Does it mean the seal stops the leakage completely? Well, on the practical grounds yes because there is no ‘visible leakage’.

Chinese spark plug manufacturers adhere to stringent quality control measures to ensure that their products meet industry standards and specifications. Advanced manufacturing processes, precision engineering, and rigorous testing protocols are employed to produce high-quality spark plugs that deliver reliable performance and durability. Manufacturers prioritize material quality, heat resistance, and electrode design to optimize the spark plug's ignition capabilities and longevity.
Valve Cover Gasket: Role in Engine Functionality

Maintenance and Replacement of Seals:
Oil seals, also known as shaft seals, are radial lip type seals which are primarily used for retaining lubricants in equipment having rotating, reciprocating or oscillating shafts. The rotating shaft application is most common.


Viton Oil Seals - A synthetic rubber and fluoropolymer elastomer, Viton is used to make oil seals that provide resistance in both high temperature, up to 250°C and low compression set components. They also offer a high resistance to chemicals and abrasions, so they can be used in elements that regularly interact with petroleum and solvents.