Re: A6 2.7 TDI V6 - Cambelt or chain? – 06-01-2009, 02:12 PM. If you are referring to a BPP engine code then there are four chains one for the balance shaft and oil pump, one to feed the the two cam idlers and one to feed each cam, and a toothed belt driven Injector pump. Regards Peter. 0 0 0. 2. The bottom timing chain cover sealant was expired. Audi specifically tells to check the expiration date before applying it. I was told by Audi parts store that it's good for another 3 months after the expiration date. Didn't want to take any chances and purchased a replacement from a local dealer. 3. included in this interval. Air filter - Clean housing and replace filter First at 55,000 miles and thereafter every 60,000 miles S8 4.0L V8 only Air filter - Clean housing and replace filter First at 55,000 miles and thereafter every 60,000 miles Except RS5, TTS, S6, S7, RS7, A8 3.0L TFSI, A8 3.0L TDI, A8 4.0 TFSI DIY Difficulty: Intermediate. 6. Stretched/Skipped Timing Chain Issues. Lastly, another not too common issue is the timing chain stretching or skipping in the early VW 2.5 engine. A timing chain allows the camshaft, crankshaft, and balance shaft to rotate in sync. Without the timing chain, an engine would be useless. xUzy3w.