New vehicle generation offers increased comfort and capabilities, for a price - more complex chassis tunings and powertrain calibrations. Thus traditional hot cells and bench tests to size, design and release vehicle systems are now backed up more and more often than in the past by proving ground, track and real road checks. To investigate thermal vehicle behavior, anticipate issues, support diagnosis and evaluate different drive patterns or environmental conditions system simulations have to be improved too, yet kept as simple as possible to provide quick answers. This paper explores feasibility of coupling crude vehicle and engine usage estimations for a given test run as boundary conditions for CFD 1d Flowmaster engine cooling system model.