Saturday, September 23, 2017 Detailed Auto Topics
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Modern vehicles are not designed to be operated without air conditioning. When the temperature rises, it does not take long to figure out whether the air conditioner is working or not. The extremely important key is why?

proper repair of the air conditioner saves money

Air conditioners fail to cool for a great many reasons. Diagnosis of the problem and proper repair are imperative. Simply adding refrigerant to a system that is not cooling, can do several thousand dollars damage, very quickly. Over-charging a system can destroy a compressor and damage an evaporator core.

electric fans operate at variable speeds to cool the air conditioner condenser

One very common cause for the air conditioner not to cool is a condenser fan that is not working. Most modern vehicles have the two electric fans that cool the radiator and air conditioner condenser. These fans are computer controlled and variable speed.  Even though the fans are turning does not mean they are okay.

The condenser fan may be operating at 50% speed. This cannot be seen with the eye. The head pressure will rise and the air conditioner will quit cooling or shut down. The compressor on such a system is already under great pressure. Adding additional refrigerant can almost instantly destroy the compressor.

Modern air conditioning systems often have a capacity of one pound or less of refrigerant. Adding one additional can to the system may result in 75% or more over-charge. The pressure created can also cause expensive components to fail.

leaking evaporators can be very expensive to replace

The evaporator core is made of very thin aluminum with folded seams. Too much pressure can cause the evaporator core to leak. Replacement of the core very often involves removal of the entire dash and a huge expense.

Another common problem is failure of the actuators under the dash to open the proper doors to allow cooling. The symptoms can range from no cooling, to insufficient cooling or cooling on only one side of the vehicle. Adding refrigerant cannot help and will damage the system.

When an air conditioner is low on refrigerant there is a leak which must be found and corrected

oily residue is compressor lubricant leaking out of the air conditioner system

Leaks create many additional problems. The oily residue around the area of the leak is refrigerant oil. This oil circulates with the refrigerant and lubricates the compressor. Continuing to add refrigerant, will cause the oil to leak out. When this happens the compressor fails and the system is badly contaminated.

Dye can be seen under an ultra violet light and leak can be found

Leaks can be difficult to find and professionals use several techniques. One effective technique is to add fluorescent dye to the system. This dye cannot be seen with the eye alone, but under ultra-violet light glows greenish-yellow. This can be effective in finding slow leaks that take time to show.

Electronic leak detectors are also used. Electronic detectors can detect very tiny traces of refrigerant. Often the system is evacuated and a small amount of R22 added. Pure nitrogen is then used to pressurize the system. R22 is easier to detect than R134A and this makes leaks easier to find.

Do’s and Don’ts of AC repair

 Do have the system repaired as soon as possible. Leaving a system inoperable over the Winter can cause the problem to get much worse.

 Do diagnose the problem and make the proper repair the first time. Re-repair is extremely expensive and sometimes not possible.

 Do not add refrigerant to the system without first diagnosing the problem. Today's small systems are easily overcharged and may sustain considerable damage

Never tighten an air conditioner fitting that is leaking

 Do not attempt to tighten a leak. Air condition lines are sealed with O-rings, never by threads. Tightening the connection will NOT stop a leak and will damage the fittings. Often components that have been over tightened must be replaced.

 Do not add stop leak to the system. Stop leak may be considered a contaminant. Improper blends of refrigerants and sealers will show as contaminated when tested. When this occurs, very expensive removal and disposal procedures have to be followed. The debased contents cannot be recycled, and it is illegal to release it into the atmosphere. Adding substandard refrigerant to an air conditioner may cost the vehicle far more than they expect, for removal and disposal. The costs of this procedure can be shocking.

Air conditioner work is very time intensive and most components are expensive. An improper repair can drastically increase the cost of the inevitable proper repair, that will have to be done. Never trust your air conditioner to anyone other than a true professional and use only the best parts. Proper repair is far less expensive than rework.





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