2003 Chevrolet Silverado 1500 - Timing Belt Tensioner Pulley

The timing belt synchronizes the piston stroke of the crankshaft to the valve timing of the camshaft(s), and is a rubber belt with gear-like notches that interface with the crankshaft and camshaft sprockets to keep these components in time. Timing belt tensioner pulleys allow the timing belt to stay taut against the timing gears for optimal performance and energy transfer, and the tensioner allows the timing belt tension to be maintained as the belt stretches over time.