Air Conditioning Repair

If Freon is the lifeblood of your air conditioning system the compressor is the heart. It pumps Freon throughout the AC system. The Freon contained in an auto air conditioning system is a gas and liquid combination and is compressed and circulated throughout the air conditioning system. The compressed Freon is pushed through the system under pressure and is passed through different sized metal and rubber hoses and a special valve called an “expansion valve” that causes the gas to expand and contract. The expansion and contraction of the Freon creates a very cold solution.

The cold gas is then pushed through metal lines into the dash area of your vehicle to the evaporator core. This evaporator core looks and acts like a mini radiator, except it has cold Freon circulating inside as opposed to hot antifreeze. A small fan which you operate from the dashboard controls sits in front of the evaporator core and blows air across this cold evaporator which then comes through the vents and cools the cab of your vehicle.

The other objective of the air conditioning system is to remove the hot, humid air from inside the cab of the vehicle. This heat is removed by the Freon with the help of the AC condenser located at the front of the car. The Freon coming back from the evaporator carries the heat from the cab to the condenser. Just like your radiator, the condenser is lightweight aluminum with many internal winding coils. The Freon travels through these coils, in between these coils are small slits or fins that the Freon is forced through. The condenser will have an electric cooling fan mounted in front or behind it to push or pull air through these fins to remove the heat from the Freon.

A few causes of low cooling efficiency or no cooling at all:

• Lack of air flow across the condenser. Make sure the electric cooling fan motor near the condenser is coming on, or in models that are equipped with a fan blade make sure this fan is turning and is turning very fast.

• Low Freon levels. Freon level and pressure should be checked by a Certified Air Conditioning Mechanic. An AC Recharge can be conducted only after your system has been checked and any AC leaks have been repaired.

• Overheating. If the engine is running hot or overheating, it can have a noticeable negative affect on the air conditioning system. Some cars have two electric cooling fans, one for the air conditioning condenser and the other for the radiator. Make sure they are both working properly. Usually at idle on a hot day with the AC on both fans will be on.

• When the vehicle is traveling at freeway speeds, the compressor is pumping the Freon throughout the system much faster and harder than at idle. There is a dramatic increase in air flow across the condenser due to 100 KPH winds, and the engine is usually operating at a cooler, more efficient temperature as well, thus allowing the air conditioning system to operate more efficiently.

Note: An air conditioning system that is somewhat low on Freon can still feel comfortable at freeway speeds due to the added air flow across the condenser which can overcome the effects of slightly low Freon. Periodic air conditioning performance inspections by your mechanic are the best way to keep the system in great shape.