My last exposure to Castrol was in the early 2000s and the "German Castrol" we all knew and loved. Outside of boutiques and VRP (which I'm currently using for some clean up that may or may not be necessary), it seems M1 ESP 0W-30 is the current darling for punching above its class, great value readily available at Walmart, and using a higher concentration of PAO/Esters. In checking the approvals for ESP I noticed it seems to be almost identical to the Castrol Edge Euro A3/B4 family in that regard, but otherwise I'm not finding much current information on it's base oil composition and additive package. Well, more accurately, the 5W-30 flavor has the following approvals:
- ACEA A3/B4
- API SL
- BMW Longlife-01
- MB-Approval 229.5
- VW 502 00 / 505 00