Non-definable, rare noise from the engine

Hello guys, for some time I’ve been driving a V40 1.8 with 122hp BJ 2004. So far he didn’t have any big flaws. Now I’ve noticed a noise which is very rare to hear (here in the video you hear it).Video noise Until now the noise has occurred when the engine has been cold. Today it has also occurred after a 20 minute drive. You can only hear it when the engine is running in the stationary gas, during the ride there is nothing to hear. I hope you can help me quickly and give me the fear that it might be something bigger. Greetings Max