For a long time, official distributors did not dare to supply cars with diesel engines to the Ukrainian market — the quality of local fuel left much to be desired. The problem was especially acute in winter: fuel system filters of common rail engines instantly clogged with paraffin when summer fuel was used. Our own checks regularly confirmed this — finding normal winter fuel was a real challenge. It is clear why dealers were cautious: one such refueling could kill the high-pressure fuel pump, the repair of which sometimes costs more than half the price of the car itself.
Twelve contenders for the title of winter fuel
We decided to cover as wide a range of operators as possible, collecting samples from both budget chains and global brands, from market newcomers and veterans. Heavy fuel from Kyiv gas stations WOG, OKKO, KLO, Amic, ANP, Chipo, Glusco, Marshal, Motto, Shell, Sunoil, and BRSM-Nafta was sent to an accredited laboratory. In addition to regular grades, we also tested proprietary blends with various additives. The analysis was carried out according to five key criteria specified in GOST 7688:2015: cold filter plugging point, water content, cetane index, sulfur level, and density.
How much does fuel "freeze"
Motorists are most concerned about how diesel will behave in frost. The times when fuel lines had to be thawed with blowtorches are not yet forgotten. The mentioned standard clearly divides fuel into summer and winter depending on the temperature at which it loses fluidity on the filter. For summer fuel, the threshold occurs at -5 °C, for winter fuel — at -20 °C. The same document limits the water content in fuel to no more than 0.02%. Otherwise, at sub-zero temperatures, ice crystals will clog the filter and tubes no worse than frozen paraffin. Although no water was found in any of the submitted samples (this indicates proper logistics and storage), only eight out of twelve can be called truly winter. It is pleasant that WOG and OKKO fuel thickened only at -30 °C, and two more samples (Chipo and Motto) fell just one degree short of the "arctic" mark.
Cetane indicators
Another important criterion is the cetane index, which shows how additives affect the cetane number. The higher it is, the easier it is to start the engine in cold weather and the more stable it runs. This time, no one had problems with the minimum threshold of 46 units. And again, WOG and OKKO demonstrated the best margin of safety, and BRSM-Nafta and Chipo also performed well.
Energy density
If there is never too much cetane, then the density of diesel fuel (and hence the amount of energy released) must be within strictly specified limits. According to GOST 7688:2015, at 15 °C the density should be 820–845 kg/m3. And again, all twelve samples fit perfectly into this range.
Who is at risk
The most important environmental indicator is sulfur content. When burned, it forms acids that not only clog catalytic converters and the fuel system but also harm the respiratory tract. Previously, high sulfur content was overlooked due to its lubricating properties, but with the advent of more advanced and safer additives, they began to actively combat it. With each new environmental standard, it becomes less: Euro-3, adopted in 1999, allowed 350 ppm (mg/kg), and the Euro-5 currently in force in Ukraine, introduced ten years later, allows only 10 ppm. Although all samples met the standard, the spread on this indicator is significant. The leaders (OKKO, WOG, Chipo, Motto) showed 3-4 mg/kg, while Glusco and Marshall were at the very limit — 10 mg/kg.
In winter, diesel owners can sleep peacefully
The test results show that the quality of diesel fuel at domestic gas stations is at an unprecedentedly high level, and in a number of parameters even meets Euro-6 standards, the introduction of which was postponed for another year. But most importantly, no one is risking selling summer fuel in cold weather anymore, which used to happen quite often.
Alexander Babenko
