ACEA is the Association des Constructeurs Europeens d’Automobiles, which represents the interests of European car, truck and bus manufacturers. ACEA standards are split into 3 main categories:

• A/B: – Engine oils for gasoline and light duty diesel engines.
• C: – Catalyst compatible oils for gasoline and light duty diesel engines with after treatment devices.
• E: – Heavy duty diesel engine oils.

Each category is further sub-divided with a letter designation e.g. A3/B4, A5/B5, C2, E7.