This is the sound of a 3.0 TDI CDUC Audi / Volkswagen / Porsche VAG engine rattle after a cold start.
Had help identifying the rattle by Tom from HBT Techniek [ Ссылка ]. Thank you very much for your help! :)
You can hear the rattle at the engine start at 8-th second of the video. To help to identify the problem I started the engine for a second time.
During the second start the engine rattle can't be heard and there is a distinct difference in the sound between the first and the second start. The engine then starts and runs without sound difference while starting and running. This happens because the tensioner has build up some pressure and the chains aren't loose.
Hope you will find this video useful.
I have added the following ([ Ссылка ]) video where you can see a graphical view (soundwave) of the starting of the engine where you can see a distinct differnce in the wave form.
