what is the meaning of 10w30 engine oil
Motor oil The Society of Automotive Engineers (SAE) has established a numerical code system for grading motor oils according to their viscosity characteristics. The original viscosity grades were all mono-grades, e.g. a typical engine oil was a SAE 30. This is because as all oils thin when heated, so to get the right film thickness at operating temperatures oil manufacturers needed to start with a thick oil. This meant that in cold weather it would be difficult to start the engine as the oil was too thick to crank. However, oil additive technology was introduced that allowed oils to thin more slowly (i.e. to retain a higher viscosity index); this allowed selection of a thinner oil to start with, e.g. "SAE 15W-30", a product that acts like an SAE 15 at cold temperatures (15W for winter) and like an SAE 30 at 100Â°C.
Price of oil From 1999 til mid 2008, the price of oil rose significantly. It was explained by the rising oil demand in countries like China and India.[7] In the middle of the financial crisis of 2007–2008, the price of oil underwent a significant decrease after the record peak of US$147.27 it reached on July 11, 2008. On December 23, 2008, WTI crude oil spot price fell to US$30.28 a barrel, the lowest since the financial crisis of 2007–2010 began. The price sharply rebounded after the crisis and rose to US$82 a barrel in 2009.[8] In July 2008 oil reached a record peak of US$147.27 but by February 2009 it sank beneath $40 a barrel.[9] On 31 January 2011, the Brent price hit $100 a barrel for the first time since October 2008, on concerns about the political unrest in Egypt.[10] For about three and half years the price largely remained in the $90–$120 range. In the middle of 2014, price started declining due to a significant increase in oil production in USA, and declining demand in the emerging countries.[11] The oil glut—caused by multiple factors—spurred a sharp downward spiral in the price of oil that continued through February 2016.[12] By February 3, 2016 oil was below $30—[13] a drop of "almost 75 percent since mid-2014 as competing producers pumped 1–2 million barrels of crude daily exceeding demand, just as China's economy hit lowest growth in a generation."[14] Some analysts speculate that it may continue to drop further, perhaps as low as $18[15]