For a couple of months I was loosing coolant but never saw a leak.

I finally found a pinhole leak in the heater hose near the firewall. Not enough to ever see any coolant, but it stained the gearbox rust colored. So I cut off 3cm of bad heater hose end and put it back on the head. Leak fixed. I took my 1200 on a 1200km trip and it didn't lose a drop of coolant. After sitting overnight, I loosened the cap and it still had a bit of pressure in it!