In Ethiopia, there is a huge demand for single-cylinder engines for agricultural, construction, and related non-automotive industry application which is tried to be covered by imports with foreign currency challenges. It is quite difficult to get an engine at the right time mainly due to foreign currency issues. Furthermore, cost and performance are the main technical challenges of imported engines, low price leads to low performance and high performance demands a high price. Therefore, it is essential to adopt the technology for local fabrication by considering the socio-economic challenges and performance requirements in the Ethiopian context. This work is intended to contribute to such an ultimate goal by solving the overheating problem, one of the major problems faced by users on low-performance-low price engines. This was planned to be achieved by re-designing the engine cooling system aiming at improving its thermal performance by benchmarking the existing imported engines. Based on the specifications of the existing engine, the redesign process was carried out by the standard reverse design processes such as concept development, modeling, analyzing, and interpreting. For the re-designing purpose of improving the thermal performance of the engine, the transient thermal thermal analysis was conducted on the re-designed and original cooling systems. Throughout the re-design process, CAE/CAM tools such as Solidworks 2019 and ANSYS workbench were employed, and also the measuring and testing equipment such as spectrometry, and dimensional measurement tools were used to develop input data. The results indicated that the new design has improved an 18.4% temperature reduction at the cylinder liner boundary, a 22.7%-33.4% improvement in the adjacent cooling water temperature, and a 57.2% improvement in heat rejection rate. The analysis result is higher by 1.91℃ than the test result which is a 4.24 % variation. Keywords: Transient thermal analysis, Overheating, Thermal performance, Internal combustion engine, Re-design, Cooling system