This is the second section of a three part article explaining about a vehicle’s air conditioning system, how it works and how repairs are generally performed. If your trusted repair facility performs an air conditioning inspection or diagnosis and determines that your vehicle might be low on freon/refrigerant, it is most likely that you have developed a leak somewhere in the a/c system. Since freon/refrigerant is in a gaseous state when it leaves its sealed containment, it can at times be a little difficult to find the origin of that leak.

The standard practice is to add a fluorescent dye into the air conditioning system along with enough freon/refrigerant to operate the air conditioning system to fully pressurized state and circulate the dye throughout the system. Then a technician uses a special UV light and glasses to inspect all the lines, connections and components of the air conditioning system for any dye leaking from them. A pinhole leak can be very difficult to identify since it is such a slow leak, and it may take a period of time for the a/c system to operate before it can be identified. The a/c system may seem to have lost it’s cooling efficiency suddenly, but that may be because the system pressure has finally lost enough
pressure and capacity, that the controls of the a/c system have shut off the system.

During the diagnosis and leak detection portion of an air conditioning system, a technician or repair facility may recommend either topping off the system with air conditioning freon/refrigerant or to perform a complete evacuate and recharge of the system when the fluorescent dye is added. Both of these options can enable the a/c system to operate and provide cool air again to the cabin of the vehicle for a period of time. But keep in mind neither service involves a permanent repair or fix of the air conditioning system if it is leaking.

A top-off of you’re a/c system involves simply adding some freon/refrigerant into the vehicle’s a/c system. This is a less expensive procedure than a complete evacuation and recharge, but a technician has no way of determining precisely how much freon/refrigerant is currently in the a/c system and has to rely on his experience to guess at how much freon/refrigerant to add to the system. The downside of this procedure is that overcharging or operating a system in an undercharged state can cause damage to the air conditioning compressor. An evacuation and recharge service includes removing whatever remaining freon/refrigerant is in your vehicle, along with any air and moisture into a recycling machine. Then when the system is recharged with freon/refrigerant the technician will be able to use the precise amount of refrigerant recommended by the vehicle’s manufacturer. This is again a more expensive procedure but is much more accurate.

To properly fix the a/c system for longevity, all of the components that show evidence of leaking need to be repaired or replaced. The system needs any remaining freon/refrigerant evacuated from the system before the work can be performed and recharged with the proper amount of refrigerant and oil upon completion to work properly. During our next article we will cover some information about the costs of air conditioning repairs. Steve and Karen Johnston are owners of All About Automotive in Historic Downtown Gresham. If you have questions or comments, call them at 503-465-2926 or email them at [email protected].

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