The problem is that an O-ring gasket from the distribution cover is leaking but in order to replace this 1$ part they need a lot of time (over 10 hours!) and a lot of other small parts so the final bill goes to something like 500$. This analysis was done at a Ford dealership after an oil change (did elsewhere) when it was observed that pink fluid was leaking from the water pump.

Initially Ford told me it's a leaking water pump but when they started working on it they noticed it was perfectly fine.

While the reception guy insisted this is very bad and I need to do this right away, the Ford mechanic was very helpful and told me I could live with this as long as I would check the cooling liquid level from time to time (especially on long rides) and always have some in my car in order to fill it up.
He said that the rate is small.

In the weekend I drove ~600 Km and this morning when I checked the coolant I couldn't notice any drop of level.

Did you encounter this issue yourself? Did you go with the expensive fix? Did the Ford mechanics lie about this being a complicated job to perform (10 hours) and with a lot of parts to be replaced? I was shown a list with ~20 parts (most of them gaskets, screws, stuff like that).

Which distribution cover on which engine? If you mean its the water pump that is leaking its not a simple job to replace as its driven by the cambelt.