

Flash point
The last parameter important for our test is the flash point in a closed crucible. It reflects the ignition temperature of the fuel and indicates its fire hazard. If this indicator is below the norm, it may indicate the presence of light fractions in the diesel fuel. Violations were found in Sun Oil and MC Oil Card.

Conclusions
The main conclusion of the study: despite the difficult economic situation, declining demand and the devaluation of the hryvnia, there are traders on the market who continue to maintain the quality bar. Diesel car owners need not fear the cold — the main thing is not to chase cheapness and refuel at stations that reliably monitor quality. And, of course, keep an eye on the weather forecast. In severe frosts, only arctic "diesel" should be poured, since only it will ensure trouble-free driving.

Yuriy Gribenko

Reference: Diesel fuel does not tolerate low temperatures well due to paraffinic hydrocarbons with a high pour point. For example, in summer fuel, paraffin begins to precipitate already at –5°C (cloudiness appears). At –10°C, summer diesel thickens and clogs filters. Winter fuel is more frost-resistant: the cold filter plugging point for grade E (DSTU 4840:2007) is not higher than minus 15°C, for grade F — not higher than minus 20°C. The new DSTU also provides requirements for diesel fuel intended for arctic climates. In this case, DT EURO is divided into classes: class 0 — cold filter plugging point minus 20 °C; class 1 — minus 26 °C.