Genuine OEM Audi Timing Chain Tensioner, part number 079109217J. This essential component is responsible for maintaining the correct tension on the engine's timing chain, ensuring precise valve timing and engine synchronization. It operates within the timing chain assembly, often using hydraulic pressure to apply constant force. Constructed from robust metal alloys, it weighs approximately 0.26 kg. Choosing a genuine OEM timing chain tensioner guarantees the correct spring rate and hydraulic characteristics, preventing chain slack, noise, and potential engine damage.