Wo we have gone from 10W-40, to 10W-30, to 5W-30, to 5W-20, to 0W-20. Next it will be 0W-16. Have engines changed all that much? Has oil changed all that much? Or is it still pretty much the same; just a different mindset based upon the oil industry propaganda? Are we now using lighter weight oil; just because they are telling us to use lighter weight oil?