Genuine OEM Audi Engine Timing Chain Tensioner, part number 079109467AE. This vital component is responsible for maintaining proper tension on the engine timing chain, ensuring precise valve timing and smooth engine operation. It is a compact metal unit, weighing approximately 0.099 kg and measuring 0.063 meters in length. Choosing a genuine OEM chain tensioner guarantees the correct spring rate and hydraulic function for consistent chain tension, preventing slack and potential engine damage.