It must be remembered that each time you start the engine (not necessarily in the frost, and even at positive temperature) it takes some time to pump the oil has circulated for oil lubrication system, and it came to all the rubbing parts. At Vanessa Marcil you will find additional information. At this time the engine will just be run in both Oil-called "starvation" of which we have mentioned above. It is clear that this dramatically increases the friction and wear. Thus, more oil is able to maintain fluidity at low temperatures, the faster it will be pumped by the lubricating system and help protect the engine. The best in this regard are motor oils of OW.
Regarding the choice of the so-called "summer" class, it should be noted that the pain * Most European Car manufacturers recommend the use of oils of class "40" by SAE. This is due to high thermal stress of modern internal combustion engines and the presence of high temperatures, pressures and specific shear rates in different parts of the engine (piston rings, camshaft, crankshaft bearings, etc.). In these harsh conditions keep the viscosity of oil should be sufficient for the formation of an oil film and cooling of friction pairs. This task becomes especially urgent in order to prevent increased wear, scoring, and "jamming" in the summer or during a long stay in the "traffic jam" (in the absence of ventilation and cooling motor currents and counter-air, as a consequence, the oil temperature in the crankcase), as well as in the case of engine overheating due to potential malfunctions in the cooling system.