Surprising functions of oil in modern engines

It doesn't just lubricate!

17 stycznia 2024

Oils can be successfully selected for older car models based solely on viscosity class. For newer models, API or ACEA specifications are the minimum. It is best to follow the approvals - or if you prefer - the car manufacturer's approval. It is no accident that every manufacturer of branded oils offers at least several versions of the „same oil” within one viscosity class, but with different approvals. TotalEnergies explains what this means and why it is so important for modern engines.

For many years, engine oil performed three main tasks. Firstly, it lubricated, secondly, it cooled and thirdly, as far as possible, it prevented the formation of deposits. In the past - at least in Poland - there was not a huge selection of oils. As far as possible, drivers tried to use „thinner” oils in winter and „thicker” oils in summer. And the cars like FSO Polonez and Fiat 126p and 125 proudly had stickers of branded oils bought for foreign currencies on their windows.However, time passed, market realities have changed, and the requirements of engine manufacturers also evolved. With the development and popularization of cam rockers with valve clearance self-adjustment, it turned out that engines equipped with this feature require oils of a specific viscosity class, at least 10W-40. Failure to comply with this requirement prevents the self-regulators in question from functioning properly because they cannot fill properly with oil.

Modern oils must fulfil incomparably more functions than their predecessors, and disregarding factory standards has much more serious consequences than just accelerated wear of camshafts. It may be hard to believe, but extreme deviation from the vehicle's operating instructions can result in complete wear and tear of the engine after just a few thousand kilometres (if not earlier). For this reason, the oil viscosity class itself becomes a completely insufficient parameter to fully determine the properties of a given lubrication.

For example, TotalEnergies offers as many as 7 different oils in the 0W-20 class alone! They differ only in the approvals of engine manufacturers.

The oils are developed together with engine designers

To put it simply, we can assume that TotalEnergies, like other oil experts, develops the composition of its lubricants together with engine designers. Matching oil of a certain viscosity class to a specific engine, e.g. 0W-20 or 0W-16, is only a preliminary procedure that begins the tedious process of enriching the oil with the appropriate additive package. These additives play such an important role that replacing 0W-20 oil approved by Mercedes with 0W-20 oil approved by e.g. BMW could bring disastrous consequences for both engines - it simply cannot be done.Of course, some oils meet the requirements of various manufacturers and are safe for several drive units, but then the packaging contains information about a larger number of approvals.

The oil is supposed to protect, even when it is cold

The first important thing is to match the oil to a specific lubrication system. More and more engines are designed so precisely that changing oil parameters can lead to a sharp drop in pressure in the drive unit due to disruption of the oil pump. Reckless pouring of lubricant with a viscosity class other than that permitted by the manufacturer may result in significant wear of engine components. This is especially important in vehicles equipped with a start-stop system and in hybrids (especially plug-in hybrids, which can turn on a cold combustion engine when the car is already on a fast road).

These requirements, combined with the desire to reduce internal operating resistance as much as possible, have resulted in some generations of drive units having virtually no tolerance when it comes to engine oil. Only one viscosity class is allowed and, very importantly, with a specific additive package that guarantees the maintenance of certain parameters over the entire temperature range and the strength of the oil film in areas of increased pressure (e.g. timing system, connecting rods, etc.).

Protects against knocking combustion

Another unusual requirement for the oil is the reduction of LSPI. The LSPI (Low Speed Pre-Ignition) phenomenon is the occurrence of self-ignition at low engine speeds. It is a serious problem in modern gasoline engines with direct injection and turbocharging. LSPI results from the appearance of an additional source of ignition in the form of burning fuel mixed with oil at the edge of the piston or any hot spot in the combustion chamber. The latest oils from the Quartz range, thanks to their composition, have an „extinguishing” effect on the amount of burning fuel and ensure the cleanliness of the combustion chamber. Thanks to this, they reduce the engine's tendency to LSPI. Using oil with the same viscosity class, but with a different approval, i.e. with a different additive package, may cause knocking problems!

