What's causing the noise coming from my engine when I accelerate?

My Audi Q3 140 TDI is four and a half years old, with a full five year Audi warranty. It has developed a low clatter, at about 2000rpm and noticeable particularly when the engine isn't up to full temperature, when accelerating gently. Audi accept there is a noise but don't know what it is. There are no other adverse signs and the car runs well. Any thoughts?
Assuming it's a manual, I'd suspect the Dual Mass flywheel (DMF).
Answered by Alan Ross on

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