Genuine OEM Audi Engine Valve Spring, part number 078109623B. This essential component is responsible for closing the engine valves precisely after they have been opened by the camshaft, maintaining correct valve timing and cylinder sealing. It is located within the cylinder head, acting on the valve stem. Measuring approximately 0.045 meters in length and weighing 0.041 kg, this spring is engineered for consistent tension and fatigue resistance. Using a genuine OEM valve spring ensures the correct spring rate, material quality, and heat treatment, which are vital for reliable valve operation and preventing valve float at high RPMs.