Genuine OEM Volkswagen Timing Chain Tensioner, part number 03F109507B. This essential component ensures the timing chain maintains optimal tension, preventing slack and ensuring precise engine valve timing. It is typically located within the engine's timing cover assembly. The tensioner is a robust mechanical or hydraulic unit, measuring approximately 87mm in length and weighing 0.147 kg. Genuine OEM timing chain tensioners provide the exact spring force and damping characteristics required for reliable engine operation and longevity.