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Most Common Causes of Auto Air Conditioning Failure

The Most Common Causes of Auto Air Conditioning Failure

Refrigerant Leaks are the #1 cause of auto air conditioning failures

Refrigerant is responsible for cooling the air within the system, and when a leaks occur, the system’s efficiency drops significantly. Leaks can develop from various points, such as rubber seals, hoses, connections, or even the condenser itself. Over time, seals can deteriorate, leading to gradual refrigerant loss. Detecting and repairing these leaks promptly is crucial to maintaining a properly functioning air conditioning system.

When a refrigerant leak occurs, oil leaks out with the refrigerant. From that point on, the system not only cools poorly, but the compressor starts to wear due to the lack of oil. If you add more refrigerant from an AC recharge kit, you might get more cooling, but unless you replace the oil you lost, your system is headed for an early grave.

Also, if the refrigerant leaks out in extremely cold weather, chance are high that air will enter the system. No auto AC system can work properly with air in it.

Compressor Issues are the 2nd leading cause of auto AC failure

The compressor is often referred to as the heart of the air conditioning system. It pressurizes the refrigerant and circulates it through the system. Compressor failure can stem from various issues, the most important being lack of lubrication due to a refrigerant leak. But an AC compressor can also fail due to a clutch issue, pulley bearing, front shaft seal leak, bad flow valve or just plain wear and tear.

As a compressor wears due to lack of lubrication, the metallic wear particles spread through the system. Any air in the system causes the particles to oxidize and turn black, which is why this type of compressor failure is referred to as black death.

image of inside of ac compressor showing black death

ac compressor black death

Moisture in the system is the 3rd most common cause of auto AC problems

Any time air enters the system, it carries moisture in as well. Moisture reacts with the refrigerant and oil to form an acidic emulsion that not only coats the inside of the condenser and evaporator, but also starves the compressor for lubrication.

Moisture can cause the expansion valve to freeze shut, preventing cooling and it the emulsion sludge it creates can clog the screen on orifice tube systems.

AC orifice tube

New and clogged AC orifice tube. Clogged tube shows evidence of “Black Death.”

Clogged or Dirty Condenser or Non-functioning radiator fans are the 4th leading cause of auto AC failure

The condenser is responsible for releasing heat from the refrigerant, allowing it to cool down and flow back into the cabin. Over time, dirt, debris, and contaminants can accumulate on the condenser’s fins, hindering its heat exchange efficiency. A clogged or dirty condenser can result in reduced cooling performance and cause the system to struggle in maintaining the desired temperature. Also, if the radiator fans aren’t operating properly, pressure in the condenser will rise to the point where the high pressure switch shuts off the compressor.

Electrical Malfunctions cause AC issues

Modern auto air conditioning systems are complex and reliant on electronic components. Electrical malfunctions, such as blown fuses, faulty sensors, relays or wiring problems, can disrupt the functioning of the system. For instance, a malfunctioning temperature sensor might inaccurately gauge the cabin temperature, causing the system to behave erratically.

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Posted on by Rick Muscoplat

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