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Common Automotive Air Conditioning Problems in Bel Air MD

Posted by tom zoebelein on Wed, Jun 24, 2015 @ 10:25 AM

Hot days are ahead for all drivers in Bel Air MD and surrounding areas.
Hot days equal hot cars, and an increased reliance on your car’s AC.HotCar

For some Bel Air Drivers, the summer will be trouble free, and for others like me, we are struggling with air conditioners in our cars that either blow hot air, or only work for a few minutes and then shut off.

When diagnosing your poorly performing air conditioner, the most likely cause is no refrigerant in the system. If the refrigerant has escaped past a faulty compressor or leaky O-ring seal, perhaps leaked out of a pinhole in the evaporator or condenser, or seeped out through a leaky hose, the leak needs to be identified and repaired before the system is recharged.

On many cars, the compressor will not turn on if the refrigerant is low because the "low pressure safety switch" prevents the compressor clutch from engaging if system pressure is low. This protects the compressor from possible damage caused by a lack of lubrication. This is an issue that I am having, the AC will limp along sort of cooling the car at low temps like 75-85 degrees, but when it hits in the 90’s or above, it shuts off after a few minutes.

One of the first things you should have checked by a competent Bel Air MD automotive mechanic, is compressor engagement. If the compressors magnetic clutch is not engaging when the A/C is turned on, the problem may be a blown fuse or a wiring problem. If the fuse is blown, replacing it may restore cooling temporarily. But the underlying reason for the fuse blowing in the first place needs to be identified and corrected to prevent the same thing from happening again.

If the magnetic clutch is receiving voltage but is not engaging the compressor, the clutch is defective and needs to be replaced. If there is any evidence of leakage around the compressor shaft seal, the seal should also be replaced.

If the clutch works but fails to turn the compressor (often identified by a squealing belt) the compressor has seized and needs to be replaced.

Compressor failures are usually the result of loss of lubrication, which in turn may be due to low refrigerant in the system, a blockage (such as a plugged orifice tube which prevents refrigerant and oil from circulating to the compressor), loss of lubricant due to leaks or improper service procedures, or use of the wrong type of lubricant.

R-12 systems require mineral oil while R-134a systems require various types of PAG oil or POE oil. Using mineral oil in a newer R-134a system can cause serious lubrication problems as can using the wrong grade of PAG oil. Always follow the vehicle or lubricant manufacturers compressor oil recommendations. This is again why Air Conditioning repairs are best left to ASE certified auto mechanics.

The next thing your Bel Air mechanic should check when troubleshooting a no cooling problem, is system pressure. To check for this, you need a set of A/C service gauges. Your mechanic will attach their service gauges to the high and low service fittings. If both the high and low side pressure gauges read low, the system is low and needs recharging. But before any refrigerant is added, your mechanic must check for leaks to find out where the refrigerant is going.

If you suspect that you have a seized AC compressor, or a low refrigerant situation with your car, take it to an ASE certified Bel Air auto mechanic, Such as our shop at Ward Automotive, and get your car’s AC system serviced properly before more damage is done.

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