Automotive Air Conditioning & Heater Systems Explained

                                 COMPONENTS OF AUTOMOTIVE AIR CONDITIONING










Your air conditioning system is made up of a compressor, a condenser, an evaporator, receiver drier, refrigeration lines, pressure and cycling sensors, and an electric cooling fan for the condenser.




Compressor: This is the heart of your a/c system. The compressor is what takes the refrigerant (the gas) and pressurizes it so it will cool the air. It's run by an engine belt. The compressor also has an electrically operated clutch that turns the compressor on and off as you demand more cool air.


Average cost $359 - $589






Condenser: Located at the front of the engine, next to the radiator. Sometimes the condenser will have its own electric cooling fan, too. The hot, compressed air passes through the condenser reduce the tempurature. As it cools, it becomes a liquid.


Average cost $150 - $350






Evaporator: The evaporator is another little radiator usually located under the dashboard near the heater core. As the super-cool liquid is passed through its tubes, a blower forces air thru it and cools to about 45 degrees in a properly operating system as it exits the vents to the passenger compartment. As it warms up again, the refrigerant starts turning back into a gas.


Average cost depends on the location of the evaporator, if it is located in the engine compartment it will be hundreds less than if it is located under the dash. $175 -$650 evacuate and recharge of A/C system extra $99 utilizing R134 Freon.






Thermal Expansion Valve also known as an Thermal Expansion Block Controls the flow of super-cool refrigerant to the evaporator.


Average cost $100 - $200, evacuate and recharge of A/C system extra $99 utilizing R134 Freon.






Drier or Accumulator: The drier, also known as the receiver-drier, is sort of the safety catch for your system. The compressor is only supposed to compress the gas form of your refrigerant. However, there's always a chance that some liquid could make it back that far. The drier catches this liquid before it can damage your compressor. Since even a small leak or careless installation can introduce water moisture to the system, the drier absorbs this chemically, using what's called a desiccant. The drier also has a filter that catches contamination in the system.


Average cost $99 - $149, evacuate and recharge of A/C system extra $99 utilizing R134 Freon.






A/C hoses and O-rings: Leaks at the a/c hoses and o-rings which seal the hoses are the most common source of freon loss.


Average cost $39 - $99 for o-rings, $89 - $179 for hose replacement, evacuate and recharge of A/C system extra $99 utilizing R134 Freon.






Tip: if your defroster does not automatically engage your air conditioning system, run the A/C system at least 20 minutes a week during the winter. This will keep the o-rings lubricated and compressor healthy when you really need it during the summer months.






HEATER SYSTEM






Main components to the heating: Coolant, Heater Core, Heater Control Valve and Thermostat.






Coolant/Heater Core flush


This service is used as a technique to attempt to clear blockage restricting the heater core. When it is restricted, it will not warm up sufficiently.


Average Cost $59 - $99 depending on vehicle.






Heater Core Replacement






Heater Core


The hot coolant is also used to provide heat to the interior of the vehicle when needed. This is a simple and straight forward system that includes a heater core, which looks like a small version of a radiator, connected to the cooling system with a pair of rubber hoses. One hose brings hot coolant from the water pump to the heater core and the other hose returns the coolant to the top of the engine. There is usually a heater control valve in one of the hoses to block the flow of coolant into the heater core when maximum air conditioning is called for.


A fan, called a blower, draws air through the heater core and directs it through the heater ducts to the interior of the car. Temperature of the heat is regulated by a blend door that mixes cool outside air, or sometimes air conditioned air with the heated air coming through the heater core. This blend door allows you to control the temperature of the air coming into the interior. Other doors allow you to direct the warm air through the ducts on the floor, the defroster ducts at the base of the windshield, and the air conditioning ducts located in the instrument panel.


Ford, Lincoln Jeep, Dodge, Mercedes, BMW, Jaguar are among the most expensive heater cores to replace due to the location of the part. The entire dash requires removal to gain access to the climate control system, including the heater core and A/C evaporator.


Average cost for the Ford, Lincoln, Mercury heater cores is $575, Dodge and Jeep average $675, Mercedes, BMW, Jaguar can cost upwards of $1000 or more. Call for a quote on your particular vehicle.






Heater Control Valve


The heater control valve is the device that controls the flow of hot engine coolant through the heater core. It is usually located in one of the heater hoses to regulate the flow. This valve thus helps to control the heater output as called for by the driver’s control switch.


Average cost for a heater control valve is $59 - $99 plus coolant drain and refill.






Thermostat


During the warm-up period the thermostat valve remains closed. This prevents coolant from flowing from the engine to the radiator. This allows the coolant to warm quickly. As it warms up the valve begins to open. Once the proper running temperature is reached the valve will open so that the coolant and freely flow to the radiator.


If the outside air is especially crisp and cold and the engine has not run for long the heater will blow cold for the driver of the vehicle. The engine needs to heat up so that it can produce heat and allow the thermostat to open and allow coolant to circulate. As the car warms up the heater core will retain heat and continue to let it build up so that when the fan blows over it the air will be warm.


Average Cost $49 - $99 depending on your vehicle, plus coolant.