What is causing the coolant reservoir return tip to break on my ML350 model 2004

What is your question?

I keep on mending the the reservoir tip and filling with the anti freeze, but soon as the engine heats up or I run the vehicle, the vehicle temperature rises drastically and the mended tip breaks off, causing coolant to leak out.

What makes this problem better or worse?

Tip breaks when I run engine

How long has your 2004 Mercedes-Benz ML350 had this problem?

one week