How to Diagnose Common Auto AC Repair Problems – From Intermittent Cooling to Bad AC Odors

Normally troubleshooting your car’s AC is best left to professional technicians and mechanics, especially for modern auto air conditioning systems.

However, for minor auto AC issues you can be spared from frequent car check-ups and repairs if you know how to diagnose your car’s more common air cooling problems. Here are some of the more common auto AC repair problems you may encounter:

AC Is Not Cool Enough

There are several probable causes for this problem. Some are as follows:

1. Low refrigerant level

Under most circumstances, your AC will not easily run out of refrigerant. If you do find that your AC is low on refrigerant, be sure to inspect it for leaks and breaks before recharging your system.

2. Blown fuse or wiring problem

Power on your AC and if the clutch does not engage, you may have a blown fuse or wiring problem. Replacing the fuse can temporarily correct the problem but should be further checked to know the reason why the fuse blew to avoid the same problem in the future.

3. Defective magnetic clutch

The magnetic clutch could be considered defective if it receives input voltage but is not powering the compressor. This should be immediately examined and replaced if necessary.

4. Faulty compressor

A squeaking belt can be a sign of faulty compressor. In addition, the compressor should be replaced if the clutch is working but the compressor fails to turn on.

Leaking Refrigerant

Leaks are probably the most common problem in auto AC repairs. Leaks are usually found in hose connections, seals, and through microscopic pores of the hose. Modern systems induce fewer leaks than older systems, but slight changes in the refrigerant level in newer units can severely affect its cooling performance.

Visual indications like oil stains and wet spots are less obvious for R134A systems because its lubricant is not as oily as opposed to older R12 systems. Various methods can be used to determine the leak in an AC system.

A special dye with mixed refrigerant in a pressurized can is sometimes added to the system. Electronic leak detectors can also be used, or the primitive style of soaking or spraying the hose with soap and water and following the bubbles is still being practiced by modern technicians. Leaks should be repaired by replacing the O-rings, seals, and hoses before recharging your AC.

Intermittent Cooling

This problem is easily noticed when you have alternate blowing of warm and cool air. Its usual cause is the presence of air and moisture in the system. Auto AC repairs for intermittent cooling is normally done by purging air and moisture from your AC by using a vacuum pump.

Intermittent cooling can also be caused by electrical faults like:

o Defective relays and switches

o Compressor clutch

o Control module

o Temperature sensor

AC Noise

Typical causes of noise in an air conditioning system are:

o Sign of compressor problem

o Cross-contaminated refrigerant

o Wrong type of lubricant

o Rattling of hoses and other AC parts

Auto AC repairs for noise can be as simple as tidying your hose layout. If you are sure that the noise is not caused by a rattling hose, you can try to replace the lubricant and verify if your compressor is still functional.

Bad AC Odor

A system which blows air that smells like a foul gym is typically caused by bacteria in the evaporator. Aside from the bad odor, bacteria in the air conditioning systems can also cause health problems. One remedy for this bad odor is to spray disinfectant in the evaporator or through the blower ducts.

If the air blown by your unit smells like gasoline or oil, you might need to consult professional help.

Take care when trying to diagnose or repair your own auto AC problems. When in doubt, always consult with your automotive professional.