Genuine OEM Audi Engine Valve Spring, part number 03H109623C. This spring is a vital component within the engine's valvetrain, responsible for closing the engine valves after they have been opened by the camshaft. It is located within the cylinder head assembly, surrounding the valve stem. Weighing approximately 0.045 kg, this precision-engineered spring ensures consistent valve operation. Choosing genuine OEM guarantees the correct spring rate and material fatigue resistance, which are essential for reliable engine performance and longevity.