Now that I think about it, I also had a weep from the bottom of the water pump a couple of years ago - only when the engine and the weather was cold. I just pulled up the bolts, chucked some water system sealer in, and it stopped after a while. Never leaked when hot.
Same as the weep from my heads - only when its jolly cold outside.
The main thing is to ensure that you are not losing coolant when the engine is up to temp, and there is positive pressure in the cooling system. If it's OK then, then let it drip when it's cold. Like I said, if it ain't broke enough, don't fix it.
Works for me.
Think about the fuel that pees out of an SR1 Blackbird when it's on the ground and cold!