I currently have a 96 Z24 and I bet the level sensor might be dead or dirty. I dont know how much you know about working on your car but if you can drain some coolant from the bottom, the reservoir will be empty and you can take it out and flush it with a hose, mine had a lot of dirt in it once when it was stuck on. It goes on every once in a while because I actually have a leak somewhere on the heater hose anyway. That may help save you some money for getting a new sensor but I think they are kinda cheap anyway. I'm in the same boat as you just trying to make mine last until I can get my camaro and I recently hit 140,000 miles!