Hey guys, just wanted to throw my thoughts in here. I think we would all agree that there are engineering trade offs when choosing an engine oil. There is no question that heavier oils have advantages as do thinner ones. We also have to remember that car manufactures choose an oil that is adequate in a very broad range of temps. Case in point is GMs change from 10w30 to 5w30. I promise that guys in florida are not burning out starters, or suffering from excess cold startup wear from using 10w30 vs 5w30. If you were in Maine, the story could be different. I guess the question really is not what is adequate, but what is the best. If you live in a warm climate and use 5w30, are you better off than if you use a 10w30 or even a 15w40. I thik it mostly it has to do with driving habbits and conditions. Over the years, i have been bouncing around between thin and thick and kind of settled somewhere in the middle. I live in NC so weather is mild. My point to all of this really is that i dont think you can look at your oil cap and say whatever is printed on it is the best choice for me. Again, the auto manufacture did not put that there for you, it is there to be adequate for anyone that buys that car. I do have an issue with one thing that was originally posted.
"Your temps of 0 are not bad. Our cold start testing is to start after an overnight soak of -20F and immediately go to 5000 RPM to check the oil pressure control valve agianst overpressurization of the sytem... Test engines go thru hundreds of cycles of this without a lube problem."
For most of us, this is only about a years worth of use.