I have a '91 LS Coup that seems to have a very slow leak in the cooling system that I cannot identify. After driving the car, there is the faint smell of anti-freeze coming from the engine compartment. I cannot see any fluid anywhere, and it does not drip on the garage floor. The coolant level in the resivoir goes down very slowly (it went from MAX to MIN in the span of about 3 months). I am thinking that maybe it is a leak in the radiator that is so small, the fluid evaporates before it gets a chance to collect anywhere. The radiator does have 119,000 miles on it, and most of those miles were spent in the winters of Minnesota and in the Colorado Rockies. Any suggestions other that the radiator? I am not ruling out a head gasket, but the fact that I can smell anti-freeze leads me to believe this is not the problem.