Due to the increasingly stringent emissions standards in the world and, on the other hand, the foreseen shortage of fossil fuels, the application of low viscosity engine oils (LVO) is considered one of the most interesting options for counter these threats. In parallel to a fuel consumption fleet test, the aim of this study was to assess the performance of commercial low viscosity oils regarding their degradation and engine wear, since the use of LVO could imply an increase in wear rate. Potential higher engine wear could result in a reduction in the expected engine life cycle, obviously is a non-desired effect. In addition, currently limited data are available regarding “real-world” performance of LVO in a real service fleet.On this test, 39 urban buses were monitored using a detailed and extensive oil analysis program, comprising two engine technologies (Diesel and CNG) and four different lubricants, two of them LVO and other two considered as a reference baseline, during an oil drain period of 30000 km. Samples were taken each 3000 km. For every sample, a broad list of physical and chemical properties was measured, and especially engine wear was quantified using ICP-OES, in order to assess wear patterns in the engine.Results indicate that oil performance and wear effects do not show abnormal patterns due to use of LVO.