The engine oil takes over the tasks of lubrication, cooling and sealing in combustion engines. Lubrication of the mechanical components is also protection against corrosion. The combustion processes taking place in the engine lead to residues that contaminate and thicken the engine oil. But also dust and tiny metal abrasion get into the oil circuit over time. Cars that are often only on short journeys do not reach the temperature to completely evaporate the fuel. Thus the fuel enters the engine oil circuit and leads to a dilution of the oil. That is why it is important to observe the maintenance intervals of the vehicle manufacturers and to change the engine oil regularly!
In the past, engine oils were changed according to the season, today multigrade oils are common. The viscosity reveals how liquid the engine oil is. The oil should be thin enough during a cold start to lubricate all parts quickly and still offer a high degree of lubrication reliability when hot. The smaller the number before the W, the more fluid the engine oil is in cold condition. The larger the number after the W, the more viscous the oil is even at higher temperatures. This is measured by the flow behaviour in relation to the reference temperature of 100°C. By the way, the W stands for "winter suitability". A high viscosity therefore means that the engine oil is more viscous. If the engine oil is more fluid, it has a lower viscosity. However, the viscosity does not say anything about the quality of the engine oil. If engine oil has to be topped up on the road, it is important to use the same viscosity grade (SAE) as the old one and to ensure that the same specifications are used. Engine oils with different SAE classifications should not be mixed together. Different oils could cancel each other out in their performance due to their different properties and thus impair functionality. In the following tables, the SAE classes are clearly presented once:
|SAE Class||Minimum temperatures|
|SAE 0W||-35 °C|
|SAE 5W||-30 °C|
|SAE 10W||-20 °C|
|SAE 15W||-15 °C|
|SAE 20W||-0 °C|
|SAE Class||Minimum viscosity at 100°C|
|SAE 20||6,9 mm²/s|
|SAE 30||9,3 mm²/s|
|SAE 40||12,5 mm²/s|
|SAE 50||16,3 mm²/s|
|SAE 60||21,9 mm²/s|
To buy the right engine oil, other specifications are important in addition to the SAE class such as 05W30. Which engine oil is suitable for your vehicle depends, among other things, on the American API specifications or the ACEA specifications relevant for the European region. Depending on the engine design, the ACEA specifications are differentiated between the A-, B-, C- and E-class:
These ACEA specifications describe the performance of the engine oil based on engine test runs in the test laboratory. Meanwhile, the ACEA specifications have been expanded. There are since May 2021 also A7/B7 for High-SAPS engine oils (sulfated ash-phosphorus-sulfur basis), which are suitable for vehicles without particulate filters and in contrast also the new specification C6 for Low-SAPS engine oils, which were developed for vehicles with particulate filters. These new versions are intended to further address the increased demands placed on modern engine oils. In particular, the focus is on Low Speed Pre-Ignition (LSPI), wear protection and turbocharger cleanliness. LSPI is a challenge arising from the "downsizing" of engines: more power, low displacement, high boost pressure. The aim is to reduce emissions and combine the demand for higher engine performance with the increased demands on the engine oil.
Due to the introduction of the new ACEA specifications, the old A3/B3 and C1 sequences will no longer be used for this purpose. However, there is a transition period until April 30, 2023, during which engine oil manufacturers may still use the old version. During this period, manufacturers will adapt their oils to the new ACEA specifications and relabel their products. Fuchs, for example, already has an engine oil that meets the C5/C6 requirements. This is the TITAN GT1 Flex 5 SAE 0W-20. However, it will take some time for a corresponding labeling.
In addition to the specifications already mentioned, however, most vehicle manufacturers have their own requirements above and beyond these international classifications. The specifications of the respective manufacturer are related to the different engine concepts as well as tests of the vehicle manufacturers themselves. Depending on the manufacturer, the designations are structured differently; the following are a few examples:
|Vehicle manufacturer||Examples of manufacturer approvals|
|VW standard||VW 502 00, VW 504 00|
|BMW standard||BMW Longlife-12 FE, BMW Longlife-01|
|FORD standard||WSS-M2C 925-B|
|Mercedes-Benz standard||MB 229.5, MB 228.3|
These manufacturer-specific standards are necessary for determining the appropriate engine oil. They are also relevant in the context of warranty claims, because they can only be asserted with the right engine oil. In the operating and operating instructions of your vehicle you will find the manufacturer approval of your vehicle manufacturer.
At every oil change, the engine oil filter should also be replaced, because it catches the residues of the engine oil. The engine oil should be changed at the specified service intervals of the respective manufacturer. You will find oil change sets for this purpose, which are tailored to the respective vehicles. These contain the appropriate engine oil in various quantities together with the matching engine oil filter. The required quantity can also be found in the operating instructions or in the service booklet. If you wish to store an opened container after an engine oil change, it is advisable not to allow the storage to exceed one year. The waste oil must always be disposed of properly.
In addition to the condition of the oil, the oil level must also be checked again and again. The engine oil is consumed over time. This is because the moving parts are not 100% gas and oil tight. This means that there is always a constant if very low oil consumption. In addition, some of the oil in the combustion chamber also evaporates and burns. It is therefore advisable to check the oil level at regular intervals and especially when driving for a long time, and to top up the oil if necessary. There are larger fluctuations if an oil leak has occurred. You can recognize this by the fact that a pool of oil forms under the car. Then the vehicle should be checked immediately in a garage.
Good engine oil ensures good lubrication and thus reliable engine running and safety. With us you will find high-quality engine oils of well-known manufacturers at a favourable price. If you are unsure which oil is suitable for your vehicle, please contact our customer service with the 17-digit chassis number.