environmental issues and conventional fossil resource depletion has directed the attention of researchers to seek clean or alternative fuels. biodiesel was introduced as an answer to day-to-day increases in diesel consumption from heavy machinery to locomotives. the availability from a wide variety of feedstocks (more than 350 crops) and the reduction in emissions such as carbon monoxide (co), unburnt hydrocarbons (hc) and smoke opacity has made biodiesel attractive among other fuel alternatives. some of its disadvantages include inferior cold flow properties and slightly higher nox emissions. expanded polystyrene (eps) counts for 22% of total plastic waste globally. proper recycling of eps at remote locations is practically not feasible. canola biodiesel is an effective solvent for eps. this work aims in dissolving eps at varied concentrations in canola oil biodiesel, and fueled on two modern diesel engines (a light-duty and a heavy-duty) and their performance, emissions are analyzed at different loads and engine speeds. the improvements that resulted after adding the additives (i.e., acetone, tetrahydrofuran, di ethyl ether, xylene and toluene) to eps-infused biodiesel are also noted on the same engines at various speed and load conditions. the cummins heavy-duty engine was powered by fuels at two idling conditions (700 rpm and 1700 rpm). the hatz light-duty engine was powered by fuels at low, medium and high speeds at 1000 rpm, 2100 rpm and 3000 rpm. the fuel properties such as calorific value, density, and viscosity of each fuel are also investigated. the microscopic structure and the particle size distribution of each fuel sample were evaluated to monitor the changes when adding eps, and any improvements when adding additives were noted.