Understanding Oil Specifications — What They Really Mean
When it comes to engine protection, oil specifications matter just as much as the oil itself. From API and ACEA to ILSAC and OEM-specific ratings, these classifications aren't just technical jargon—they define how well your oil performs under pressure. Whether you're running a high-mileage work truck, a performance car, or heavy-duty equipment, understanding these specs can mean the difference between long-term reliability and premature wear. On this page, Vyscocity breaks down what each spec means, why it matters, and how to choose the right oil with confidence.
OEM Oil Specifications
A performance specification used in many Chrysler, Dodge, Jeep, and RAM vehicles. It focuses on deposit control, wear resistance, and oil stability under heat and load. Oils meeting MS-A0921 are often synthetic and designed for extended oil change intervals.
GM dexos R – Required for newer GM engines; emphasizes oxidation resistance and deposit control. AMSOIL Signature Series is fully dexos R-compliant.
