How often should the engine belt of an Audi A4 be replaced?

[StCatherine]

The engine belt of an Audi A4 should generally be replaced every 80,000 kilometers. Function of the timing belt: The main function of the engine timing belt is to drive the engine's valve train, ensuring that the intake and exhaust valves open and close at the appropriate times to allow normal air intake and exhaust in the engine cylinders. Steps for replacing the timing belt: Remove the valve cover, detach the crankshaft pulley, and take off the timing chain cover; rotate the crankshaft to align it with the top dead center of the first cylinder, then tighten the crankshaft fixing screw to secure it. Rotate the intake and exhaust camshafts—there are grooves at the rear of the camshafts—align the grooves of both camshafts horizontally, and insert the specialized tool; remove the old chain and install the new one. The crankshaft pulley also lacks a keyway; during installation, align the round hole on the pulley with the groove on the timing chain cover.