This multi-ribbed belt transmits drive from the engine crankshaft pulley to the accessory drives, including the alternator, water pump, and air-conditioning compressor. It runs on the front of the engine and maintains tension through a spring-loaded idler pulley. A worn belt slips under load, causing flickering charge-system lights, reduced coolant circulation, or a squealing noise at start-up. The original belt matches the pulley groove profile and the stiffness of the original rubber compound, which keeps the accessory drives at their designed rotational speed without flutter. On replacement, inspect the idler pulley bearings and tensioner travel for wear.