What does the weight mean on a can of motor oil?
Lets me start off by saying that oil is not measured by weight it is measured by viscosity. The first number on a bottle with the w behind it stands for winter. That is what the w stands for on a bottle of oil ( WINTER ) not weight. The lower the first number on the bottle is the viscosity of the oil in cold weather starts and heps the engine crank easier.
On every bottle of motor oil there is a seal that gives you three pieces of information: • The API service rating • The viscosity grade • “Energy Conserving” indicator (it either is or it isn’t) The API service rating is a two-letter rating that tells you the type of engine the oil is meant for (gasoline or diesel) and the quality level. The viscosity grade (for example, 5W-30) tells you the oil’s thickness, or viscosity. A thin oil has a lower number and flows more easily, while thick oils have a higher number and are more resistant to flow. Water has a very low viscosity — it is thin and flows easily. Honey has a very high viscosity — it is thick and gooey. Go to the next page to learn how viscosity is measured.
