[sortkaffekop]

In the first post I got clever leads as to what the rattling noise could be.
Then - with this knowledge at hand - I opened this thread - because I want to drive, and if possible, wait with the repair to the winter. (Opening the inlet manifold is NOT a 5 min job...) My car does not have pressure gauge - just a warning light. And cant reach the tube without opening manifold.

I now hereby conclude that I will leave it for now. Case dismissed