I noticed around 4 weeks ago that the coolant level on my Fiat Panda was just below minimum when cold. Therefore, I topped up the coolant with water and left it. The car ran fine and the coolant level never moved. Today, I decided to check the coolant level before setting off on a 2 hour drive only to find that the coolant had dropped (not lower than min) but it had dropped a couple of inches. I'm not sure if it is leaking fluid - there are no signs, the oil cap is free from white substance (so no head gasket trouble, I hope), the water pump has been recently changed by a Fiat dealership (so I doubt it's leaking) and fFiat gave the car a clean bill of health after carrying out a health check (though this was about 3 months ago). Do you have any idea why it could be losing coolant?