Oil Viscosity: What do Those Numbers Mean?

Oil is an essential part of your car. It allows metal parts of the engine to move with minimal wear. To do that, it has to be thick enough to coat the parts but thin enough to move through the engine. That thickness, or resistance to flowing, is called viscosity. Viscosity is measured by how well oil flows at a set temperature and is graded from 0 to 50. Viscosity changes with temperature, getting thicker as it gets colder. A 5 weight oil works best at low temperatures. A 50 weight oil works best higher temperatures.

Because the temperatures in an engine can vary greatly, engine oil is generally multi-grade, meaning the viscosity can adjust with the temperature. Additives allow the oil to get thicker as it gets warmer. A 10W40 oil can work well at low and high temperatures. The "W" stands for winter grade. Here in Lakewood, CO, our car repair and maintenance professionals are happy to answer your questions about oil and other automotive issues.

Categories: Service