GT: 64,700 MILES

1999 Pontiac Grand Am

Just bought this car three days ago. Oil was clean, didn't check the coolant, but was told it was full. Yesterday the coolant light came on. Put a little mixture in(mostly water), and the light is back on today. I checked underneath for an active leak (no dripping detected) and bought some new antifreeze (max protection). I will fill up with 50/50 mix. I will check the oil again, too. If all looks good, what could be the culprit? Loose hose or new pump needed? I have a warranty with deductible, but hate to pay into it three days after purchase!
January 2, 2007.

Probably a coolant level sensor located in the coolant reservior. You are not losing coolant?