Originally Posted by SR5
However the Castrol Edge 5W30 in Australia is a Euro A3/B4 oil with a higher HTHS (> 3.5 cP) and it's "only" API SL (not SN) which means it doesn't have a limit placed on it's ZDDP level. I hear it has about 1000 ppm Zinc. It's still passes all the API SN quality tests, it's just is above the chemical limit. This SN Vs SL ZDDP limit only applies to 30 grades and below, so not 40 grade oils.
This is all very important to note, especially when looking back at the original 10w-30 recommendation, where it would be a 10w-30 conventional ILSAC meeting the basic spec, versus a 5w-30 A3/B4 one might find now.