The increasingly severe emission legislation for heavy duty diesel engines forces engine builders to modify their engine designs drastically. Together with a desire for longer drain intervals, this results in changes in engine oil specifications. Recently, a new ACEA specification for heavy duty diesel engine oils - E5 - has been added to the existing E1-E4 categories, and E1 has been withdrawn.The previous ACEA specifications - E1 through E4 - are sequential in the sense that each next category means an increase in performance. The new ACEA E5 specification, although it resembles an improved E3 product, breaks with this tradition in that it does not fall between the E3 and E4 specifications, but moves in a new direction regarding the formulation requirements. This is due to the inclusion of various API CH-4 tests that put an emphasis on the engine oils capability to handle soot. The consequences of this divergence on the formulation of heavy duty engine oils is investigated, especially in terms of extended oil drain intervals.A comparison between the performance requirements for ACEA E3, E4, and E5 and the resulting impact on lubricant formulation is presented. In addition a comparison to the evolution of US performance requirements is made. It is shown that the latest performance requirements such as ACEA E5 and API CH-4 have significant impact on lubricant formulations on both sides of the Atlantic. Although key requirements - soot handling, piston cleanliness, wear protection - converge, significant differences between high performance diesel engine oil formulations in Europe and North America still exist.