Genuine OEM Volkswagen Drive Belt Tensioner, part number 022145299D. This critical component ensures the correct tension is applied to the engine's serpentine or accessory drive belt, preventing slippage and ensuring proper operation of accessories like the alternator, power steering pump, and air conditioning compressor. It is typically mounted on the engine block. Constructed from robust metal, it weighs approximately 0.944 kg. A genuine OEM tensioner provides precise tensioning and durability, crucial for preventing belt failure and maintaining accessory function.