Prevents soot deposits and protects timing chains

Thanks to appropriate additives, modern oils have a unique ability to disperse soot. This means that they capture soot that ends up inside the engine and keep it inside the oil volume, preventing it from settling inside the engine. Some of this soot is captured by the oil filter, but the rest circulates with the oil without impairing its lubricating properties (of course, for the recommended period between oil changes).

It used to be that soot was only a concern for diesel engines. Currently, „thanks to” downsizing technology, soot also appears in gasoline engines. This is why the latest petrol engines are equipped with adapted particulate filters (GPF). Soot-catching oils are essential for the proper functioning of these units. Interestingly, oil with strong dispersion properties actually extends the life of the timing chain because it protects the links against soot, and thus against the connections wearing out and the chain lengthening. Here, too, the characteristics of the oil result from the composition of additives, and not from the viscosity class itself. Therefore, also in this case, the appropriate approval of the engine manufacturer will be of key importance for the selection of oil.

Wet timing belt – an additional challenge for the oil composition

More and more engine manufacturers enclose timing belts in one housing with the entire engine. The timing belt is then washed with oil. The designers' intention was to extend the life of such a belt by protecting it against contamination and to lubricate the places where the belt contacts the timing pulleys, reducing adhesive wear. In such cases, when homologating the oil, the designer checks the compatibility of the oil with the belt material so that it does not dissolve. Therefore, no designer allows the use of conditioning agents added to the oil in such cases, as they may negatively affect the life of the belt.

DPF protection by limiting the ash content

This is a very popular topic, but it is worth mentioning again. All engines equipped with particulate filters require low-ash oils, i.e. oils that do not create too much sulphate ash when the particles remaining in the cylinders are burned. In this case, all Quartz oils from the INEO range with the ACEA C standard contain low-ash additives that extend the life of the components of exhaust gas treatment system . In the case of other manufacturers, assigning a specific standard to the entire range of oils does not have to be the rule and this is another reason to pay attention to the manufacturer's approval when choosing oil.

It can be safely said that using oil for a modern engine without the appropriate manufacturer's approval (only based on quality or viscosity class) may cause serious failures. As you can see, they will not always concern only the lubrication system. Poorly selected oil may cause knocking combustion, clog the particulate filter or shorten the life of the timing chain or timing belt.

Andrzej Husiatyński, TotalEnergies

About TotalEnergies Marketing Polska:
TotalEnergies Marketing Polska has been operating in Poland since 1992 and has an established position on the engine oil market. It offers products of two well-known brands TotalEnergies and Elf. Since 2008, TotalEnergies also offers bitumen products and is present in the market of industrial special fluids. The company has also been operating on the fuel sales market since 2009. In 2021, TotalEnergies opened the first car washes and launched a project to create a charging network for electric vehicles.

About the TotalEnergies Marketing Services:
TotalEnergies Marketing Services offers its professional and private customers a wide range of energy products and services - petroleum products, biofuels, charging and related services for electric vehicles, road and marine gas - to support their mobility and help them reduce their carbon footprint. Every day, over 8 million customers visit our 16,000 service stations around the world. Number four in the world in lubricants, we design and market high-performance products for the automotive, industrial and marine sectors. In order to best respond to the needs of our B2B customers, we deploy our sales force, our international logistics network and our diverse offer. We operate in 107 countries, where our 31,000 employees are close to all our customers.

About TotalEnergies:
TotalEnergies is a multi-energy concern that produces and sells energy on a global scale: oil and biofuels, natural gas and green gas, renewable energy sources and electricity. Our 105,000 employees are committed to creating ever cheaper, clean, reliable and accessible energy to as many people as possible. Active in over 130 countries, TotalEnergies focuses on sustainable development in all its dimensions, in particular in the area of its projects and business operations, which are to contribute to increasing the quality of life of people around the world.

Contact TotalEnergies:
Bartosz Cyran | bartosz.cyran@proautomotive.pl | +48 662 454 679.

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