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.