An engine’s reliability and performance are closely linked to the quality of the lubricant working within it. This is particularly true when the engine operates for extended periods at full throttle and full load, which also affects fuel consumption
The primary function of a lubricant operating inside an engine is to keep the surfaces of interacting mechanical components separated from each other. Two examples are the pistons sliding inside the cylinders and the plain bearings that support the crankshaft. In both cases, the oil must create an extremely thin film that prevents direct contact between metal surfaces, even though they are heavily pressed together by the succession of operating cycles and in proportion to the loads involved. These forces are particularly high in earthmoving and agricultural machinery.
The ability to withstand them properly is greatly influenced by the viscosity of the lubricants, a parameter that changes with temperature and that, until recently, the higher it was, the better it protected the engine—albeit at the expense of efficiency. High viscosity, in fact, leads to energy losses that negatively affect performance and fuel consumption. It is therefore essential to find the right balance between reducing friction and protecting the engine, an equilibrium that becomes increasingly difficult to achieve as operating temperatures and stresses rise.
To measure these effects, engineers developed the “Ht-Hs” (High Temperature High Shear) parameter, which defines the viscosity of a lubricant when operating at high temperatures and under severe mechanical stress. Under such conditions, the viscosity value indicated by the SAE classification at 100 degrees Celsius is not sufficient.
For engine oils intended for heavy-duty vehicles, the Ht-Hs parameter—measured at 150 degrees Celsius—has therefore been introduced. This threshold, combined with measurements taken under high stress, accurately determines a lubricant’s ability to reduce fuel consumption without compromising engine protection.
Typically, a lubricant with an Ht-Hs value lower than 3.5 centipoise—the unit used to measure viscosity—allows the engine to operate with lower internal resistance and therefore reduced fuel consumption. However, not all engines are compatible with such values, so the use of low Ht-Hs lubricants must be approved by vehicle manufacturers.
In this regard, the European Automobile Manufacturers’ Association (Acea) introduced in 2024 a specific technical specification called “Acea F01,” which identifies oils with Ht-Hs values between 2.9 and 3.2 centipoise. This standard defines low-viscosity, fuel-economy lubricants that, in engines designed to use this specification, ensure both maximum protection and minimal consumption, as well as compatibility with the latest exhaust after-treatment technologies.
Examples of latest-generation lubricants specifically designed for heavy-duty machinery include those from the Pakelo “Goldenstar F-La Plus Sae 5W-20” and “Goldenstar F-La Plus Sae 5W-30” lines, which meet the requirements of engines calling for Acea F01 and Low SAPS technologies, ensuring low levels of sulphated ash, phosphorus, and sulfur.
Also available are the “Goldenstar La Plus Sae 10W-40” and “Goldenstar La Plus Sae 5W-30” oils, approved by major manufacturers and suitable for all engine lubrication and protection needs. Thanks to their wide range of specifications, they are particularly suitable for mixed fleets or multi-brand workshops. In addition to these “Excellence” products, the Pakelo range is completed by the “Premium” and “Regular” lines, covering all lubrication requirements.
Title: Lubricant Pakelo: conciliatory balancing acts
Translation with ChatGPT
