Originally Posted by spect2k
Do you think it is really the best idea to start changing oil grades? If you don't like Mobil1 5w-30, then you switch to mobil1 0w-40 because it's a better formula? What about a different brand 5w-30? From all of the articles I have read where the experts are speaking about oil, I can't recall a single one that doesn't practically have in bold letter, "Always use the factory recommended weight oil". Unless the car is being modified or something, I have enough faith in the engineers that they chose the appropriate weight oil for the car ahead of time regardless of warmer temps (TX, FL, AZ) or colder temps (MN, AK, ME).
Those same engineers didn't build an engine that'll run forever, so why trust their oil judgement?
In all seriousness, the factory recommended oil weight is not 5w30. It's a range based upon the ambient temperatures you operate in. 5w30 just happens to fit within the range most people use.
On the same note: if you are tracking the car, you should probably run 15w50. If you are operating in the arctic, 0w30 at the heaviest. If you like to drive your car hard, often, a 0w40 or 5w40 would probably be a good bet.
The engineer/owners manual creators try to pick a one-size-fits-all....but with some knowledge, you can pick a one-size-fits-you