First, what is the primary function of a car’s A/C compressor? The A/C compressor is the core component of your car’s air conditioning system. Driven by the engine’s drive belt, it pressurizes the refrigerant, turning it into a high-pressure gas. This process is essential for the refrigerant to circulate through the A/C system, absorb heat from the cabin, and ultimately provide cool air. In essence, the compressor is a pump that facilitates the refrigerant’s temperature-changing capabilities. Due to normal wear and tear, extended service, or neglect, various issues can develop with your vehicle’s A/C compressor.
This podcast provides information about what to look for to determine if your A/C compress is failing. The podcast focus on the functionality, symptoms of failure, diagnosis, and replacement of the A/C compressor, rather than a chronological series of events related to a specific incident.
- [0:00] Start by going over the warning signs that indicate a failing AC compressor
- [2:40] The air conditioning system blows less cold air or only warm air.
- [2:50] Strange noises (squealing, chattering, whining, rattling, knocking, chirping) emanate from the engine compartment, especially when the AC is engaged.
- [4:20] Drive belt failure could lead to other major problems – alternator, power steering, ….
- [6:15] The compressor clutch fails to engage or disengage properly, or makes strange noises when doing so (clicking, grinding), or get stuck.
- [7:50] Refrigerant leaks occur (a common issue), potentially due to over-compression or failing seals.
- [9:15] Internal failure of the compressor leads to contamination of the AC system with metal debris.
- [9:45] How to address the debris issue
- [10:10] Compressor pulley could fail
- [11:08] The financial hit – the cost of the repair – big range depending on the vehicle
- [12:14] Other components need to be replaced as part of the repair
- [13:55] Alternative things to think about – other options worth considering
- [15:15] Preventative measures to take to keep your A/C heathy [important]
- [17:20] Finding the best deals to get your vehicle serviced
- [18:40] Key takeaways about A/C compressors – early detection is key
Once a faulty compressor is suspected, a decision needs to be made regarding repair or replacement. Rebuilding compressors is uncommon; replacement is usually the recommended option. After replacement, the AC system should function correctly, blowing cold air. Regular use and maintenance can help prolong the life of the new compressor. A car’s AC compressor typically lasts between 10 and 12 years or 150,000 to 200,000 miles, although this can vary based on usage and maintenance.
Helpful Definitions
- A/C Compressor: The component in the air conditioning system responsible for compressing the refrigerant, increasing its pressure and temperature, and circulating it through the system.
- Refrigerant: A chemical substance used in the A/C system that absorbs and releases heat as it changes state from liquid to gas and back, providing the cooling effect.
- Drive Belt: A belt driven by the engine that transfers mechanical power to various components, including the A/C compressor pulley.
- Clutch (A/C Compressor): An electromagnetic mechanism on traditional compressors that engages and disengages the compressor from the drive belt pulley, allowing the compressor to turn on and off as needed.
- Positive Displacement Compressor: A traditional type of compressor that moves a fixed volume of refrigerant with each rotation of its internal components (usually pistons).
- Variable Displacement Compressor: A more modern type of compressor that can adjust the amount of refrigerant it pumps based on the cooling demand, often using an internal swashplate mechanism.
- Refrigerant Leak: The escape of refrigerant from the sealed A/C system, often due to damaged seals, hoses, or components. Refrigerant leaks can reduce cooling performance and eventually prevent the compressor from functioning.
- Contamination (A/C System): The presence of foreign materials, such as metal debris from a failing compressor, within the A/C system. Contamination can damage other components and hinder system performance.
- Manifold Gauges: A diagnostic tool used by technicians to measure the pressure on the high and low sides of the A/C system, helping to identify various problems, including compressor issues.
- Receiver Drier/Accumulator: A component in the A/C system that removes moisture and filters debris from the refrigerant, often recommended for replacement when the compressor is changed.
- Expansion Valve/Orifice Tube: A metering device in the A/C system that controls the flow of refrigerant into the evaporator, also often recommended for replacement with the compressor.
- Refrigerant Oil: A special oil that circulates with the refrigerant to lubricate the internal components of the A/C compressor.
- Seized Compressor: A condition where the internal mechanical parts of the compressor have locked up and can no longer rotate.
- Compressor Clutch Failure: A malfunction of the electromagnetic clutch that prevents it from engaging or disengaging properly, thus stopping the compressor from running or causing it to run constantly.
- Evacuate (A/C System): The process of removing all refrigerant and air from the A/C system using a vacuum pump, typically done before replacing components or recharging the system.
- Recharge (A/C System): The process of adding the correct amount and type of refrigerant back into the evacuated A/C system.
