I have a 2001 Chevy Malibu and have replaced the engine coolant in it twice in the last six months after the low coolant warning light came on, and the light has recently come on again. The climate is mild here so there's no risk of freezing, and I do keep an eye on the temperature gauge - it doesn't seem to go very far above 180 degrees F in steady-state, which is about 10 degrees above where it sits with full coolant.
Is it safe to continue driving with low coolant as long as I continue to watch the temperature gauge? If not, what are the potential risks involved?
About a week or so after my original post, I decided to refill the coolant reservoir yet again and hope for the best. Not 48 hours later, I was on my way up a hill and suddenly the temperature gauge spiked up to the red line. I immediately stopped driving and had my car towed to the nearest repair shop. Turns out the intake manifold gasket had failed which was causing the leak. Fortunately there was no damage to the engine, but unfortunately the manifold is apparently very inaccessible in the 2001 Malibu, requiring more time to replace it. $1600 and 24 hours later (which included a coolant flush and two oil changes, the first of which was to clear out coolant contamination), my car was running fine.