In a recent check up of my new to me M5, my mechanic found the valve clearances to be below the recommended values (I can't remember exact numbers but .028 seems to be stuck in my head). The gist is that they are tight as opposed to loose. This is a bit beyond me. Can anyone help me out by explaining what is going on, what causes this, was this done by the po to cover anything up, how quickly should I rectify this situation?