Engine Timing Belt Hydraulic Tensioner for AUDI A4 B5 A6 C5 1.8T, 06B109477A
Function: A belt tensioner is a system that guides the serpentine belt and the timing belt on a car engine. The function of a pulley and a tensioner is to limit the belt slip. for AUDI A6 C5 Saloon 1.8T 1997-2005 2.0 2001-2005.