causes of empty coolant reservoir
If it has coolant in it when your car is completely cold, like after sitting all night, then your cooling system should be full and free of air. If you check the reservoir and find it empty, it is an indication that you have a low coolant level, even if it has some coolant in it when your car is warm. If you find an empty coolant reservoir it is an indication that you have a leak in your cooling system. If this is the case, add BlueDevil Radiator and Block Sealer before you top off your cooling system with new coolant.