The engine oils for our climate zone
In this article, our expert associate Dr. Stevan Dimitrijevic will tell us more about the oils that are being used in our climate zone, specifically, about the SAE scale, the temperature range and the viscosity scale suitable for our climate. We warmly recommend that you read the following pieces of advice and the doubts that they often raise.
The region of Southeast Europe, which the Balkans and, therefore, Serbia, are a part of, is characterized by mild continental climate, with the minimal temperature of around -20°C, and the maximum temperature of around +40°C. If you take the 10 extreme winter and summer days out of the equation, it means that the temperature for the aforementioned region ranges from -15 to +35 °C. Mountain regions are the exception, seeing it as the temperature there drops all the way to -25 °C (in the Sjenica region, it drops to -35 °C), which we’re especially going to take into account.
Generally speaking, with the aforementioned in mind, the ideal SAE viscosity grading for a full year engine oil is:
- for the older generation of cars from the 1990-s, 15W-40 and 10W-40, and for the mountain regions 5W-40;
- for the middle-aged generation of cars from the 2000-s, 5W-30 or 5W-40, and for the mountain regions 0W-30/40;
- for the latest generation of cars from the 2010-s, for the whole Serbia, Balkan and Southeast Europe region, 0W-20 or 0W-30.
The most correct way to put it is that the selection of viscosity grading is, first and foremost, related to the engine’s construction and the manufacturer’s recommendation which takes your climate zone into account. This is why you should always consult your car’s owner’s manual which contains recommended viscosity grading values. 2 types of recommendations stand out:
- 1 viscosity grading as a given value, typical for some European manufacturers - the average climates characteristics of an entire continent are taken into account here, without extreme values, such as North Europe and regions with a Mediterranean climate (in some cases, an alternative viscosity grading is recommended for very low temperatures, rarely for very high ones);
- the aforementioned viscosity grading which comes as a primary recommendation, with a table containing recommended viscosity grading for different temperature ranges - this is typical for Japanese manufacturers, even for those which have their production lines located in Europe.
It is important to know that one shouldn’t use the few extreme days of the year as a standard - they should go by the common minimum and maximum temperatures.
So, modern cars usually have 1 (primary) viscosity grading which is most often recommended for a temperature range between - 30 and + 40 °C, which covers practically entire Europe’s territory.
These are usually easy-flowing engine oils with low viscosity grading. When it comes to European manufacturers, most of the time it’s either 5W-30 or 0W-30, and in the case of American and especially Japanese manufacturers, it’s either 5W-20 or 0W-20 (as of lately, 0W-16 also).
Due to the trend of reducing internal resistance, the SAE J300 standard, which defines engine oil viscosity and engine oil viscosity grading, was expanded in 2015 to the future 0W-12 and 0W-8 engine oils.
In the case of the new generation of engines, the use of more viscous engine oils can be counterproductive, seeing it as lubricating bearings with 5W-40 can already be significantly poorer. This is why one should not overestimate summer heat and a few days with the temperature going over +35 °C, as these are not the reasons for switching to a more viscous engine oil. The exception comes in the form of you living or residing for lengthy periods of time in a littoral region, for example in Monte Negro, when potential switching from 5W-30 to 5W-40 of the same quality is justified.
Not going by the manufacturer’s recommendation (default values) can only be taken into consideration in the following cases:
a) normal driving conditions - a lower value W for mountain regions, especially when switching from 10W-40 to 5W-40, whereas for exceptionally low temperatures, switching from 5W-40 to 0W-40 or from 5W-30 to 0W-30 (5W-xx is enough for - 25 °C) is fine. For a use that lasts longer than a few weeks, in regions characterized by high temperatures, it is possible to switch from 0W-30 to 5W-30, or potentially from 5W-30 to 5W-40, especially when it comes to vehicles which are 5 or more years old (in particularly 10);
b) short city distances - as is the case with the aforementioned example, but also in the case of higher minimum temperatures. Potential switching to 0W-xx, at a temperature of - 20 °C, as well as to 5W-xx at - 15 °C. Increasing viscosity is not a necessity, not even for temperatures up to + 40 °C (+ 50 °C in the sun);
c) long highway drives, characterized by a high RPM (and/or occasional visits to a runway, Truck Day type of manifestations and similar events), and heavy exploitation conditions - switch to less viscous engine oils only when you cross the W mark use limit, when being exposed to high temperatures for lengthy periods of time (it starts at +30 °C). Switching to a more viscous grading can be considered, as stated under “a”.
For all of the above the following applies: these are not recommendations, but simply options. When the engine is in good condition, in all 3 cases you should stick to the original recommendation, especially if it’s 5W-30 or 5W-40. When it comes to modern engines, the tolerance is small, meaning 5W-30 is enough for a temperature of +40 °C in the shade, seeing it as 5W-40 covers climate zones with temperatures ranging from -25 to +45 °C in the case of most engines, even those with slightly older construction.
We hope that you’ve found this article useful. For any questions, unknowns and suggestions you may have, please, feel free to contact us.