The growing interest on environmental issues related to vehicles is pushing up the research on reciprocating internal combustion engines which seems to be endless and able to insure to combustion engines a long future. Euro standards imposed a significant reduction of pollutant emissions and were the stimulus to favor the conception of technologies which represented real breakthroughs; the recent directives on greenhouse gases emissions further reinforced the concept of reducing fuel consumption and, consequently, carbon dioxide emissions.So, new technological efforts have to be made on internal combustion engines in order to achieve this additional target: several technological options are already available or under studying, but only a few of these are suitable, in particular, in terms of costs attendance per unit of CO2 saved.Among these technologies, a revision of engine cooling system seems to have good potentiality. In fact, the cooling system remained substantially unchanged during years and a number of innovations are close to be on the market. They do not consider yet an integration between the engine cooling system with the other vehicle thermal needs, in order to improve comfort and increase transient requirements.Concerning this chance, the Authors present a physically consistent mathematical model that describes the main phenomena about heat transfer on engine cooling circuits. The model was created in a modular way and it is an evolution of previous works that can solve the thermo-hydraulic field of an engine cooling system and can identify control strategies.Thanks to this, model novel opportunities of engine cooling systems can be studied in terms of integration among thermal requirements. In particular, the integration of a liquid cooled charge air cooler is considered and warm-up time reduction is achieved, with benefits on fuel consumption and emissions.