Herein, we investigated and analysed the performance and characteristics of a compression ignition engine on methanol/diesel blends and the impact of engine loads on tailpipe emissions and engine performance. Four combinations of blended methanol were tested and compared with pure diesel. Engine characteristics, such as: brake thermal efficiency, brake specific fuel consumption and brake power were analysed. HCs and CO emissions followed similar trends. The highest HCs concentration reached 40 ppm at lower load (L1) for pure diesel and 5 ppm for blended fuel at a higher load (L5, B40). NOx emissions showed a different trend, showing a higher concentration of 640 ppm for higher load (L5, B40) and the lowest concentration appeared at lower load (L1) for pure diesel. For each individual load, with blended methanol at different percentages, NOx has increased with higher methanol blends. Whilst with HCs, CO emissions were reduced with an increased percentage of methanol addition. Additionally, smoke emissions were significantly reduced by increasing the methanol percentage in methanol/diesel blends. Pure diesel at all engine loads showed higher brake thermal efficiency and lower fuel consumption. The highest brake specific fuel consumption was found at lower load (L1, B40) and reached up to 0.75 g/kWh. Display omitted •Characteristics of diesel engine with methanol diesel blends were investigated.•Tailpipe emissions were influenced by engine operation and fuel blends.•Methanol diesel blended fuel showed improvement in engine power.•Brake thermal efficiency was decreased when methanol diesel blends introduced.•Methanol diesel blends improved engine performance and reduced smoke emissions.