Bad heater core?
Check your cabin air filter.
How To Find & Fix Coolant Leaks http://www.aa1car.com/library/coolant_leaks.htm
Probably the thermostat is sticking.
How To Find & Fix Coolant Leaks http://www.aa1car.com/library/coolant_leaks.htm
The coolant leaks out.
It leaks coolant.
Only if the sensor is malfunctioning.
If it had no leaks it would not be loosing coolant. So therefore it does have a leak. It can be leaking in a spot where the coolant burns away before dripping on the ground. Also a blown head gasket is a possibility. Look for coolant in the oil. A heater core can leak. Do you smell coolant inside the car or are the windows fogging up or developing a film. You need to have a pressure test run on the cooling system and find this leak.
Heater core leaks, depending on severity, may present with several symptoms which include fogging on inside ofwindshield with coolant residue (smears instead of evaporates when wiped), coolant or antifreeze smell in vehicle and otherwise unexplained loss of coolant from radiator reservoir.
Check the valve cover gasket, if not that you may have a warped head.
yes, especially if the leak is causing coolant to leak, you can run out of coolant. then overheat.
If coolant leaks onto an engine it will cause no damage unless it leaks onto the alternator or into a wire harness connector of some sort. It is best to clean up leaked coolant as much as possible. It will smell a little when the motor is started. Leaked coolant on the ground is a danger to animals and children as it has a sweet smell but is very toxic.