Understanding Oil Viscosity Leads to Better Engine Performance
The viscosity of the oil is critical in how well it flows through your engine and gets to the critical components. Viscosity, in the very simplest of terms, is the measure of how a liquid resists to flow.
For example, water has a much lower viscosity than molasses. Obviously, if you pour a bottle of water, the water will come out way quicker than if you dumped out a bottle of molasses.
Animation courtesy of the TeachEngineering YouTube Channel
Having an oil with the right viscosity will give your engine the best protection. Knowing the correct viscosity oil for your vehicle maximizes both protection and performance. An easy way to make sure you’re getting the right oil for your vehicle is to use an oil change kit from Power Oil Center. Not only will it include engine oil specific for your car or truck, but you’ll also get a premium oil filter, a crush washer and a funnel. Our experts have done the research to find the best oils…and the right oil… for your vehicle.
The viscosity grade of oil is set by the Society of Automotive Engineers (SAE). Engine oils will show two numbers. The low-temperature viscosity is the winter grade and is the “xW” at the beginning of the sequence. The second number correlates to the high-temperature viscosity – the -30, for example in a 5W-30 grade.
Measurement of the low-temperature viscosity is done through a Cold Crank Simulator Test. This determines the oil’s low-temperature dynamic viscosity. Dynamic Viscosity is how much force is needed to move an object (such as a piston rod) through the fluid.
An engine has a lot of moving parts. The most critical moment is at startup when the engine is cold and oil must get to critical engine parts rapidly. A 5W-30 or 0W-30 oil will be more effective in cold temperatures than a 20W-40. It is why the “W” is placed here in the description. In fact, the “W” stands for winter.
The second part of the SAE viscosity grade is the high-temperature viscosity, also known as kinematic viscosity. For example, a 10W-40 grade oil will provide lubrication and protection at high temperatures than a 10W-30.
The higher the second number, the more suitable it is for use in high temperatures. As temperatures rise, an engine oil with a higher kinematic viscosity is a better choice. When determining which grade of oil to use, refer to your vehicle’s owner manual.
Why Viscosity Matters
Viscosity helps determine how well the oil will protect your engine by lubricating, cooling and cleaning.
In cold temperatures, oil with too high of a viscosity can thicken and it’s harder to get it to circulate through the engine. Those in cold climates know that it is sometimes difficult to start a car when temperatures drop.
Using oil with too high of a viscosity will increase the wear on engine parts leading to breakdown. In worse-case scenarios, your engine can be damaged by using the wrong viscosity oil.
Likewise, in the hotter weather, oil with a low viscosity may run too thin and won’t provide the lubrication and cooling required.
Using oil with the wrong viscosity can also lower fuel economy and lead to higher wear on engine parts. Fortunately, you can find all types of oil on Power Oil Center, including Factory Racing Parts, Red Line, Craftsman, PennGrade 1 and Royal Purple.