Am citit pe un forum american. Este clar, ori era un insider ori un habarnist, alege tu. :twoup: Ceva timp in urma am pus si eu cateva intrebari indiscrete, uite raspunsul oficial: "Unfortunately, Castrol does not publish any of our formulations. Our additive systems and base oils are proprietary and chosen for performance and suitability first. Castrol uses only the highest quality materials, including synthetic base oils. Synthetic base fluid is manufactured chemically to possess superior viscosity characteristics at low temperatures, improved thermal and oxidative stability, and reduced volatility. Synthetic stock is created in a laboratory from small molecules which are reacted together to produce bigger "pure" molecules. As a result, the molecular structure of the lubricant can be precisely arranged to meet specific thermal or physical requirements and often exceed manufacturer's criteria for high performance engines. " We have developed and manufacture oils for a number of customers under their brand. The companies and the specifics of their oils is confidential information that we cannot share." Un lucru pe care il stiam destul de sigur mi s-a confirmat, uleiul 5w30 nu este sintetic ci este ulei grupa 3. :twoup: