Hard Start . . . Symptom or Problem?

Hi . . . am new to paying attention to car maintenance and tech, so bear with me. I own a 1999 Chevrolet Cavalier that began starting hard in the morn ing (but turning over nonetheless), a few weeks ago. Brought it to my mechanic, who said the battery was gone, replaced it, said he looked at the alternator and the belt, everything checked out, and the connections were bad, but he replaced those too. Well, it's still starting hard, and the other day, I was driving uphill on a dirt road, and the coolant light came on, but ever so briefly. I checked the connections, and everything associated therewith, to no avail. I am thinking that it is likely the belt itself, which drives the water pump, and could explain both issues. By the way, the light went eright off, and hasn't come on since. I feel like the belt is maladjusted, but I'm wondering if it could be something else, like the ignition coil, etc? The head gasket, water pump, thermostat, cylander connections and coils were replaced in December. Any thoughts anyone has would be appreciated. The car has driven great (97k miles) . . . but I can't seem to find the fix here.

The light you experienced is likely due to the level in the radiator having exposed the electrodes on the sender. Check the level of the coolant in the radiator. There are no sensors to check coolant flow. The difficult starting problem will require some more info. Does it crank hard? Is it slow to start? Ray