You've tried to check around the engine to locate where the noise is coming from?

If you can't locate it under the hood, then, just a guess, but it could be the starter is not completely disengaging from the flywheel. If you can detect the noise near the starter, try spraying it with WD-40 or other lubricant.

 

Thanks for the reply. I will check the starter but I think the noise comes from the back of the engine. Yesterday I found a video of a guy with similar noise and he claimed that the timing chain was the problem. As far as I know (correct me if I’m wrong) the tensioner is hydraulic and if you don’t drive the car it loosens and when you start the engine it takes some time to tighten the chain back.

 

Try changing your oil and use a genuine oil filter. Make sure you use the recommended oil. Is it cold where you are at the moment because that could play a part if the oil is old or not the correct weight.

 

That is possible.