So the cold winter and freezing arctic air is about to arrive. Temperatures are expected to drop well below freezing within a few days. Of course, this means minor (sometimes even major) complications for the operation of the car and the motorist. But if you are prepared, nothing terrible should befall you. Modern cars are designed to operate smoothly even in 30-degree frosts.

But this is only true if they are in good condition. But since many of us completely neglect our cars, do not deal with regular maintenance and only change the oil once in a while, it is not surprising that the car does not start in the morning or fails during the journey. Frost threatens several important components. So what about that?

The oil will solidify into a paste

Why does even a healthy engine in a well-maintained car have a harder time starting? The problem is mainly in the oil, which solidifies at very low temperatures and, to put it simply, has more resistance. We’ve covered the properties of oils in detail in our multi-part special on oils, so we’ll refer you to it.

In this special, we mentioned the analogy of a jar of honey. At room temperature, honey is almost impossible to mix (it has a high viscosity), but when you warm it, it becomes much easier to mix. It’s the same with engine oil. This is also why different winter oil classes are marked according to viscosity, i.e. fluidity, for example 0W-20, 5W-30 or even 10W-40 and the like.

Simply put, the winter class 0W has better pumpability at lower temperatures than, for example, 10W. There are tables for this and we present them in our “oil” series as well. We just remind you that even 10W oil according to the SAE standard has a maximum viscosity of 7000 mPa.sv -25 °C and pumpability at a viscosity of 60 000 mPa.s up to -30 °C. It should be more than enough for normal Czech winters. With a high-quality SAE 0W or 5W winter class oil, you should have no problem at all even at temperatures below -20 °C. Liquid will be enough.

Most likely, the flashlight will betray you

Batteries do not mind low temperatures, they suffer the most in the summer heat. The filling evaporates from them and their capacity decreases. It is not enough to charge fully, and when it is time to warm up before starting in the winter and especially when you need to turn the engine with congealed oil, the battery will no longer be able to do it.

Photo: Shutterstock / LizzavetaS

The battery weakens mainly due to the summer heat, but it is only in winter that it starts to cause problems. On short journeys, the battery also recharges more slowly, as the cars consume more energy due to the comfort appliances being switched on.

The condition of the battery can only be reliably verified by a load test in the service department, universal diagnostics will at most detect the same values ​​as a regular multimeter, which you surely have at home as a do-it-yourselfer. It’s not a bad idea to use the charger regularly if you don’t drive often, or on the contrary you only drive short distances and maybe start the car five times a day and only drive a few kilometers. The battery is not enough to recharge and practice says that you have to drive about 50 km to recharge the battery sufficiently.

For short journeys, limit the use of comfort appliances with a high consumption of electricity (seat heaters, windows, fog lights) and switch off the stop/start system. If you’re worried about reliability, carry jumper cables (and then hope someone helps you) or buy a backup battery “booster” to help the battery. But beware, commonly available boosters often do not revive a completely dead battery at all.

Do low fuel temperatures bother you?

You don’t have to worry about the problem of freezing with gasoline, at least in our climate. It’s worse with diesel. However, from 11/16 to 2/28, diesel fuel of class F, characterized by filterability down to -20 °C, is sold at our pumps. However, some pumps also offer so-called Arctic diesel, which has a filterability of up to -44 °C.

Foto: Shutterstock / R. Classen

Between November 16 and February 28, we sell so-called winter diesel with filterability down to -20 °C. However, you can also buy special arctic diesel somewhere, which can easily withstand minus forty degrees.

The problem with diesel is that in severe frosts, paraffin crystals form in it and then they clog the fuel system, most often the fuel filter circuit (it acts as a dam against which the large crystals crash). Then the car simply won’t start because the fuel isn’t going to the injectors. A heated fuel system is an advantage, but not all cars have it.

Prevention is best. You probably won’t be able to change the fuel filter in a hurry (even if it’s very accessible in some cars, it’s a five-minute job), so at least fill up on good quality diesel in time, or even the aforementioned Arctic diesel. You can also buy special winter additives that improve the filterability of diesel and move the freezing point to even lower temperatures. In the editorial office, we have good experience with winter VIF, but perhaps you have also tried some other additive. However, since temperatures are predicted to be down to -20 °C, ordinary diesel should probably be enough. The practice of pouring a few liters of gasoline into the diesel as protection against freezing is definitely not recommended for modern diesels with particulate filters and complex injection systems.

