Thanks for the responses, I am particularly thankfull to learn that its not uncommon.
The neck is cleanly broken off.
As far as other symptoms prior to this, the only thing that comes to mind is that I can't ever remember hearing the electric fans on the front running at all.
It had the flat seal replaced before I took delivery, (oil leak.
I had an alarm fitted, but all that did was stop the odometer (next project).
Right now I plan to buy (from ???)
Radiator (with metal inserts)
Top and bottom hoses
Would this be a good time to flush the engine cooling system or would that be tempting fate ?
1990 124, 300E 2.6 (daughter)
2004 Cayenne S, Fabspeed Cat Bypass, BMC Racing Filter
2000 Lexus RX 300 (Wife)
Retired 1999 ML430