[MOTORHEAD]

I may have found the answer to the "disapearing coolant " mystery:
Being retired, most of my memory cells have also retired, but one must still be active, as I remembered that I own a Coolant Pressure Test kit ! I never had considered a leak, as non were ever visible, but pressurizing to 13# showed leakage at every hose end clamp.
Tightening ensued and leakage stopped.
( "Under Pressure" by David Bowie playing in the background ) My new theme song.