The change of rubber properties in laboratory and field conditions is not similar. The influence of aeration on rubber compounds used for dynamic shaft seals was investigated. A comparison was made for oil oxidation under field conditions, on seal bench test and using a laboratory rubber swelling technique with aeration. The aeration affected rubber compounds differently based on the type of polymer and type of oil. Using Fourier Transform Infrared Spectroscopy (FTIR) and changes in the rubber properties, a rubber testing condition was introduced to simulate changes to seal life.