Oils and Viscosity

October 9, 2017 @ 5:45 pm
Oil Viscosity

Oils and Viscosity

When it comes to choosing the right oil for your car, we already talked about the important facts you should look when you pick it, now we are going to go deeply in the importance of the numbers in the bottles and what they mean. We have mentioned that this letters and numbers indicate the viscosity levels, but what does it really means?


It is a property of the liquids, in this propper case, it is the oil’s resistance to flow and shear. Water, for example, has a very very low viscosity, flowing faster. The oils, on the other hand, are high viscosity fluids, nevertheless, as you increase the temperature the viscosity levels lower and they flow faster and easier. For lubricant oils, the viscosity grade is determined by the Society of Automotive Engineers (SAE) and they developed a scale and standars of measurement and this is how oils are classified. Lubricants are also divided in multigrade and monograde oils, multigrade means the oil fulfills two different viscosity specifications (two numbers) for different temperatures while monograde oils only respond to one specification. Currently, almost all of the engine oils you find are multigrade.

Importance of Viscosity

This property determines how the oil is going to reach all the components in your engine, how it will pass through the filter and how it will drain back. When it is cold, it flows slow and thick and it will cause damage to your engine. In the other hand, the lower viscosity, the easier it will go through the engine. In summary, the lower temperature, the highest viscosity and the higher temperature means the lowest viscosity. This is why many people prefer the multigrade oils, because they provide protection to the engine in different grades of temperature.

Multigrade Oil

This type of lubricant oil has its importance in the capacity of modifying the viscosity according to the temperature conditions. In the label of a multigrade oil you will find two numbers as we already said, the first one followed by a “W” and it the viscosity of the oil in winter or cold temperature, and the second number indicates the viscosity of the oil under normal engine temperature. This is what protects the engine from the damage caused whe you start your car and it is cold.

Remember you must always guide from the manual and follow what it says according to your car and how you use it. Choosing the right oil is very important to  care for your engine and you should keep changing it and the filter every so often.