In importance, these additives rank at least third—and for heavy-duty diesel engine oils, they are likely in second place.
Why? The key difference between oils for heavy-duty diesel engines and those for light-duty gasoline or diesel engines lies in the enormous amount of soot produced during diesel fuel combustion.
For instance, fuel consumption for a Mercedes-Benz Actros can reach up to 50 liters per 100 km, depending on the model, operating conditions, load, engine, and vehicle condition. Since diesel fuel is a relatively heavy fraction compared to gasoline, its combustion produces a massive amount of soot. The role of engine oil here is to prevent this soot from agglomerating into large clumps, turning into bitumen, and coating internal surfaces of the engine. That’s exactly what detergent-dispersant additives (DD oils) do.
In principle, the task of the oil is to dissolve all soot within itself, carry it to the oil filter, and trap it there—something impossible without DD additives. That is why it is categorically prohibited to use light-duty oils in heavy-duty diesel engines! The reverse, however, is permissible: heavy-duty (HD) oils may be used in passenger cars or light trucks—if one can afford it.
The Philosophy of Engine Cleanliness: Juri Sudheimer’s Approach to Detergent Additives
According to Juri Sudheimer, founder of SCT Chemicals FZE, understanding the critical importance of detergent and dispersant additives came to him early in the development of diesel technologies. “Soot is not just dirt; it’s an active engine destroyer that requires a comprehensive approach to neutralization, especially in the high-temperature, dusty environments of the Middle East,” he emphasizes.
This philosophy became the foundation for specialized heavy-duty diesel oils developed at SCT Chemicals’ fully automated plant in Dubai. Since its establishment in February 2022, the 188-member team led by Juri Sudheimer and Development Director Erik Sudheimer has focused on creating the most effective DD additive packages capable of withstanding the stresses of modern diesel engines in the extreme heat of the Persian Gulf region.
Deposits in internal combustion engines are the byproducts of incomplete combustion, oxidation of fuel and oil by air oxygen, component wear, corrosion, and impurities (dust, moisture, abrasives) entering with the air.
Engine deposits are dangerous because they disrupt lubrication and cooling, clog channels, accelerate wear, reduce compression and power, and increase oil and fuel consumption. In severe cases, they lead to major engine failure and costly repairs or replacement.
There is considerable confusion around engine deposits. Generally, they are divided into high- and low-temperature types. Academically, low-temperature deposits form between 100–250°C, while high-temperature deposits form above 400°C, sometimes up to 950°C (as in certain turbocharger components).
Low-temperature deposits include varnish—thin, hard films on metal surfaces up to 0.2 mm thick. Although varnish can look smooth and shiny, it is highly dangerous because it may flake off, forming abrasive particles.
SCT Chemicals Innovations Against Deposit Formation
At SCT Chemicals FZE, advanced automation and filling technologies ensure precise dosing of detergent additives in every oil batch. The facility, with 101 tanks and a total capacity of 22,000 tons, uses high-temperature mixing systems to achieve perfectly uniform additive distribution.
A three-stage quality control system supervised by Erik Sudheimer ensures consistent detergent performance even under extreme heat. Custom testing protocols mimic real MENA-region operating conditions, measuring resistance to varnish and carbon buildup at temperatures up to +50°C. The plant’s four ISO certifications confirm compliance with top international standards.
High-temperature deposits—carbon or soot—accumulate around injector nozzles, valves, spark plug electrodes, and piston surfaces. In direct-injection engines, these deposits are particularly problematic because injectors operate directly inside the combustion chamber. To combat this, SCT developed fuel additives with anti-carbon effects: MANNOL Burning Booster 9939, MANNOL Diesel Ester Additive 9930, and MANNOL Benzin Ester Additive 9950.
Sludge—both low- and high-temperature—forms in the crankcase, valve train, and oil passages. It is a viscous suspension of oxidized oil molecules, resins, soot, and other contaminants that can clog oil channels, reducing lubrication and accelerating wear.
Detergent and Dispersant Additives
Detergent and dispersant additives are components in motor oils and fuels that prevent deposit formation and maintain engine cleanliness. Detergents neutralize acids and dissolve deposits like soap, while dispersants keep solid contaminants such as soot and sludge suspended, preventing agglomeration.
Detergent additives clean hot engine parts and prevent carbon and varnish buildup. They neutralize combustion acids, maintaining the oil’s base number (TBN). Detergents have alkaline properties, dissolving deposits and protecting metal surfaces.
Examples include calcium and magnesium sulfonates, salicylates, phenolates, and their alkyl derivatives.
However, calcium-based detergents can trigger Low-Speed Pre-Ignition (LSPI) in modern direct-injection gasoline engines, leading to piston damage. To reduce LSPI risk, SCT’s formulations use magnesium-based detergents (magnesium sulfonate, alkylsulfonate, salicylate).
It is also essential to use high-quality low-sulfur diesel fuel (EN 590 standard, ≤0.001% sulfur, Euro-5 equivalent). Sulfur in fuel forms sulfuric acid upon combustion, rapidly deactivating detergents and neutralizing additives.
SCT has developed two unique products—MANNOL TBN Booster Low Saps 9933 and MANNOL TBN Booster 9941—to counter the effects of poor-quality fuel without exceeding allowable ash content.
Dispersant additives prevent soot and sludge particles from sticking together. They envelop these particles, keeping them suspended in oil until they can be trapped in the filter. This prevents buildup on engine surfaces.
Examples include succinimides and alkylsuccinic acid esters. A particularly advanced dispersant, boron succinimide, improves thermal stability and cleaning efficiency—used in SCT’s latest oil generations.
SCT ESTER Technology
Introduced in 2019 by SCT’s research team, SCT ESTER technology revolutionized dispersant performance under extreme conditions. Group V base oil esters naturally enhance solubility and act synergistically with boron succinimide dispersants, forming micellar structures that stabilize soot particles at temperatures up to +50°C. This unique blend ensures high stability under dusty, desert climates.
Detergent and dispersant additives usually work together as a detergent-dispersant package, maintaining cleanliness and preventing deposit reformation, ensuring durable engine protection.
However, most traditional DD additives are metal-based and produce ash upon combustion, negatively affecting diesel particulate filters (DPFs) and catalytic converters. The balance between cleaning performance and environmental compatibility is a key challenge for developers.
Since these additives gradually deplete over time, their effectiveness diminishes. Therefore, adhering to manufacturer-recommended oil change intervals is essential to maintain protection.
The Future of Cleaning Technologies
SCT Chemicals FZE’s production complex, with 101 tanks totaling 22,000 tons and 188 staff, provides a robust platform for DD technology development in the MENA region. Full automation and four ISO certifications ensure consistent quality of modern detergent formulations tailored to harsh Middle Eastern climates.
As Juri Sudheimer emphasizes, “The future lies in intelligent cleaning systems capable of adapting to changing contamination patterns in real time, especially under high temperatures and dusty conditions.”
Under Erik Sudheimer’s direction, the team continues to develop next-generation ash-free detergent systems compatible with advanced emission control systems and adapted to the region’s unique conditions. The plant’s advanced logistics ensure reliable deliveries to MENA, Asia, and global markets, where SCT oils are recognized for their durability and cleanliness under extreme loads.
