I’m having an issue with my Monte I keep loosing coolant and it’s not all the time. I drove about 80 miles and I didn’t lose a drop but today I drove about 30 miles and I lost all of what was in the reservoir. I can’t find a visible leak. I changed the plugs and they looked fine to me. I just don’t understand what could be happening. If anyone can think of anything please let me know.

Watch the water pump sometimes they will leak seal up for a couple of weeks then leak again. Use a flash light and watch for deposits indicating a leak. Also watch for exhaust smoke in the morning indicating a head gasket leak. Watch along the intake gasket for deposits or wet spots.