How to Repair an Auto Air Conditioner
Fixing an air conditioner in a car can be a major undertaking, or it can be as simple as recharging the freon in the system. Troubleshooting car problems can be an easy fix most of the time if you have the right tools, the right knowledge, and the right problem (in that some problems simply are laborious fixes)
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Instructions
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Know your parts
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Diagnose which part of the air conditioning (AC) system is going awry. There are five major parts of the AC system. The compressor circulates and compresses the coolant. (The coolant carries the heat in the system, and is usually R-134 on most newer models). The condenser changes the phase of the coolant and removes the heat from the coolant as well. The expansion valve regulates the pressure of the coolant. The evaporator transfers heat from your car to the coolant. The dryer acts as a filter for the coolant by removing moisture and contaminants.
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Test your hoses for leaks. Make a simple solution of liquid detergent in a spray bottle and soak the AC hoses and connections while the system is running. The coolant must be under pressure to reveal any leaks. If you see any bubbles, you have found your leak. Only when you are sure that there are not any leaks can you add coolant to your system. It is illegal to release freon gas into the atmosphere.
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Clear out the condensing coils. Debris can sometimes gather around the condensing coils, preventing heat from being expelled from the AC system. Also look around for any broken wires, burned-out fuses, bad switches, broken fan belt, or seals that have broken around the compressor.
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Top off the coolant. If the system has some coolness to the touch, but not a lot, perhaps it is only missing some coolant. If this is the case and you have already checked for leaks, add some coolant. This should raise the pressure inside the AC system and will increase its ability to perform the cooling operation.
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Flush your system. Access the expansion valve and the evaporator. When you remove the evaporator, clean it with water and light scrubbing, being careful not to get any water in the pipes that contain the freon. Use an AC flush kit to clean out the freon pipes, followed by compressed air.
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Check your compressor. If it is leaking coolant or making clicking noises, it will need a replacement. Also check to see if the clutch is engaging while the AC is running. If you are replacing it, add oil to the suction side and rotate the clutch several times to prime the oil moving through the system. Tighten the four bolts to the compressor in a circular manner so that the compressor case does not become warped. Last, rub some oil on the freon pipe fittings for a good fit and preventing dry rot.
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Tips & Warnings
If you are at all uncertain about the process of working on cars, either take your car to a professional or find a friend who can help.
If you are attempting to change your AC system from an old R12 coolant to R134, be careful and follow the directions explicitly. Wear safety protection on limbs, hands, and eyes. Be careful not to mix the two coolants. Mechanics often refer to these conversion kits as "Black Death Kits."
Never connect recharging kits to the high pressure side of the system.
