Engine oil viscosity grade - what determines and how to read the marking?

Are you looking for engine oil, but the labeling on the specs of specific products means nothing to you? We came to the rescue! In today's post, we decipher the complex codes that appear on engine oil labels and explain what to look for when choosing a lubricant.

Shortly speaking

Viscosity is how easily an oil passes through an engine at a certain temperature. It is determined by the SAE classification, which divides lubricants into two classes: winter (indicated by a number and the letter W) and high-temperature (indicated by a number), which indicates the temperature created by the operating drive.

SAE oil viscosity classification

We always stress that the first step in choosing the right engine oil should be validation. vehicle manufacturer recommendations... You will find them in your vehicle's instruction manual. If you do not have one, you can use online search engines that will help you choose oil by car make and model, as well as engine parameters.

One of the most important characteristics of a lubricant, described in detail in the car's instruction manual, is viscosity. It determines how easily oil will flow through the engine at a specific temperature.both with the internal, formed during its operation, and with the ambient temperature. This is an important parameter. Correctly selected viscosity guarantees trouble-free starting on a frosty winter day, fast oil distribution to all drive components and maintaining the correct oil film that prevents the engine from seizing.

The viscosity of engine oils is described by classification Association of Automotive Engineers (SAE)... In this standard, lubricants are divided into winter (indicated by numbers and the letter "W" - from "winter": 0W, 5W, 10W, 15W, 20W, 25W) and "summer" (described only by numbers: SAE 20, 30, 40, 50, 60). However, the term "summer" here is a simplification. The winter gradation actually indicates the oils that can be used in winter when the thermometer drops a lot. "Summer" class is determined based on minimum and maximum lubricant viscosity at 100 ° C, and the minimum viscosity at 150 ° C - that is, at engine operating temperatures.

Currently, we no longer use plain products adapted to the season. In stores you will find only multi-grade oils, designated by a code consisting of two numbers and the letter "W", for example 0W-40, 10W-40. It reads like this:

• the smaller the number in front of the “W”, the less oil will hold high fluidity at subzero temperatures – reaches all engine components faster;
• the larger the number after the “W”, the more oil is retained. higher viscosity at high temperatures generated by a running engine – better protects drives subjected to high loads, as it coats them with a thicker and more stable oil film.

Types of engine oils by viscosity

0W-16, 0W-20, 0W-30, 0W-40

0W class oils clearly outperform their competitors in terms of viscosity retention at low temperatures - ensure optimum engine starting even at -35 ° C... They are thermally stable and resistant to oxidation, and thanks to advanced production technology, they can reduce fuel consumption. Among the lubricants of this class, the most popular is 0W-20 oil, which is used by the Honda concern as the so-called first factory flooding, and also dedicated to many other modern Japanese cars. 0W-40 is the most versatile - it is suitable for all vehicles whose manufacturers allow the use of lubricants 0W-20, 0W-30, 5W-30, 5W-40 and 10W-40. This is new Oil 0W-16 - appeared on the market relatively recently, but has already been evaluated by Japanese manufacturers. It is also used in hybrid vehicles.

5W-30, 5W-40, 5W-50

Engine oils from the 5W group are slightly less viscous - ensure smooth engine start at temperatures down to -30 ° C... Drivers liked the types the most 5W-30 and 5W-40... Both work well in freezing temperatures, but the second is slightly denser, so it will work better on older, worn cars. In engines requiring a stable oil film, oils with even higher high-temperature viscosities are often used: 5W-50.

10W-30, 10-W40, 10W-50, 10W-60

10W oils remain viscous at -25 ° Ctherefore they can be safely used in our climatic conditions. The most popular ones are 10W-30 and 10W-40 - are used in most cars on European roads. Both can withstand high thermal loads and help keep the engine clean and in good condition. Oils 10W-50 and 10W-60 They are used in vehicles that require more protection: turbocharged, sports and vintage.

15W-40, 15W-50, 15W-60

For vehicles with high mileage, engine oils of the class 15W-40 and 15W-50which help maintain optimal pressure in the lubrication system and reduce leakage. Products marked with 15W-60 however, they are used in older models and sports cars. Oils of this class allow the car to start at -20 ° C.

20W-50, 20W-60

Motor oils of this class are characterized by the lowest viscosity at low temperatures. 20W-50 and 20W-60... Nowadays, they are rarely used, only in older cars built between the 50s and 80s.

Viscosity is an important parameter of any lubricant. When choosing an oil, strictly follow the recommendations of your car manufacturer - the product you have chosen must “fit” the system: play between individual elements or pressure in it. Also remember that in this case the savings are only obvious. Instead of cheap nameless oil from the market, choose a well-known brand product: Castrol, Elf, Mobil or Motul. Only this lubricant will provide the engine with optimal operating conditions. You can find it at avtotachki.com.