When will we ever learn?
Ah, the cooling system DEMANDS to be checked every single time the engine is started, or restarted, or running, or in between.....
But we made the decision to stay put in Karlsruhe until the root problem was found and corrected, as we had too often been caught out by Sulina's unpredictable water cooling system, and we did not want to risk damaging the motor. And yes indeed, when we started the engine the very next morning, no water was coming through. It was clear that we couldn't travel until we found out what was wrong.
So it was arranged that Chris, a boat mechanic, would take a look and help us figure out the problem. Unfortunately, he proved to be quite unhelpful, though he did get us started on flushing out the system hose by hose.
Now, that may sound easy, but imagine sitting squeezed into the under floor space of the engine room, sweat pouring out of you in the sweltering heat, running into your eyes so you can't see, fighting with ancient seized-up jubilee clips, squirting water into the hoses and trying to catch it again in containers that are too small as the bigger ones don't fit down there. Oh yes, a fair bit ended up in the bilge.
We were helped by Robi, the harbour master, who came along later, and between the four of us, we found and fixed the problem, a loose clip that had been allowing air into the hoses, preventing the pump from functioning properly.
And since then, our old problem seems to be solved.
GUSH!