Couldn't make it...

Had a similar situation with my BMW. I would need to add coolant every few days or so yet no indication of where the coolant was going. As previous poster mentions, check your exhaust for white hue and coolant smell preferably when you first start the car at the beginning of the day. What happened for me was that I had a small hairline crack in the cylinder head between the piston and the exhaust port. When I shut the car off, the hot coolant would leak into the cylinder and then blow out the exhaust the next time I started the car. It is very noticable when the car is cold. It almost looks like you are burning oil but goes away as the car warms up. I hope this is not the case for you though as it was a very costly repair.

Good luck.