- The primary function of an oil seal is to prevent the loss of oil from the sealed system while allowing the free movement of the shaft or other rotating components. This is achieved through the use of a flexible material that conforms to the surface of the shaft and creates a tight seal. The material used in oil seals is typically a synthetic rubber or a thermoplastic, which provides excellent resistance to heat, oil, and other chemicals commonly found in machinery environments.
Proper installation and maintenance of the valve cover gasket are essential to ensure its effectiveness and longevity. Regular inspection and replacement of the gasket when necessary can help prevent oil leaks and maintain the integrity of the engine. Adhering to recommended service intervals and using high-quality replacement components are essential for optimizing the performance and longevity of the engine's valve cover gasket.
Clean all dirt and oil from the housing, and set the new seal in place with its open (spring) side towards the engine.
Operating temperatures for engine oil seals (see Fig. 14.11 and cross-section of lip seal with garter spring in Fig. 14.22) vary widely, depending on engine design and location within the engine. Typically, the rear crankshaft seal is subjected to much higher temperatures than the front seal. Oil sump temperatures vary considerably, depending on provisions for oil cooling. This allows use of hydrogenated nitrile (HNBR), silicone, or acrylic elastomers for some seals in relatively low-temperature environments (120–140°C or 250–284°F). Standard fluoroelastomers (FKM), bisphenol-cured VDF/HFP/TFE terpolymers with 68–69% fluorine content, perform well in oil service up to about 160°C (320°F). More resistant fluoroelastomers are necessary for reliable long-term performance in more severe environments.
Operating conditions such as the engine’s temperature, position, size, pressure and shaft speed largely determine which individual oil seal composition is most suitable for every individual application.
Ultimately, oil seals are devices that help to exclude dust and dirt, etc., while at all times retaining the lubricant in the piece of equipment.