This BMW had a substantial coolant loss from the engine, in the area of what is termed the “valley pan”. Service correction of this fault requires the removal of the intake manifold system, replacement of all seals and gaskets in the center engine area. While the manifold is removed, there are a number of vacuum lines and crankcase breather hoses which will need inspection and attention.
BMW has released an update kit on some of the early engine crankcase breather systems, this is prime time to install this update. As you can see from the photos, it is also a prime time to vacuum out and clean debris from the intake manifold area.