Which Is Thicker 15W40 Or 5W40 – Understanding Viscosity For Optimal
Navigating engine oil choices can be confusing, but understanding viscosity is key to protecting your engine. While both 15W-40 and 5W-40 offer excellent protection at operating temperature, their “W” ratings indicate significant differences in cold-start performance, with 5W-40 being the thinner, more free-flowing option when the engine is cold, and therefore often preferred for modern…