When crank bolt loosened, timing belt. etc bent valves leading to think of rebuilding the head. Instead, my local audi dealer sold a remanufactured head for about 520.00 to my mechanic. Not all audi dealers are that competitive. If you are intereste in one, let me know and will check their current pricing. Perhaps they can ship it directly to you from the wharehouse George K jkot@pitt.edu