Could a thermostat that is stuck open cause the "coolant low" light to come on in a '94? The light came on, I pulled over & checked everything. Coolant was in the overflow. There was pressure in the hoses but not alot. The radiator was full & there was coolant to almost the top of the burper tube. I let it cool down for about 15 min. After that, I was back on the road, light was off until about another 100 miles down the road then it came back on again. Temp gauge showed everything to be normal but the light was still on. I wasn't getting much heat either. Car ran like normal. I did notice that fuel milage wasn't the greatest but it's been a while since I've taken it 500 miles and (like the rest of us) I have a heavy foot.