High working temperature significantly shortens the service life of hydraulic pump shaft oil seals because heat directly affects material properties, sealing force, and wear behavior. In normal operation, the oil seal must maintain a stable lip contact against the rotating shaft while being lubricated by a thin oil film. When temperature rises too high, the elastomer gradually loses elasticity and may harden, soften, crack, or take a permanent set. These changes weaken radial pressure and make the lip less able to adapt to shaft vibration, eccentricity, and pressure fluctuation. In addition, higher temperature often reduces lubricant viscosity and increases friction, which accelerates wear at the sealing edge. Thermal expansion of surrounding metal parts can also alter the installed fit and contribute to deformation. Once sealing performance declines, oil leakage, contamination ingress, and reduced hydraulic efficiency follow. Preventing heat-related failure requires not only suitable material selection but also proper cooling, lubrication management, and correct shaft finish. Industrial seals designed for hydraulic pump shafts offer improved temperature resistance and structural stability, helping hydraulic systems in industrial equipment, construction machinery, and heavy-duty power units operate longer with lower maintenance frequency and improved sealing reliability.