I was digging through our diagnostic, service and parts information system today and came across something interesting. I put in my vehicle information (2004 Volvo S40 with a B5244S non turbo engine with a 5 speed automatic FWD gearbox) and the oil requirements for all markets was displayed in the service category (I never go in there because all I need the system for is diagnostics). Something interesting came up: For cars in the EU, the oil requirement for the B5244S (my same engine) is a 0w30 ACEA A3/B3/B4, but in the US the requirement is a 5w30 ACEA A1/B1 and ILSAC GF-4 API SL. Why would the exact same engine require two completely different oils (A1/B1 compared to A3/B3) in different weights? My understanding is that A3/B3 is for extended drains, so I run Mobil1 0w40 for the full 7500mile service interval. When the oil comes out, it isn't even cloudy. It is dark, but almost a dark red color. What do you all think about this information?