bad heater core
There is a drain on the outside firewall that is clogged.
You are experiencing the classic symptom of a leaking heater core. They aren't cheap. Some stop-leak in the radiator might get you through the interim if you need to budget it.
This would be caused by a leaking heater core, or a leak in the plumbing associated with it.
If its inside the cab at the firewall, its probably your heater core which is located on the passenger side under the dash. This repair is usually not much fun. If its leaking in the engine compartment near the firewall, its probably a heater hose that is failing. This is an easy repair
Be more informative on "over heats". Is it being driven along time before it over heats? Is the guage showing hot but not boiling out the radiator, is there steam coming from under the hood, is there a sign of leaking under the passenger side dash or under the firewall on the ground, have you had the thermostate replaced, is the water pump leaking?
The ac drain is plugged. The drain hose is on the firewall on the lower passenger side. ...that, or your heater core is leaking.
The radiator will need to be replaced. Sometimes, it may seem that the radiator itself is leaking but it could be the radiator "hose" that is leaking. In this case, the radiator hose needs to be replaced and clamped tightly.
The heater core (a small radiator for your heat) is leaking, I would suggest a new heater core as they are about as cheep to replace as they are to repair.
The heater core is leaking. The whole dash has to come out to fix it. Even master mechanics dread a heater core repair. Try some alumapowder in the radiator. Try some of this, it really works and stops leaks without plugging up the radiator.
Check radiator hose, leaking water pump, look for hole in radiator, leaking coolant bottle or leaking seals.
foggy windows on passenger side.... smell of antifreeze in car... lost of radiator fluid.. lose of power..
You have a leaking heater core. you can try radiator sealer but that may only work for a short time.