Motor oil: how do I choose it?

All motor oil manufacturers sing the praises of their products in rare words, and all oils are "the best oil" you can buy. But How do I distinguish between oils? Well, there are a few criteria to separate the oils that can be checked just by looking at the label on the container.

To start with, we have the SAE (Society of Automotive Engineers), and represents the fluidity or viscosity of the oil at certain temperatures. Low viscosity numbers mean the oil flows well at low temperatures, and a high viscosity number means the engine runs well at operating temperature. Multi-viscosity or multi-grade oils are designed to protect the engine well in a wide range of temperatures.

We continue with what is called API (American Petroleum Institute). It consists of two letters, the first of which determines the engine type for which the oil has been designed, and the second letter represents the API quality level. Thus, if we have an engine that requires an API SB, the API SG and SH will also work, what we cannot do is the opposite, if our engine requires a higher API of the oil that we use. The letter S at the beginning refers to gasoline engines, while the C assigns oils for Diesel engines.

Normally, the viscosity grade of oils is represented as “5W-50”, for example. In this case it represents a multigrade oil, which works well at different temperatures. The initial 5 represents up to which starting temperature it protects well, in this case 5 is a very good figure, and it protects well down to -25ºC. If it were a 20, it would protect well down to -9ºC. On the contrary, the 50 represents its protection at high service temperatures, and again the 50 is a good figure, almost the maximum that is found except in some very particular motorcycle oil.

For the use of Spain, with a 20w-50 it is enoughNow, to be exquisite, the 5w-50 that Mobil offers seems unbeatable to me, better if possible than the 0w-40 of the same brand, at least for our market.