Dilution of engine oil with unburned fuels alters its lubricity and tribological properties. In this research paper, SAE-40 lubricating samples were contaminated known percentages (5%) (diesel, palm-sesame biodiesel blend (B30), B30 + ethanol, dimethyl carbonate, carbon nanotubes and, titanium oxide). The effect all these on wear frictional characteristics was determined by using a 4-ball tribo...