We have run into several cases of 2004-2006 Volkswagen and Audi TDI that came in with a loud engine ticking noise and possibly with the Check Engine Light illuminated. It is unclear if lack of oil services or using improper oil is the cause of the camshaft and lifter failure. VW recommends engine oil VW spec 505.01. We find that it is most common for #1 and #4 intake lobes and lifters to fail first. We have not seen any information to explain this occurrence or proof that lack of oil services can cause or increase the likely hood of this occurring. On the vehicle shown, it was #1 intake camshaft lobe and lifter that failed first and had the most damage. Because of the specialty tools required and very technical nature of this repair it is not recommended that this repair be performed by anyone that is not a skilled and trained VW | Volkswagen Technician. If you think you may be experiencing this problem, the sooner you can get it inspected the less damage will occur. If you live anywhere near the Temecula, Murrieta area and are looking for an expert VW | Volkswagen Service and Repair Specialist, please feel free to give us a call. We will provide you with the Best Customer Service Experience in the Automotive Industry.