Arctic temperatures are currently holding Europe under control. But at temperatures as low as -25 degrees, not only do people get cold, cars also freeze. This is currently particularly evident in vehicles with diesel engines, which are increasingly capitulating to the cold. The ADAC reports a drastic increase in the number of cold victims among diesel drivers, especially from the winter sports areas, but also in the lowlands, the workshops currently have their hands full looking after stranded diesel drivers. Towing services report a boom all over the country.
A urn it hit us too. A Land Rover Defender, which is currently in the editorial office as a test car, largely ceased operations after a cold night. As soon as it got above idle speed, the engine died. Diagnosis: Sulz diesel. It wasn't even really extremely cold - the Defender had spent a night at -15 degrees in an outdoor parking lot. The answer to the riddle is the particularly exposed diesel filter on the Defender (see picture gallery). But the cold is also making it difficult for other brands.
The current cold is not a phenomenon of the century, even in the past winters it was always bitterly cold. That is why it is currently hotly debated among diesel drivers whether the significantly increased admixture of so-called biodiesel to regular diesel fuel since 2010 is a trigger for the enormous increase in breakdown frequency in recent days. Above all, the increased hygroscopicity of biodiesel is discussed - in German: the vegetable fuel absorbs more water, which freezes out in extreme cold and can clog pipes and filters /strong>
The reason for starting and driving difficulties in diesel cars at extremely low temperatures, however, is generally the fouling of the fuel. It is true that the so-called 'winter diesel' is prescribed by the legislature from November 16 to February 29, which should be resistant to cold temperatures down to minus 20 degrees. However, this temperature can often be fallen below in depressions or over snow-covered areas. In addition, it may well be that at a less frequented small petrol station even larger amounts of 'transitional diesel' with only up to minus ten degrees frost protection were stored in the underground tanks. The result is paraffins that flocculate and look like tiny flakesCandle wax clog the diesel filter and thus block the fuel supply.
Once the diesel fuel has melted, there is no 'quick' help on site. The entire fuel system must be warmed to above freezing point in order to dissolve the flocculated components. To do this, the car must be thawed in a heated workshop or garage. In addition, the diesel filter may have to be replaced to rectify faults.
Important for modern engines: do not add petrol!
Especially with modern diesel engines, the old 'trucker' should definitely not be used -Trick 'can be used to refuel a certain amount of gasoline. Modern injection systems and high-pressure pumps react extremely sensitively to the reduced lubricity of the fuel, which results in very expensive damage.
At the current temperatures, it can be helpful to refuel the expensive premium diesel from branded petrol stations, which, according to the manufacturers, is down to minus 35 degrees should be resistant to the cold. An alternative is to add flow improvers when refueling. Commercially available flow improvers reduce the cold suitability of winter diesel to temperatures below -30 degrees. It is important that the flow improver is filled in immediately before refueling. Subsequent admixing of diesel that has already become gelled does not help.
In order to be prepared for future failures, it is advisable to adhere to the change intervals for the fuel filter specified by the manufacturer. Dirty filters clog faster with clogged diesel. An electric filter heater can also be retrofitted relatively inexpensively in a specialist workshop in almost any diesel vehicle. If you do not have a garage available as a lantern parker, you should at least make sure that the car is parked in a sheltered place and not over snowy or icy surfaces, where temperatures can be even lower. Important: At the current temperatures, a warming blanket should be in the car to protect yourself against the cold in the event of a defect. Because if the engine is stopped because of a melted diesel, there is no longer any vehicle heating until help arrives. And that can take a few hours with the current days of cold and chaos.