From this kind of standard immersion testing, one would expect that bisphenol-cured VDF/HFP/TFE fluoroelastomers would not give good service life as oil seals. Similar tests with other elastomers, such as HNBR, silicone, and acrylic rubbers, show less loss of elongation. However, it is found that, in actual service, FKM shaft seals6 have much longer service life than seals of the other elastomers. In a Japanese study of FKM lip seals, rear crankshaft seals from high-mileage automobiles (70,000–280,000 mi ie, 110,000–450,000 km) were collected and examined. No serious oil leakage was found when the seals were removed from the engines. Some deposits were found around the seal lip and on the garter spring holding the lip against the shaft. No surface cracks were found on the seal lip, and only minor crazing on the crankcase side of the flexure portion of the seal in some samples. The seal compositions were not noted, but most were probably VDF/HFP/TFE elastomers with 68–69% fluorine content.
In conclusion, the oil tank gasket may be a small and often overlooked component of an oil tank, but it plays a critical role in maintaining the tank's integrity and preventing leaks. Regular inspection and maintenance of the gasket can help to prolong the life of the tank and ensure its safe operation. If you suspect that your oil tank gasket may be damaged or worn, don't hesitate to replace it to avoid potential problems in the future.