If you had the coolant hoses replaced this summer, I would bet that the clamps have probably loosened. Well, they haven't loosened, the rubber of the hoses has settled into it's new compressed form under the clamps. It seems to be a "normal" occurence that new hoses leak upon cold start up, and sometimes just sitting, a few weeks after new hoses get installed. After warm up, the rubber expands and re-seals. Giving the clamps a one-time, tightening up (I use a nut driver or a small 1/4" ratchet, instead of a screwdriver to get a little extra twist on the clamps) usually solves the leaking issue for good.