To satisfy the global fuel economy restrictions getting stricter, various advanced cooling concepts, like active flow control strategy, cross-flow and fast warm-up, have been applied to the engine. Recently developed Hyundai’s next generation 4-cylinder 2.0L gasoline engine, also adopts several new cooling subsystems. This paper reviews how 3-D CAE analysis has been extensively used to evaluate cooling performance effectively from concept phase to pre-production phase. In the concept stage, the coolant flow in the water jacket of cylinder head and block was investigated to find out the best one among the proposed concepts and the further improvement of flow was also done by optimizing cylinder head gasket holes. Next, 3-D temperature simulation was conducted to satisfy the development criteria in the prototype stage before making initial test engines. A few design changes in water jacket to reduce the engine temperature or to enhance the productivity were considered and implemented on the developing engine. As new subsystems such as cylinder block inserts for fast warm-up, cylinder block embedded EGR cooler, cylinder head with an integrated exhaust manifold and so on have been applied to the engine, unexpected results occurred in the test phase. For each subsystem, the detailed physical phenomena have been studied with 3-D thermo-fluid CAE analysis and a remedy could be suggested. As a result, the cooling systems of new engine have been developed with sufficient thermal stability.