This experimental study examines how it affects a diesel engine's combustion, emissions, and performance. Plastic waste poses a considerable ecological threat, and its mitigation is imperative. The study evaluates diesel performance in comparison to a 20% blend of LDPO20 and manganese oxide nanofluids at 50ppm and 100ppm. Plastic oil was generated via pyrolysis, and its fuel properties, fatty acid composition, and useful compounds were experimentally evaluated. Manganese dioxide was synthesized chemically. Using an ultrasonicator and Tween 20 surfactant, LPO20 and MnO nanofluid were mixed evenly. Nanoparticles improved the fuel's ignition by increasing the surface area to volume ratio. Results showed the combination improves BTE, reduces BSFC, and decreases NOx, HC, CO emissions, and smoke compared to LDPO20 alone.