The Relationship between Sealing Performance of Mechanical Seals and Composition of Coolants for Automotive Engines

Because the mechanical face seals in automotive water pumps play an important role in maintaining the good performance of engines, they must exhibit reliable sealing performance and long operating life. Generally, the sealing performance of mechanical seals is closely related to the properties of the liquid to be sealed. Automotive engine coolants are generally formulated with a variety of inhibitors to prevent corrosion and erosion of cooling system parts. A few of these inhibitors have a detrimental effect on the performance of water pump seals.

In this paper, representative types of deposit formation on sealing surfaces are reported. These seals were taken from pumps that failed due to seal leakage believed to be caused by a combination of coolant formulations, contaminations into coolant, and changes in engine operation conditions. The failure mechanisms and possible countermeasures involving the sealing materials, surface quality, and seal structure are discussed.