Basic maintenance is about the same as the cooling system; clean leaves and bugs from the front of the car. Good air flow is very important. It seems to be a good idea to use the air conditioner in the winter to help defrost the windshield. Use the air conditioner at least once per week if possible. Some loss of freon after a few years may be "normal". Seals wear and lose pliability after being subjected to heat and vibration. Under hood temperatures "cook" hoses and coupling seals. We suggest an air conditioning checkup at the first sign of diminished cooling.
Anatomy of an automotive air conditioner
The "heart" of the system, pumps refrigerant through the air conditioning system. Refrigerant (freon) is a hot gas when it leaves the compressor and must be cooled and allowed to "condense" to a liquid state. The compressor starts the "process" over by compressing the freon gas and sending it to the condenser. The freon gas has removed heat from inside the vehicle. The condenser will give up this heat to the air.
The hot gaseous freon goes from the compressor to the condenser. The condenser looks similar to, and is mounted in front of the radiator. Air flowing through the condenser cools the freon. The freon gives up heat to the air and changes to the liquid state. From there it flows to the receiver-drier.
Receiver / drier
The liquid freon is "stored" in the receiver-drier for a time until it flows to the expansion valve. While being stored, the freon comes in contact with a desiccant material that removes moisture that may be in the system. Freon must be dry. Water and freon molecules can combine to form acids that do damage to the system.
The expansion valve controls the amount of freon flowing into the evaporator. Like a water valve, it controls the flow of liquid. The amount of freon allowed to enter controls the temperature in the evaporator.
The evaporator looks somewhat like a small radiator. Liquid freon, under high pressure, is metered into the evaporator (which is at a much lower pressure) and allowed to change from a liquid back to the gaseous state. The blower motor directs the air inside the cab across the evaporator. Heat is removed from this air when this change of state occurs, cooling the inside of the vehicle.