95 525i coolant level sensor

160k on clock, coolant level indicator light comes on after startup, check levels and they seem fine, maybe too full, could this just be a sensor? And every once in a while I detect a faint coolant coolant odor, after stop and in front of car, no leaks found, again could this be from too full? This is a new purchase and not that up on bmw trouble shoot. There has not been an overheating issuse, coolant level is 3-4" above cold line when cold and almost to the top of resivior when engine is warm