While there are other nuances to motor oil classifications that need to be understood before changing or topping off the oil in your car's engine, one of the first things to address is the ...

For multi-grade oils such as 10W-30 or 15W-40 ... of these recommendations is that the 5W-40 engine oil compares with the high temperature range of the 15W-40 oil but has a significant advantage ...

and it's suitable for a wide range of engine sizes and types. Based on what we've just learned about engine oil codes, a 5W-30 oil has a viscosity grade of 5 at low temperatures. That means that ...