BMW Repair: repeatedly replacing starter, battery voltage, mechanic

Question
Hi,
My daughter's 1992 318i keeps blowing starters.  They have been replaced several times.  The last time the shop did some work on the wiring but the starter has blown again.  Do you have any suggestions we can pass on to the mechanic. Although he has done some work on BMW's he is not a Bimmer specialist.  

Answer
It all really is basics,I have never heard of actually "blowing " a starter.There must be a ground or power problem if these units were new.If they were used they should be checked out  better for current draw.Clean grounds is my advice,as well as proper battery voltage to the starter.