for months I smelled anti freeze in my 94SC4 with 150K miles on it, but couldn't find a leak. I would top off the tank every now and then. the only symptom I had was the heater would cut out when the water was low. I was on a 400 mile out of state trip and found I needed water again. while I was topping off I heard a rattle like a bad pulley bearing. I headed for home keeping my fingers crossed that I'ld make it and twice had to add more water, but I made it.
I found the noise wasn't from anything running on the accesory belt. so off
came the front of the engine and found the noise and leak were from the water pump (which is driven by the timing belt). the belt was in bad shape and the pump bearing just about frozen tight and leaking. BIG job, but a lesson in maintenence - if your SC4 has this kind of mileage, and the symptoms above, swallow hard and replace the belt, the water pump and the rest of the pulleys because you don't want to do this job more than once, it is mi$erable.
and we all know what happens when the timing belt breaks.