Short muffles of air conditioning after starting the car

Hello dear Volvo community, for some time now my air conditioning has been so funny. Always so 5sec and then it’s over. Recently my elk was replaced by the dispersion valve. Since then, it seems to me, that’s grope. The car stands overnight in a garage and during the day outside the office. The smell is always strongest when my elk has stood longer – whether outside or inside. Otherwise, the smell does not appear. I have already read some threads on this topic, but did not really help me. Therefore my new thread. Does anyone have an idea what it might be about?