Licensing systems for engine oils

Crankcase lubricants for automotive and commercial use are differentiated by their physico‐chemical properties but more importantly by their performance in a series of engine test sequences. The sequences are devised by committees formed by representatives from the vehicle manufacturers, the oil companies and the additive suppliers. The article describes the sequences devised by the American Petroleum Institute and the European ACEA organisations, including some historical background as well as the current specifications. Methods of compliance monitoring and enforcement are also covered.