@vagtuning,
Buy a new one; those leaky ones are notorious, and there are updated versions now. That should solve the problem once and for all (hopefully).
Thank you for your reply.
I've also heard that leaky nozzles are a general problem. In my BMW (E46 Cabrio), I already had one leaking nozzle

(but it was covered under warranty;). So, in my case (with two cars), I've already had three leaking nozzles

.
I hope you are right and the modified ones last longer

.
Greetings.
Peter.