10w30 vs 10w40 – Differences in Engine Oil Viscosity
The difference between 10w30 and 10w40 is the thickness of the oil at operating/high temperatures, at which 10w40 is thicker than 10w30. In This Guide When to Use 10w30 vs 10w40 High Mileage Vehicles How Oil is Graded Single Grade Oil The first viscosity number, “10” in the case of both of these oils, rates how easy it pours at starting/low temperatures, such as starting the engine during winter. The lower this number is, the easier it pours when cold, so an oil rated “5” will pour faster than one rated “10.” The second number, “30” and “40” for these … Read more