Ford: Ford Cooling Systems, water coolant, heater core

Question
I have a 99 Taurus and a 93 Aerostar. Both at 58K.
They do not overheat, but they both are giving off a coolant smell that coming thru the vents and I'm replacing water/coolant weekly. Not alot, but topping off at least close to 1/2 a quart to a quart. The only fluids I see on the ground is the normal overflow. No smoking of anykind from the exhaust. I'm thinking that perhaps the system is just really dirty. If it needs cleaning, what would you suggest on how to do it? Thank you.

Answer
If your getting a coolant smell threw the vents, then you have a leaking heater core. Turn your heater on, and smell around,I can almost bet you will smell coolant. You will need to change the heater core. I would suggest getting a repair manual, to help you threw the repairs on this..