How to choose motor oil for your car: tips for drivers

To ensure that your car's engine retains good performance for many years and thousands of kilometers, it needs to be equipped with high-quality engine oil that is suitable for its characteristics. As a rule, its characteristics are regulated by the car manual. But you can figure out all the nuances on your own so that you never make a mistake with your choice.

OBOZREVATEL asked professional mechanics for their recommendations. Here's what they advised to pay attention to.

How to determine the right viscosity

The viscosity of the oil determines how it will lubricate the engine in different temperature conditions. It becomes thicker in winter frosts and thinner in summer heat. The viscosity level is determined according to the SAE specification and is labeled with the letter W, i.e. Winter. On packages with technical fluid, you can see such markings as 5W-40, 10W-40, etc. The number before the letter W indicates how easily the oil will flow to the engine parts in cold mode and how much battery power will be spent on the starter motor (viscosity at 40°C). The summer viscosity grade is indicated after the dash. It indicates what this figure will be at an engine temperature of 100°C.

Automakers allow the use of oil with a viscosity that differs from the recommended one by 5-10 units. Since winters in Ukraine are relatively warm, you don't need to choose an oil with a very low winter index. But the "summer" value can be taken from the maximum allowed by the car manual.

How to choose a quality class

The quality class is an indicator that can be used to determine the suitability of an oil for use in engines with a certain load on parts. With each successive generation of cars, these requirements are increasing, so you need to choose a fluid that is not lower than a certain class. Also, newer developments are able to be safe for catalysts and exhaust system filters, ensure proper combustion in the cylinders, help save fuel, and have some other additional functions.

There are several oil quality class standards on the market. Among them are API, ACEA, JASO, and ILSAC. The most common in Ukraine is the API standard of the American Petroleum Institute. It divides these liquids into those intended for gasoline engines - they belong to category S, and diesel engines - category C. Within each category, there are classes. They are designated by letters of the Latin alphabet, starting with A.

The most common class of oils for diesel engines is CF. They can be used in high-powered diesel engines, both with and without turbocharging.

When choosing, it is also important to consider that the oil is compatible with modern exhaust gas treatment systems (limited SAPS). Another key indicator for diesel engines is that the fluid does not damage the DPF particulate filter in the exhaust.

As for gasoline engines, the classification is more complicated. According to API, there are several classes: SJ, SL, SM, SN and the most modern SP. The latter is the most stable, has less volatility and a good resource for extended service life before replacement. However, the latter should be based on the car manufacturer's recommendations.

Oils can be divided by quality class according to the ACEA system. Here, category A is assigned to gasoline engines, category B to diesel engines, and category C includes low-ash oils that are compatible with modern exhaust gas neutralization systems - we are talking about the previously mentioned diesel DPF and gasoline TWC. The numerical index in the ACEA classification indicates the quality class of the oil, for example, ACEA C3, ACEA C4, and so on.

It is important to keep in mind that some modern oils that have been developed for use in vehicles with multi-stage exhaust aftertreatment systems cannot be used in older generations of engines. When choosing, you need to check the instructions for a particular car.

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