THERE ARE NO VISUAL SIGNS OF THIS FAILURE UNLESS THE VALVE COVER TO THE ENGINE IS REMOVED. UPON REMOVAL THERE IS A METAL FRAGMENT THAT IS RUNNING LOOSE UNDERNEATH THE VALVE COVER. WHEN THIS METAL PIECE FALLS OUT IT CAN ENTER THE TIMING CHAIN AND CAUSE THE ENGINE TO SEIZE AND THE VEHICLE TO HAVE CATASTROPHIC ENGINE DAMAGE. THIS PART BREAKS OFF DUE TO A FAULTY DESIGN OF THE ADJUSTABLE TIMING MECHANISM (VANOS). A REDESIGN OF THE SYSTEM OR REMOVAL AND REPLACEMENT OF PARTS IS NEEDED TO SOLVE THE ISSUE FROM HAPPENING AGAIN. AS A TEMPORARY SOLUTION I HAVE REPLACED THE $1000 DOLLAR PART WHICH HAS THE POSSIBILITY OF FAILING AGAIN. PLEASE ADDRESS THIS ISSUE AS IT IS A WIDESPREAD ISSUE ON THE S54 ENGINE ON THOUSANDS OF HIGH END BMW'S AND LEADS TO A RIDICULOUS FEE TO FIX THAT CAN RANGE FROM $1000-$8000 DEPENDING ON SEVERITY. *TR