Thank you for all your help!
I found and ordered this one:
https://www.pumpen-peters.de/products/Schlauchverbinder-T-Stück-16-mm%2C-5%7C8-Zoll%2C-Messing%2C-Benzin%2C-Öl%2C-Diesel%2C-Wasser%2C-Luft/5/1149/
After some search I noticed a very important thing: some of the plastic is resistant against all kind of petrol, but it has problems with
antifreeze!
Greets René
And John V6: I must work on my english! A string isn‘t a string…
