coolant

No, once the coolant level is good you should never have to add water. However you may have to add water once or twice if there was an air pocket in the cooling system, but no more than that. If it continues, look for a leak. If you don't see a leak, have the engine checked for a blown headgasket.

You better check the water pump or you vally pan gasket if you have any leak. you will see the leak at back of the engine on the floor or you head gasket is not good