There is an imperative need to ensure biodiesel's long-term sustainability to fulfil the quest for renewable fuel resources. The technical problems which are correlated with the use of higher blends of fatty acids methyl esters in diesel engine need to be taken into account in order to avail the environmental and social advantages of biodiesel. The present 512 h long term endurance test performed with B40 (40% jatropha biodiesel + 60% diesel) fuelled modified engine has investigated the fundamental premise on the basis of the technical criteria of durability. Special focus has been given on certain phenomena that affect the engine utility life like lubricating oil dilution, deposits formation and oxidative stability. Experimental results indicated that modified engine can be successfully operated with B40. (C) 2015 Elsevier Ltd. All rights reserved.