Our 2015 Kuga (2.0 180 4x4) is losing coolant, but very very slowly. About a pint a month i'd say. There are no obvious leaks anywhere but you can smell it when the weather warms up. I initially thought it may be the seal on the expansion tank cap, but that wouldn't give that familiar 'curry' smell of hot coolant would it? Whatever it is seems to be on that side of the engine. Any ideas?