i've got the same problem with my top radiator hose which was changed a year ago but had problems from the first few weeks. i can't be stuffed to do anything atm.
my overflow tank goes from max to minimum over ~3 months.
every few days drops of coolant are visible on my engine/next to the headers. when the car is running no leaks occur.
i think the pipe shrinks in cold weather which opens tiny holes for the coolant to drip out.
:confused:
i'm thinking of getting those blue silicon hoses or something.

