Abstract: With the help of field experiments, a 1-D/3-D coupled simulation model between automo-tive engine cooling systems and engine cabin is established. Through these experiments and coupled simulations, the influence of engine cabin on the performance of engine cooling system and thermal flow field has been analyzed, and convective heat transfer coefficients on the engine surface which contacted with engine cabin’s thermal flow field have been summarized. These heat transfer coeffi-cients provide basic arguments for developing engine cooling system efficiently.