When a part needs high temperature seals, there are no substitutes. These types of high temperature oil seals should never be swapped out for seals that are not designed to withstand the type of temperatures the parts will be exposed to. Instead, for the optimal in performance across the spectrum the appropriate peek seals should always be used.
Depending on the type of part that needs the high pressure seals, they could be made from a variety of different materials. Some examples are gaskets, rubber o rings and more. Spring energized seals are another example of the type of seals that could be used in a variety of different applications.
When it comes to repairing or replacing the worn out parts of a piece of machinery that has high temperature seals, it is best to use the same brand of seals the manufacturer used when making the part. Trying to save money and time by using cheap seals or seals that are not designed to withstand high temperatures will only lead to break downs that are often more costly than if the correct parts had been used in the first place. Read this for more.