I have studied the UOA of a number of oils. I had the European Amsoil in my 04 Jetta on my first oil change at 120k miles (first TDI for us). The No. 2 intake lobe failed. I then went to the UOA on the TDIs and saw high iron in all of the TDIs with European Amsoil (no molybdenum, not enough zinc). I had Amsoil check the oil for an oil failure, it checked to their specs. My opinion is the wear probably started prior to but failed during this oil change then the oil did not do it's job to prevent further wear. I then chose Schaeffer 9000 5W40, it is full synthetic diesel oil with molybdenum as the extreme pressure component. (zinc is also good, Mobil TDT has zinc) The Schaeffer 9000 is not rated for the TDI however the UOA on the TDIs show it is very good for the TDI PDs. I have over 115,000 miles with Schaeffer 9000 with no cam wear (new cam). 2005 Passat TDI with Schaeffer 9000 and 80,000 on a new cam with no wear. 2004 Passat TDI also new cam with 55,000 miles and no wear. I do inspect the cams once per year. My neighbor who has millions in farm equipment only uses the Schaeffer 7000, a synthetic blend. The company has been around for over 80 years. I use it in my other vehicles (5W30 for the gas engines) and it is a low cost oil at $6.79/quart. I has not seen a better deal. I use 1 quart at 10,000 miles in the Jetta. They have a new blend that is replacing the 7000 and 9000 now. I have not checked the changes out yet.