BMW 11311432177 Upper Engine Timing Chain

The 6-cylinder (M54) engine utilizes a pair of chains to drive the camshafts, with a primary chain connected to the crankshaft that drives the primary sprocket on the exhaust camshaft, while the secondary chain drives the intake camshaft. Each chain is tensioned by a hydraulic tensioner. The timing for both intake and exhaust camshafts is variable and managed by the engine control module (ECM) through a system known as double VANOS. Service and repair of the camshaft timing chain necessitate the removal of the front crankshaft vibration damper, double VANOS unit, engine oil pan, and timing chain housing cover, so it is important to thoroughly review the procedures before beginning any work.