How are Oil Seals made?
Plug tube gasket
Polyacrylate Oil Seals - Mostly selected for automotive and transmission uses, polyacrylate seals are able to withstand fuel, oil, ozone, sunlight and weather when used. With cars exposed to all these different fluids and elements, they are the perfect choice. However, they should not be used in low temperatures, as their flexibility weakens when cold.
For a more detailed discussion of seal types and type codes, please see the following:
VMQ (silicone)
2. Temperature: Just like pressure, it is very important to choose the right seal that can withstand extreme heat or cold temperatures, depending on the operating environment of your application.
Does it mean the seal stops the leakage completely? Well, on the practical grounds yes because there is no ‘visible leakage’.