How Motor Oil is Made — Part 4: The Additive Package
The base oil is the foundation. But the other 5–30% of what’s in your oil — the additive package — is what separates a motor oil that just meets spec from one that actually protects your engine. Here’s how detergents, dispersants, ZDDP, antioxidants, and VI improvers work — and why two oils on the same base stock can perform completely differently.