When someone refers to viscosity, they are usually talking about the oil’s resistance to flow. Viscosity might also be referred to as the oil’s thickness. For example, water has a low viscosity. In contrast, honey has a very high viscosity. Slower than molasses in January! The unit used to express viscosity in oil is measured in centistokes.
How is Viscosity Measured?
Oil viscosity is measured in centistoles at both 0ºF and a 212ºF (the respective freezing and boiling points of water at sea level) to determine how resistant to flow oil is at each temperature. The number before the W in the oil rating indicates the viscosity during the winter (cold) months and the second number indicates the viscosity during the summer (warm) months. For example, motor oil rated as 10W-30 has less viscosity when it’s cold. Additionally, 10W-30 has less viscosity than an oil rated as 20W-50.
The Viscosity Index
Motor engine oil has to be able to maintain its ability to lubricate the engine, no matter the temperature. When the weather cools, the oil needs to flow easily enough to circulate throughout the engine. Too much resistance and the engine is harder to start, reducing fuel economy. Not enough resistance, though, and the oil won’t effectively lubricate parts of the engine, like bearings and cylinders.
4 Additives that Help Maintain Viscosity
In order to keep your engine properly lubricated, consistent viscosity needs to be maintained at all temperatures. To do that, motor oil manufacturers use a number of different additives, including:
Viscosity improvers. These additives make your engine oil more resistant to thinning as the temperature climbs.
Detergents. These additives keep the surfaces of your engine clean so oil is freer to move between the parts of your engine.
Friction modifiers. These additives reduce the amount of friction in your engine, effectively keeping your oil from shearing, or losing viscosity.
Antioxidants. These additives reduce the thickening of the oil, increasing fuel economy.
If you are interested in learning more about what additives will help your engine maintain its viscosity, especially during these cold weather months, check the label on the particular oil bottle that you want!
Come in and See Us!
Check your owner’s manual to see what type of oil and rating your manufacturer recommends. If you want an expert to change your oil, bring your car into Quanz Advanced Auto Body. We can recommend the right type of oil for your car for cold weather and, in a few months, get you prepared for the warm weather. Stop in today–no appointment necessary!