Valve Stem Oil Seal 471710V CFW VA09 5-20 A23 For Peugeot 307

1.Positive seals

Description: These seals are fixed around the valve guide and are designed to wipe excess oil from the valve stem as it moves.

Function: They use a hydrodynamic design to meter the right amount of oil, which helps reduce oil consumption and emissions.

Common use: Found in most modern engines, including those with an overhead-cam design. 

2.Deflector (Umbrella) seals 

Description: These seals are secured to the valve stem and move with it, acting as a shield or deflector.

Function: They protect the valve guide from excess oil.

Common use: Often used in older pushrod engines and can sometimes be used in combination with O-rings. 

3.O-ring seals

Description: A simple rubber ring that fits into a groove on the valve stem.

Function: They prevent oil from leaking between the valve stem and the valve retainer, often working in conjunction with another seal type.

Common use: Frequently used on certain engines, such as some small-block Chevrolet engines. 

High temperature resistance

Chemical compatibility with common engine oils

Reduced oil consumption

Improved engine performance

Reduced emissions