An experimental investigation was performed to assess the effects using diethyl ether additive in a diesel engine fuelled with waste plastic oil. The variations in the performance, combustion and emission characteristics of the engine using plastic oil and its 5%, 10% and 15% blends with DEE were examined and compared with reference fuel. The experimental results show that the brake thermal efficiency increases with increasing percentage of DEE in the blends and also BSEC reduced considerably while using blended fuels. The combustion was delayed for DEE blends when compared to neat plastic oil and diesel. A drastic reduction in the levels of smoke and NOX was noted for blends at maximum brake power. There was an improvement in the CO emissions while operating with PO-DEE blends, however the UHC emissions were slightly higher. PD15 showed better performance and combustion characteristics with cleaner emissions. (C) 2016 Elsevier Ltd. All rights reserved.