Just as diesel is winter and summer, LPG has a different composition in winter. Winter LPG has 60% propane and 40% butane, i.e. the reverse ratio compared to the summer mixture. Propane evaporates better (more precisely, the resulting mixture has a lower boiling point). A vehicle that is in good technical condition will have no problem running on LPG. It will just take longer to heat up the system in which the gas evaporates. The car will thus have a higher gasoline consumption and also a slightly higher gas consumption.

Other liquids can also betray

In cold weather, remember that the oil also solidifies in the gearbox and differentials. Therefore, shifting will be difficult, the automatic will not be wanted, and the differential will also take a while to warm up a bit. But other fluids are much more risky, especially the coolant and also the filling in the washers.

For washers, we remind you that it depends a lot on the quality of the liquid, but also on the surrounding conditions. Even if it is stated that it can be used down to -20 °C, it often freezes on the windows while driving, or the washers are no longer capable of reliably “sending” it to where it is most needed. Stocking up on high-quality antifreeze for the washers is a must before the winter season, we can repeat it over and over, but no one does it anyway. So you then buy overpriced liter bottles of liquid down to -40 °C at highway gas stations.

While you can theoretically manage without washers (at most you will have to stop from time to time and wipe the window manually), you can do without coolant at all. Owners of air-cooled cars have less to worry about, but regular water-cooled cars must of course have that water in liquid form. And that is sometimes a problem with poorly maintained cars.

You can find out the condition and ability of the liquid to withstand freezing with a hydrometer, any service will help with this. Even well-maintained cars tend to have fluid that barely withstands -30°C, many of us have low-quality fluid and diluted from the constant topping up of water from the summer, so we’re glad it doesn’t solidify below -20°C. So watch out for that. Even though some cars are protected against this, frozen liquid can destroy the engine (water expands in the cold).

Folk remedies to make life easier in the cold

Diluting diesel with gasoline: As stated above, while this method may have worked in some cars as protection against diesel freezing, it is not recommended for modern cars. There is a particular risk of damage to the sensitive injectors, which must be lubricated with diesel.

Covering the radiator: This is commonly done on older cars, but be careful with modern cars. If the car does not warm up to operating temperature, the problem will be elsewhere, most often in the thermostat. Also be careful in city traffic and queues. An engine that does not get air to the radiator will easily overheat.

Starting “with the clutch”: This is a bit of a controversial issue. In addition, many modern cars do not even allow starting without pressing the clutch. However, the axial bearings of the crankshaft should perhaps already be prepared for this in these cars. However, it can be a problem for older cars. The general rule of thumb is that if you can start without a clutch, do it. The habit of wringing out the clutch in cold weather mainly arose at a time when the oils were very viscous and the weak battery simply did not turn the engine and gearbox.

Warming up the engine at idle speed: Today’s cars are more harmed by this (dilution of oil with gasoline in direct injection engines) and they heat up faster during normal driving. The method of gradually warming up to idling is more relevant to old engines with cast iron blocks and heads, which were very sensitive to sudden changes in temperature. And even so, the engine warmed up better while driving. You just had to drive very sensitively and carefully. But you should be cautious with adding gas and revs even with modern engines before they warm up.

Pouring hot water over the windows: Watch out for this! We understand that you want to speed up the preparation of the car in the morning, but be careful with it. Anyway, it is first necessary to clean the windows from snow and larger pieces of ice with a scraper. For icing, if at all, you’d better use very lukewarm water. There shouldn’t be a problem with that. And then it is necessary to wipe it off immediately so that it does not freeze on the window again.

Making fire under the gearbox: This is a curiosity that is “enjoyed” especially in Russia and other countries where the temperatures are extremely low for a long time. Firstly, modern cars have a plastic covering on the chassis, secondly, solidification of liquids can be prevented by using high-quality oils. So yes, if you have an old UAZ somewhere in the Mongolian steppe, where it can easily be -45 °C in winter, you can use a fire under the differential and gearbox. But with us and a modern car, you really don’t have to do that anymore.