In agriculture and the production of agricultural machinery there is a great demand for materials with high resistance to temperature effects. A special place is occupied by seals, because the characteristics of power units, their reliability, and the possibility of using them in certain conditions largely depend on their quality. The heat resistance of elastomers used as sealants in agricultural machinery is the ability to maintain performance to ensure sealing of joints when exposed to high temperatures for a long time. Heating initiates accelerated thermal aging, which causes a few polymer-destroying processes, while the most important material indicators, such as elasticity, strength, wear resistance, etc., change for the worse. The possibility of operating rubber seals at elevated temperatures is mainly determined by the composition and structure of the polymer.