Description:
5 min
Additives in engine oil: Is it good or bad?
Engine oil additives are special formulations designed to reduce oil consumption, increase compression in cylinders, and perform other beneficial functions for gasoline and diesel engines. How do additives work, what types exist, and are they beneficial?
The primary goal of additive manufacturers (including Liqui Moly, Hi-Gear, Fenom, Suprotec, and XADO) is to restore worn engine components to their factory specifications, reduce oil and fuel consumption, and extend the lifespan of engines without significant wear. Research results indicate that some miraculous formulations can even enhance engine performance.
Types of additives
Let's start with the types of additives for motor oil. First and foremost are compositions with a kind of restorative effect achieved by creating a protective layer on internal engine parts, sometimes referred to as nanoceramic. It consists of metals, organic compounds, ceramic particles, and helps reduce clearances and partially restore compression to factory values.
Let's consider the description of anti-wear additives and their effects using examples from some Liqui Moly products. "Molygen Motor Protect: an antifriction and protective additive of the latest generation based on an organic compound with tungsten. It is optimal for the most modern vehicles using low-viscosity and low-ash oils. It deeply penetrates and forms a solid and heat-resistant layer in the metal through alloying with W ions. The latest formula provides maximum protection against thermal overload. The effect lasts for more than 50,000 km."
Or, for example, "Oil Additiv with molybdenum disulfide: a proprietary antifriction additive based on molybdenum disulfide. Thanks to the layered structure of MoS2, it significantly reduces friction between engine parts and strengthens their surfaces. Recommended for older generation vehicles (without particulate filters and catalysts)."
There are also smoke-reducing or stabilizing compositions. Such additives are designed to stabilize oil viscosity during heating, prevent pressure drop in the lubrication system, reduce oil consumption, smoke, engine noise, and inhibit the formation of carbon deposits in the combustion chamber.
Consequences of using additives
There are often reports that using additives for motor oil can have unpredictable consequences for engine operation. For example, it is said that the layer formed by additives on internal engine surfaces is difficult or almost impossible to remove.
Sometimes service technicians mention that components treated with certain additives cannot undergo grinding, honing, or other procedures. Generally speaking, negative consequences for the engine cannot be completely ruled out. However, it cannot be claimed that all these products are equally harmful.
Research results
How effective are motor oil additives and do they fulfill their primary task? The "Za Rulem" magazine provided a comprehensive answer to this question by testing five additives over a long period (120 engine hours, equivalent to a mileage of 10,000 kilometers under specified conditions) and obtaining quite interesting results.
Based on measurements, engine disassembly, analysis of engine parts, and oil condition, it was found that the additives had a positive effect on the working surfaces of friction units. For example, the height of microasperities and surface defects decreased, and the friction force was significantly reduced due to the antifriction layer. Consequently, mechanical losses and wear rates decreased, leading to lower fuel consumption and increased engine life.
Power in well-functioning engines increased by 1.3% to 4.0% depending on the additive manufacturer, primarily due to reduced mechanical losses and increased compression (on average by 0.2-0.3 bar) and torque improved at low and medium speeds. The promised fuel economy by additive manufacturers? Indeed, it exists. The highest effect, a reduction of more than 10%, was observed at idle or light loads.
Wear protection
The examination of the most important aspect yielded equally impressive results. Researchers note that engines treated with additives showed 12-60% less wear products compared to the reference control engine. However, each product had its own impact on the engine. For instance, Suprotec and XADO compositions had a better effect on the cylinders and piston rings, while Liqui Moly and Bardahl provided protection for the crankshaft bearings.
What about the oil?
Some might wonder if additives can harm the engine oil. Research has shown that the characteristics of lubricating compositions actually correspond to the parameters of normal aging oil.
What if the engine is faulty?
In automobile magazine they simulated engine wear by creating scratches on the bearing inserts and working surfaces of the piston rings, resulting in a sharp decrease in oil pressure, power loss, increased fuel consumption, and exhaust toxicity. Additives helped, especially those from Suprotec, Bardahl, and Liqui Moly. Specifically, oil pressure increased, and compression significantly rose by 1-1.5 bar!
To believe or not to believe?
As you can see, the action of at least some additives (and there is a wide variety of compositions available on the market) corresponds to the manufacturers' promises. Experts recommend using additives based on the condition of the engine. If the engine is new or not heavily worn, you can use additives from the group of geomodifiers. They are added once and provide a long-lasting effect.
In the case of a worn-out engine, stronger compositions should be used, which can help at this stage. They contain metallic additives and should be added with each oil change. By using them, you can achieve a certain, and possibly even a positive, effect, such as reduced oil consumption. However, it is unlikely that such therapy can be considered an alternative to a major engine overhaul.