Crystallize on the moving components, restricting their movement. Change fluid viscosity restricting the ability of the seal to follow run out. Solidify, making the seal inoperable. Build a film on sliding components and the lapped seal faces. Carbonize or coke restricting the seal movement and opening the lapped faces.
Corrosion always increases with increasing temperature.
A layer of calcium or some other similar product has built up on the jacket walls, interfering with the heat transfer. The coolant is flowing too rapidly through the cooling jacket. A thermal bushing was not located in the bottom or end of the stuffing box. If steam is being used as the coolant, the pressure is too high. There is either suction or discharge recirculation of the pumping fluid.