if you use a lot of coolant you might have a slight blown head gasket can you smell any coolant at you tail pipe ? I think you low coolant and ticking are 2 different things but the same to a point, as I said before you might have a blown head gasket a small one and your water pump is making the ticking sound because the bearing is going bad. the flow of coolant lubes the pump but the pump works harder when it's low. get a rubber tubing and hold 1 end to your ear and the other end hold in your hand hold it to the lower part of the T/B cover to see if you hear the ticking sound's there. try this in other areas also just make sure you don't get your hand or finger ripped off by the belts and other moving parts.