Castrol Magnatec 10W-40 A3/B4 is suitable for use in gasoline and diesel engines where the manufacturer recommends an oil viscosity of 10W-40, specification API SL/CF, ACEA A3/B4, A3/B3 or earlier. Castrol Magnatec 10W-40 A3/B4 is also approved for use in VW Group cars requiring VW specification oil501 01/ 505 0010W-40 viscosity and in Mercedes Benz cars that require MB-Approval 229.1 specification oil, 10W-40 viscosity.