What Do The Numbers Mean On A Bottle Of Oil?

Do you know what the numbers mean on a bottle of oil? Do you find it confusing looking at bottles of oil and deciding which oil should be used in your vehicle? Oil has an important part to play in the life of your vehicle engine. Without it, an engine may ‘seize’ which means its reciprocating and rotating components fail to do what they should be doing. An engine running out of oil completely is a very rare occurrence although not unheard of and can be caused by extreme neglect or a leak caused by a hole in the oil pan or a loose oil drain plug. The type of oil you use in your vehicle is linked to the manufacturer’s recommendations, the climate and the type of driving you do. K&M Tyres looks at what the numbers mean on a bottle of oil and why they are so important.

The numbers refer to oil ‘weight’

The numbers on a bottle of oil refer to the oil ‘weight’. However, that term is somewhat misleading, as they do not relate to how heavy the oil is, but rather its viscosity. This is the thickness of the oil and a reference to how easily the oil pours at a specified temperature. Thin oils with their lower viscosity pour more easily at low temperatures than thicker oils with a higher viscosity. If you consider other liquids, it becomes clear that water has a low viscosity and syrup has a high viscosity. Take the scenario of honey, which flows much better when it is heated. In short, it can be said that the higher the number on the bottle, the thicker the oil.

How the oil flows when it is cold and at a normal engine operating temperature

On a bottle of oil there are two numbers with the first number preceding the letter ’W’ which stands for ‘Winter’. This measurement relates to how the oil flows when it is cold, for example, when the engine starts. The second number relates to how the oil flows at normal engine operating temperatures. As stated previously, smaller numbers flow more easily. Cold ‘Winter’ ratings run from 0W through 5W, 10W, 15W, 20W to 25W. Hot ratings are from 20 through 30, 40, 50 to 60.

How can K&M Tyres help you determine which is the right engine oil for your vehicle?

It is important to find the right engine oil for you car. K&M Tyres is a Castrol Service Centre and we know the oil that is right for your vehicle. We stock Castrol Edge, Castrol Magnatec and Castrol GTX oils. Call us on 01892 653131 to book your vehicle in for an oil change. All in all, it could help you save on expensive repairs and will save you lots of time and money in the long run.