If the seal is being fitted to original equipment you may have some influence over the shaft and housing bore finish, but if you are replacing a worn seal you still need to take into account the condition of these 2 essential parts.
Rotary Wheel Of Auto Parts
Silicone (VMQ) Oil Seals
Rotary Wheel Of Auto Parts
Selecting the right oil seal involves comprehensively evaluating your application’s needs and conditions. Below are the key factors to consider when choosing an oil seal:

Modern engine oils, such as the current SG classification for gasoline engines, contain a large fraction of additives, many of which are detrimental to fluoroelastomers. The primary functions of oil-additive packages are to protect metal parts, avoid deposits in the engine, minimize oil degradation, and adjust fluid viscosity. Little attention has been paid to avoiding damage to rubber seals. Instead, elastomer producers have been expected to provide new, higher-performing products at no increased cost to auto manufacturers. Among the additives with moieties that may attack fluoroelastomers at high temperature are detergents (phenolates), dispersants (succinimides, alkylphenol amines), and antioxidants (amines, sulfides, hindered phenols).4 Many of these components are multifunctional, containing phenol or amine groups that can dehydrofluorinate and crosslink VDF-containing fluoroelastomers, leading to loss of elongation and eventual embrittlement. However, the rate and extent of reactions with seals are affected by many factors, including whether air is present in the system. When oil is exposed to air at high temperature, additives may undergo considerable changes. For example, a significant fraction of amines may be oxidized to amides, which have little effect on fluoroelastomers.5
4. Protecting the shaft from damage helps optimize your oil seals’ efficiency.
Prepping for Oil Seal Installation
DIN
Detergents: This additive isn’t like your laundry detergent! It focuses on preventing deposits, rust, and corrosion from forming on the piston ring area, piston under-crown, and other surfaces that tend to overheat.


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.