Modern German make automobile engines including BMW, Mercedes Benz, Audi, Porsche and Volkswagen all make use of variable valve timing. This allows a vehicle engine to be tuned and balanced between engine performance and engine economy (fuel mileage). Specific to your BMW is the VANOS (abbr. from German variable Nockenwellensteuerung) system for controlling both intake and exhaust camshaft timing. In 1999, BMW first introduced the single VANOS system controlling the intake camshaft. Current technology utilizes a double VANOS system controlling both the intake and exhaust camshafts and subsequently, the valves. This is effectively changing the timing of the crankshaft and the camshafts (four-camshafts in the double VANOS system). By adjusting the valve timing electronically based on system demands, torque can be optimized when needed, keeping a flat performance torque curve at a variety of rpms and loads.
There are two kinds of common noises that a VANOS will make just before it fails. The first can be identified as a rattle heard when the engine is first started. This rattle typically will stop within a minute of initial start up. This sound is often associated with the VANOS oil pressure accumulator which mounts into the VANOS housing. The second noise is more critical and can be described as a loud rattling noise that continues to get worse the longer the engine runs. This typically is an indicator that the internal seals have failed within the VANOS and is permitting the pistons to rattle against the housing. Although BMW recommends replacing the VANOS unit in its entirety, they can be serviced and rebuilt.
Whether you drive a Porsche, Mercedes Benz, BMW, Volkswagen or Audi, It is important to remember that today’s German performance vehicles can only perform to their optimum specifications if they are properly maintained and service. Remember to stop by and see the experts at German Auto Center to service your engine and have the oil professional changed by the experts at German Auto Center every 7,500 miles. At that time, we will be happy to inspect your VANOS for signs of a pending problem.
At German Auto Center, we will provide a complete estimate on returning your VANOS to its original performance levels. If you have any questions about your BMW, simply come by and visit our experts in Austin BMW repair at German Auto Center and we will be happy to assist you.