It is the resistance of the fluid (in the specific case of the oil) to the flow.
One example is the flow of a lubricant at extreme temperatures.
High viscosity, slow flow (viscous oil). Low viscosity, fast flow (thin oil).

Mineral oil is a mixture of basic lubricant at least 85% and various types of additives depending on the type of lubricant. When referring to mineral oil, it is essentially a refining of crude oil,treatment in which all chemicals are not removed with negative effects on the durability and persistence of viscosity,

It is the blend of high purity essential lubricants they have produced by chemical purification processes but also by isolation of fractions (polymerization), with specific types of additives. Synthetic lubricants (full synthetic) are the result of chemical treatment. Their behavior is more qualitative, since they have excellent physical properties while they are selected more and more for modern engines despite their high cost

It is an intermediate grade of lubricants made from basic lubricants that we use to produce mineral oils but also synthetic and additives for the production of an intermediate grade lubricant which is usually composed at a rate of 20% -80% based on mineral oil and synthetic respectively.

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We do not know the cause, but it is a fact that this indicator is quite "misunderstood". Most car owners think it refers to the environmental temperature in which they are the vehicle is running. Certainly this is not the case. in the form of eg (10W-40). But what does this index mean? Let's clarify its meaning with the example of a lubricant having a viscosity index of 10W-40. Initially, the word "W" comes from the word Winter and accompanies the first number we find on the index, which expresses the dynamic viscosity of the lubricant at a very low temperature. The second number (in our example is "40")expresses the kinematic viscosity recorded at high temperature. So how do we choose the right lubricant before scheduled maintenance? The answer is simple. Refer to the "user manual" and observe the recommended viscosity index for our vehicle engine. Beyond the choice is straightforward since each oil package indicating the corresponding viscosity index.

Modern motors operate with a thin lubricant, so the recommended values from the manufacturer are usually lubricant specifications: There is a "confidence vote" from the manufacturer.

Having now reached the Full Synthetic-Semi Synthetic-Mineral type, but also the appropriate index viscosity according to what we have just mentioned, the last point before the final lubricant selection is the certification it carries. In the past, the lubricity specifications were only available from institutes such as the European Association of Manufacturers (ACEA) and the American Institute of Petroleum (API). Today, however, car manufacturers have created their own OEMs for each engine separately. Thus, referring to your vehicle's "user manual", you can locate the oil specifications required by the manufacturer and choose a market lubricant that meets them. By observing the labels on the back of a lubricant package, you will find the code names that indicate which companies approve the use of the product in question, and 0W-30, 5W-30, 10W-40 or some other similar price.

- Follow manufacturer's instructions for oil selection.
Refer to the manufacturer's book accompanying each car.

- Change the oil at the intervals specified by the lubricant manufacturer. Many delegations are pushing for more frequent change in order to increase their turnover.

- Do research market for the cost of lubricants. In many garages of official networks the oil change charges are particularly high and are usually not justified by the quality of the lubricants.    In a small German medium they charge 120 euros - not gold was the oil.

- Watch the variation in fuel consumption depending on the type of oil and the engine condition. So they will find the best combination for economical driving.

• - Approximately 30 seconds are required to "release" the oil to all parts of the engine once it is activated.
• - The viscosity indication S.A.E (Compound Automobile Engineering) to form 10W-40, the numbers are not reported at operating temperatures such as mistakenly believe them.
• - We always select a lubricant that meets the specifications we will find in our vehicle's "Owner's Manual".
• - The low lubricant consumption of the engine is justified, as you will see in the manufacturer's manual. On the contrary, when it's increased, the engine needs repair!
• - Choosing the right lubricant and replacing it regularly spark the longevity of the engine.

The right choice of lubricant, combined with its replacement in the Intervals proposed by the manufacturer are the most important factor for the trouble-free operation of our engine.
Have you chosen the right kind of lubricant?
Have you selected the appropriate viscosity index?
Is the product certified with the appropriate specifications?
If you responded positively to all three questions, you have made the right choice! Remember also that it is it is important to replace the lubricant once the required mileage (usually 10,000 km) or at least once a year, and you've taken the first step for longevity and trouble-free engine operation. Do not forget, moreover, that the lubricant is for the engines that blood to the human body!