This article provides insight into climatic wind tunnels in general and into the Modine climatic wind tunnel in Filderstadt/Bonlanden, Germany. New test capabilities and available calibration equipment are described. Influences on test results, induced by both test stand and vehicle, are listed and discussed. Differences between road and wind tunnel testing can typically be avoided with a state-of-the-art test facility and adapted methods. Even at high-speeds, test results should agree. Focuses of the article are: Wind speed adjustment: Vehicle test results with incorrect wind speeds show the importance of a correct adjustment. Therefore, a refined procedure was developed which is presented in detail. Vehicle fixing: Fixing of vehicles can be done in different ways. Preferred methods should not only be quick to apply and rigid enough to prevent movement of the test vehicle. They should also not disturb the oncoming air flow and the pressure distribution in essential areas of the vehicle like the cooling air inlets and the underbody. Vehicle instrumentation: Measuring systems, like flow meters, can have an impact on the test result due to their additional pressure drop. Methods for volume flow measurements on the liquid and the cooling air side with minimum impact on the cooling system performance are presented. Calibration of cooling system components on calorimetric test benches is recommended. To measure pressure coefficients on the body shell of a vehicle, a reference pressure is needed. For tests on the road, this is not trivial. A position would be desirable where the pressure coefficient at different vehicle speeds is always zero. Tests conducted on a correlation vehicle show that a position on the engine hood was most suitable. Test results on the road and in the wind tunnel are correlating well.