Always but an oil that is either API (American Certified) or even better ACEA (European Certified) if it isn't then stay well clear.
Category for low-viscosity engine oils with particularly low High Temperature High Shear viscosity (< 3.5 mPas). Recommended viscosity grades are XW-30 and XW-20. A reduction in fuel consumption of = 2.5% compared to a 15W-40 reference oil must be proven in a Mercedes M 111 test engine.
Category for conventional and low-viscosity engine oils.
Category for conventional and low-viscosity engine oils with greater demands than ACEA A2. Out-performs ACEA A2 with regard to Noack (evaporation losses), piston cleanliness and oxidation stability.
A5 Testing as for ACEA A3 but with proven reduction in fuel consumption and lower HTHS viscosity.
New ACEA specifications were introduced in November 2004. In future, the specifications will apply in combination to both gasoline and diesel engines. Car gasoline (Car gasoline and diesel engines) and diesel engines Valid from 2004
Category for Fuel Economy engine oils with especially low High Temperature High Shear viscosity. HTHS of 2.6 to 3.5 mPas applies to XW-20, 2.9 to 3.5 mPas for all others. Corresponds to the old A1 and B1 specifications with some new engine tests.
Basic requirements. Will be replaced by the GLOBAL DLD-1 specification.
Category for high-performance and Fuel Economy engine oils. Exceeds ACEA A1/B1 with regard to Noack (evaporation losses), piston cleanliness and oxidation stability. Extended oil change intervals possible.
Same as A3/B3 but also for direct injection diesel engines.
Category for high-performance engine oils. For TDI engines with Fuel Economy Performance. In addition with lowered HTHS (2.9 to 3.5). Extended oil change intervals possible.
Engines LOW SAPS
An additional category appears in these specifications in which sulphate ash, phosphorous and sulphur content (SAPS) is limited.
Largely based on the ACEA A5/B5. Strict limitation of SAPS content. Low HTHS viscosity of >2.9 mPas.
Same as C1 but with somewhat higher SAPS content permissible (as with C3).
Same as C2 except for HTHS > 3.5 and without Fuel Economy performance.
Same SAPS content as C3, HTHS viscosity as C1.