As the modern era demands of communication by means of transportation, the demand for automobiles has risen to peaks. Consequently, it has become a great difficulty for the manufacturers to give an efficient and powerful engine for the necessity of the customer. The transmission system, fuel/air supply system, lubrication system, air/coolant cooling system etc. and various other system affects the performance of the engine. Hence, it is necessary for considering these performance attributes by designing an engine for better performance, where the cooling system plays a major role. Designing, maintaining and testing of engine cooling system must be maintained properly for better performance of the engine. This review focuses on the design of radiators to improve automobile radiator efficiency and testing of radiators. Many varieties of research papers have worked on the variety of methods that the radiator efficiency changes at the variation of mass flow rate by use of tubes, core, different nanofluids (coolants) and fan. In this literature study, it will be seen that different methods are used to increase the radiator's efficiency, among them radiator coolant is the most used one to improve the radiator's efficiency by addition of nanoparticles in coolant and modification of radiator's tube and fan. © IAEME Publication.