BMW N52 VANOS Solenoid Replacement – 1,3,5,6,7,X1,X3,X5,Z4 6cyl.

The term VANOS is an acronym for the German word variable nockenwellensteuerung, which when translated literally means variable camshaft control. The VANOS units are located on the front of the cylinder head and have the unique function of making small adjustments to the intake and exhaust camshafts while they are rotating in a running engine. The BMW VANOS units make these "variable" adjustments to the spinning camshafts in a very clever way; they harness hydraulic oil pressure to move a splined plunger gear back and forth on the end of the camshaft. When the splined plunger gear is extended, the camshaft timing is advanced slightly creating "valve overlap" and a more efficient running motor. When the splined plunger is retracted, the timing is retarded creating more engine power.

This delicate balance of extending and retracting the VANOS gear is controlled by the engine control module (ECM) and the VANOS solenoids. When the ECM determines the engine requires greater efficiency it sends a signal to the VANOS solenoid which increases oil pressure and extends the plunger gear. If the ECM determines more power is needed, it instructs the VANOS solenoids to lower oil pressure so the plunger gear is retracted. The ECM makes these decisions based on factors such as engine speed, load, and coolant temperature. This fine-tuning of the camshafts and valves by the VANOS solenoids helps create a more fuel-efficient, smoother running, and powerful engine.

Like all mechanical parts in the engine compartment, the BMW N52 VANOS solenoids have a definitive lifespan and will eventually need to be replaced. The classic symptom of failing VANOS solenoids is a lack of power when the accelerator pedal is depressed. It is usually accompanied with a "service engine" light in the instrument cluster and fault codes 2A82 and/or 2A87 on the diagnostic scanner. Other symptoms include a rough idle or a "rattling" sound from the front of the engine.

The good news is a BMW N52 VANOS solenoid replacement is a very simple repair for the home mechanic. The solenoid valves are very easy to access on the front of the engine and can be replaced by even the most novice mechanic. The BMW Repair Guide strongly recommends replacing the camshaft sensors while replacing the VANOS solenoids. For more information on replacing the camshaft sensors in your N52 six-cylinder engine, please see our article BMW N52 Camshaft Sensor Replacement – 1,3,5,6,7,X1,X3,X5,Z4 6cyl..