I did some research over the internet about car oils in general and... :
The numbers preceding the "W" (W = Winter), mean low temperature fluidity. The lower the number, the lower the environment temperature may be, in which the oil can be used. Oils symbols 0W, 5W 10W guarantee easy starting and fast flow of lubricant to all points of the engine, even at very low temperatures.
The numbers that are after "-" means the viscosity at high temperatures. The higher the number, the higher may be environment temperature, at which the oil does not lose its lubricating properties. Oils of symbols 40, 50 and 60 ensure proper lubrication of the engine at higher temperatures.
Manufacturer require to determine the correct type of car oil. Much also depends on the condition of the engine. The new cars are usually applied synthetic oils (eg 5W-30) or semisynthetic (ie 10W-40). When buying a semi-synthetic oil, we offer quality similar to that of synthetic oils but at a lower price. In older vehicles, especially if the odometer shows more than about 100,000 kilometers, it is recommended to use mineral oil (eg 15W-50).
Engine oils contain special additive packages of cleaning the engine inside. Most supplements contain synthetic oils, which due to their viscosity grade form a thin lubricant film. The semi-synthetic oils additives is less, but they form a thicker film. Mineral oils, although it contains the least additives, form the thickest protective layer on the surface of lubricated components. Thus, if we replace the mineral oil synthetic oil, eg SAE 5W, can cause leaching of pollutants deposited in the engine, causing a leak. Pollution washed begin to circulate in the engine oil, causing clogging tubules, and decreased oil pressure. This could result in unnecessary oil spills and, consequently, the total corruption of the engine. Replacing or complementing the engine oil must therefore remember one very important principle: if we're not sure what drove our car before, you should never replace the mineral oil to synthetic. Synthetic oil can be replaced by a semi-synthetic or mineral, and semi-synthetic - a mineral.
Translated by google
D700 / RS200