Air Conditioner Compressors & Clutches

Signs of a Bad Car A/C Compressor

There is nothing worse on a hot day than getting into your vehicle, turning on the air conditioning and (even after minutes of running) hot air pumps out of the vents. The entire purpose of running centralized air is to circulate cool, fresh air around the cabin. If your A/C is set to cold, but warm air is emitting when turned on, then you might have an auto A/C compressor that is failing. Even if the temperature of air coming out of the vents is fluctuating, it is possibly time for a A/C compressor replacement.

Air conditioning compressors for cars, trucks, vans and SUVs can fail due to age, wear or neglect. So, exactly what are the signs of a bad car A/C compressor? Here is some advice from the NAPA experts for diagnosing automotive HVAC issues. Start by visually inspecting your A/C compressor and clutch for rust and physical damage. A malfunctioning clutch might cause the belt that drives the A/C compressor in a car to wear down faster than normal, which can lead to even more damage and costly repairs. If the belt is torn, dirty or loose, the performance of your HVAC is compromised, which should trigger an alert like a dashboard warning light.

Leaking oil is another visual clue that there is an A/C compressor issue. Automotive compressors require oil to run smoothly and efficiently. Running your A/C when the oil is low can cause premature failure of this critical part. Check for pooled liquid under the vehicle or moisture around the compressor and clutch.

Finally, one of the most apparent signs of a failing A/C compressor is squealing coming from under the hood. If you notice loud noise when the compressor switches on, it's a sign your A/C clutch is bad. Your clutch should remain unobstructed. If your clutch is hard to turn (seized) or emits a grinding noise, make an appointment with the nearest NAPA AutoCare Center before the entire compressor unit goes bad.

How Does an A/C Compressor Work in a Car?

The air conditioner compressor is the center of a vehicle's air conditioning system. And, your A/C compressor clutch is one of the most important parts of the entire HVAC assembly. The A/C compressor with clutch (located near the other belt-driven components under your hood) pumps pressurized refrigerant fluid through the system to provide cool, controlled air. A fine oil mist circulates with the refrigerant, lubricating moving parts and sealing rubber hoses.

This critical automotive part compresses refrigerant from a gaseous state to a fluid state, then circulates it to a condenser coil, which removes heat from the refrigerant. Once the liquid turns back into a gas, the accumulator removes moisture from the refrigerant, which flows to an evaporator where it blows cold, dry air into the cabin. Today, most automotive manufacturers use a compact, efficient, axial-style compressor, which utilizes a swash plate to move multiple pistons up and down to compress the refrigerant.

Conventional combustion-engine vehicles (non-EVs) use belt-driven compressors, which can wear down, crack or even snap. Make sure to check the integrity of your A/C compressor and compressor belt. The A/C clutch drives the belt that connects the A/C compressor to the engine pulley. Without a properly functioning clutch and belt, the compressor has no power. On hybrid and electric vehicles, the air conditioning compressor is powered directly by a high-voltage electric motor with some models getting as high as 400 volts.

Getting a Car A/C Compressor Replacement

Replacing an air conditioner compressor in your car is one of the most complex and labor-intensive repair projects a mechanic can perform. A/C issues require in-depth diagnostics, extensive disassembly and specialized tools. For instance, technicians must use a recovery machine to extract refrigerant and protect the atmosphere. On reassembly, it is critical to ensure the proper charge of refrigerant and oil for optimal performance.

Before you start shopping for a replacement A/C compressor, you might want to know how long a car A/C compressor is supposed to last. It really depends on how much you use your A/C, but a realistic range is 8 to 12 years.

When it comes to A/C replacement compressors, The NAPA Network has you covered. Check out our new A/C compressor clutch shim kits, compressor brackets, clutch coils, clutch mounting kits, guard screens, compressor manifolds and valve plates. Also, take advantage of NAPA Rewards and get One Point for every $1 you spend. Sign up today and save!