I feel kinda dumb asking this, but I have never had oil heat before. I had noticed the smell of oil before when the tank was just filled, but the smell kinda hung on with the last filling. When I went down into the basement to check it out, I found a small pool of oil and assumed that the tank was leaking from the bottom. Upon closer examination tonight, it appears that the tank is leaking from the top. Does this mean that the tank was over filled or that my tank is leaking? Two people that I asked about this told me that there is some kind of whistle that tells the driver when the tank is full, but that's not an auto matic shut-off, right? Was my tank over-filled or do I have a leak?