Jul 31, 2017 Please note that vehicle requirements may vary so consult your car's handbook for the correct viscosity grade. SAE_Viscocity.png. Share me. Oil Engine oil viscosity refers to how easily oil pours at a specified temperature. oil with a 5W-30 grade thickens less than oil with a 10W-30 grade in cold weather. May 28, 2018 Dynamic viscosity is measured using the Cold Crank Simulator test, and is used to determine an oil's low-temperature viscosity grade. This would Nov 2, 2017 Just be sure to consult your manual, and choose the oil grade that matches how you drive for the best possible engine protection. Check out all Feb 21, 2019 These figures represent the engine oil's viscosity grade, which is the lubricant's level of fluidity and efficiency at low and high temperatures.
The 40 in a 10w-40 simply means that the oil must fall within certain viscosity limits at 100 degC. This is a fixed limit and all oils that end in 40 must achieve these limits. Once again the lower the number the thinner the oil, a 30 oil is thinner than a 40 oil at 100 degC etc. Oil weight is a term used to describe the viscosity of an oil, which means how well it flows at a specific temperature. The Society of Automotive Engineers (SAE) assigns a viscosity number, or weight, to oil based on its flow at 210 degrees F, which is roughly the standard operating temperature for most motors. The viscosity index can be calculated using the following formula:  = − − where U is the oil's kinematic viscosity at 40 °C (104 °F), and L and H are values based on the oil's kinematic viscosity at 100 °C (212 °F). The service rating of passenger car and commercial automotive motor oils is classified by the American Petroleum Institute (API). The program certifies that engine oil meets certain Original Equipment Manufacturer (OEM) quality and performance standards.
A 30 grade oil, thick enough to protect in the heat, was recommended for summer use. Then, multi-grade oils were formulated. A 10W-30 had the winter cold start Nov 7, 2018 A single grade oil does not contain viscosity modifier or polymeric viscosity index improver. The SAE classification (SAE J300) has proven 11