Abstract This article shows the research results and the analysis of the engine properties of diesel fuel, rape seed methyl ester and methanol (M). In the test two blends, 30 V/V% biodiesel (FAME, B30) and 30 V/V% FAME with 10 V/V% methanol (M, B30 + M10) were investigated compared to the reference diesel fuel (D). These properties were researched using an Audi 1.9 TDI 1Z compression ignition (diesel) engine loaded in wide range BMEP = 0.236–1.203 MPa ( M B = 36–179 N m) and 4 speed regimes in range n = 2000–3500 min −1 . The change of energy and ecology properties during engine work on different fuels was analysed as well dQ / dφ max and dp / dφ max for the assessment of thermal and mechanical load of engine parts. While BSCF increased up to 3.5% for B30 and varied in range of 2–13% for B30 + 10M the BTE increased 1–2% and 2–2.5% respectively. The part of ecology indicators improved by adding M to B30: high engine loads characterized by 2–13% reduced CO and whole engine load range – 13–45% reduced concentration of soot. However emission rates of NO X , HC and CO 2 were close to or higher than reference diesel fuel (D). Research of thermal and mechanical load criteria (values of dQ / dφ max and dp / dφ max ) showed that the additive of M to B30 blend has no such a strong effect as expected.