A few weeks ago my 06 Jetta TDI engine gave out due to cylinder head failure resulted from a worn cam follower. At the time a trusted TDI mechanic estimated the cost of R/R around $5500. It was a bad timing - car was just out of warranty. After a lengthy effort with dealer eventually with VWoA (VW of America), the issue was resolved - VWoA paid all the cost and now the engine runs just like new. I am posting a summary here in hope of providing a reference in case you run into a similar situation.
 
 lessons learned:
 1) retain service records.  in addition to service/part receipts, log  all services in a spreadsheet for each car each time with detailed info  like part, brand and model.  i have 3 cars, although 2 of them are  non-vw, when i submitted my service records, the spreadsheet for all  cars really showed that i had been consistently maintaining all cars in a  precise way as supposed.
 
 2) promptly report issues to manufacturer.  when my tdi was still under  warranty, i called vwoa to report heavy black smoke and burning oil  issues.  in last april right before my warranty ended,  i brought my car  in for cam lobe check-up, with a uoa showing high metal in the oil, but  dealer said no evidence of wear being found.   i didn't stop there; i  called vwoa to report the issues (and asked the rep to make a note under  the vin).  this time although my warranty had been out, vwoa was  convinced by my car history that the failure had been there but dealer  failed to diagnose the problems last year.  
 
 3) be nice with dealer service manager and vwoa regional case managers.   those people are human beings, they are there to help customers, some  of them are really doing whatever they can to help you out if you talk  to them in a nice way.  i met with dealer service manager only once,  talked with him on phone couple times and with vwoa case manager on pone  twice.  overall, they were very nice and really listened to me.   
 
 4) need patience.  some times they do need reasonable time to get things  done.  in my case, the dealer had to contact vwoa for decisions and  later they had to order a new cylinder head  from out of town (actually  it was a re-manufactured head as shown on the receipt).
 
 all in all, the dealer did a good job, i am satisfied.