I just did an oil change today and had to run out to Wal-Mart and pick up a few quarts of oil.

I bought the current Mobil 1 10w-30 fully synthetic and noticed that the ILSAC rating is now GF-4 (previously GF-3).

The API rating is SM, which as I understand it is a "step above" the SL rating required for the EVO.

Can I also assume that the GF-4 rating is a step above the GF-3 rating?

I'm just curious about how these ratings work.


Cabo