Agree with most that if one changes oil frequently enough, any oil of the right viscosity will protect the engine. But for people like to read about oils, here is a new twist.

Saw the new Mobile 1 SL oil today at Wal-Mart and I was shocked.

Apparently Mobile decided to cheapen the formulation even further by using less and less PAO base stock in the SL formulation than the SJ formulation. Remember the original Mobile 1 was all PAO then to Tri-Synthetic, and now to another Tri-Synthetic. How do I know?

The new SL 5W-30 and 10W-30 oil's pour point increased more than 15 degrees. It was -65 deg (SJ) and now it is -49 deg (SL).

People all agree that the true synthetic base stocks like PAO has a very lower pour point. This increase in pour point indicated that the PAO content is lower in the new formulation.

BTW, the 0W-40 oil still has the same old -65 degree pour point and actually its kinematic viscosity at 100 degree Celsius has increased a bit for better high temperature protection. Also the Energy Saving rating has disappeared in the 0W-40 (according to the Mobile 1 Website as I cannot find a bottle for this). See it your self at

https://dallnd6.dal.mobil.com/GIS/MobilPDS.nsf/26b7c4b33367a4a086256665004e4266/9337c5cedcf5e32e852567b60056db77?OpenDocument

There are some errors in the viscosity section (more numbers than the column heading indicates).