This book presents selected papers from the 8th International Conference on Mechanical Engineering Research (ICMER 2025), held in Kuala Lumpur, Malaysia, on August 7&8, 2025. The papers present cutting-edge research and technological advancements in mechanical engineering covering four major topics: (1) Sustainable engineering-Eco-friendly systems, waste management, flood mitigation, smart agriculture, environmental monitoring, biofilter design, fire resistance, and green technologies that support sustainable engineering practices; (2) Energy efficiency and renewable energy-Investigations on hybrid solar vehicles, EV air conditioning, phase change material-based thermal energy storage, water turbines, bio-lubricants, hydrogen fuel injection, emissions, and energy optimization; (3) Smart systems, artificial intelligence and IoT-Applications of artificial intelligence, machine learning, sensing systems, acoustic signal analysis, drone-assisted image analysis, IoT-based monitoring, smart pump systems, driving simulators, and data-driven reliability analysis; (4) Fluid, process and industrial engineering-Studies on layout optimization, microbubble generation, enhanced oil recovery, porous media, permeability, and holography-based measurement systems for industrial and process applications. This volume is an essential reference for postgraduate students, academics, and professionals in mechanical engineering and related fields. Addressing key challenges in sustainability, energy, smart systems, and industrial processes, it offers insights into emerging trends, innovative solutions, and future directions shaping sustainable and intelligent engineering applications worldwide.