after reading several articles by the automobile experts online, what i have learned and concluded regarding engine oil is...
1. Engine oil viscosity or lubrication is shown by 2 numbers. The first number indicates the thickness or viscosity of engine oil at cold engine. And the second number indicates the viscosity at optimal engine temperature.
2. The higher the number , more viscous the engine oil and more is the lubrication efficiency.
3. It is important to understand that the most of the automobile companies take the optimal temperature of the engine at 2 extremeties. 0c or 32f is the temperature taken by most of the companies when the engine is cold. And 37c or 100f is the temperature of the engine when it is running for some time and considered hot.
4. Now taking our climatic conditions, 0c for the cold engine is never the temperature in our atmosphere in the morning. Normally its around 25c. And 37c is again not the temperature of the engine when it is running for almost an hour in 45c. Even i have travelled at 51c during summer on highways.
5. 0w 20 oil has minimal viscosity and is best suitable for hybrid cars running in cold environment where temperature rarely reaches 35c. As the climate temperature rises, so does the engine temperature. At higher temperatures the oil becomes less viscous and less lubricant. According to many experts it may even become watery in consistency. This may eventually cause the engine to loosen up in the long run if engine oil with very low viscosity is used at high temperatures.
6. However in hybrid cars , most of the experts recommend to opt for 10w 30 only in the countries where weather is not much cold, and the extreme hot climatic conditions can turn your low viscosity engine oil to water. 10w 30 is only one step up in viscosity as compared to 0w 20 but it will be protective enough for engine, maintaining enough lubrication even when temperature rises to 50c.
7. I hope everyone has a clearer picture now.(h) ofcourse everyone still has the right to choose. and i hope it helps....(a)