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Your car’s air conditioning compressor does just that – it compresses refrigerant and keeps it moving through the entire AC system. It’s a crucial part of what makes your car’s AC work, and if you have AC trouble on a hot day, you’ll want to know more what it does, and how to replace it should it go bad.

How Does the AC Compressor Work?

The air conditioning compressor is powered by mechanical energy from the drive belt on your engine, and compresses R134a (or other refrigerants). It is essentially a pump, drawing in refrigerant, compressing it, and pumping it out. This pressurized refrigerant then makes its way through the AC system, where different components take the refrigerant from a gas to a liquid, which cools it rapidly, where it’s cold state does its job to keep the vehicle’s cabin interior cool.

The compressor contains several parts which can fail. One of the most common of these parts which can have problems is the compressor clutch, which engages or disengages to turn on or off the compressor as needed. If this part breaks while engaged, the compressor will always be running. If it breaks while disengaged, it won’t run at all. Other times, the bearings located within the clutch can also fail, causing noise. Compressors can also have bad seals, causing leaks, or the mechanical internals can simply fail due to wear, age, or lack of proper oil.

If your compressor isn’t working, you’ll know it because it’s one of many reasons your AC could be non-functioning, meaning a broken compressor will result in your vents blowing hot air. It’s important to understand that your vehicle’s AC not working could be caused by a number of issues – anywhere from just being low on refrigerant, a bad cycling switch or relay, or a faulty compressor. That’s why it’s important to correctly diagnose what’s wrong with your AC system before you start replacing parts.

How Much Does an AC Compressor Replacement Cost?

An AC compressor change can be complex based on the parts needed to do the repair properly. This can vary quite a bit based on the vehicle you drive, and where the compressor is situated on the engine. Besides the compressor, there are other parts that should always be replaced at the same time the compressor is being serviced.

It’s also important to note, that if your compressor suffered internal failure, the entire AC system’s lines and components will need to be properly flushed out of contaminants. Failure to do this is a guaranteed-ticket for another failed compressor, as these same contaminants will damage the new one.

In general, keep in mind the following parts, which should be changed when doing a compressor:

If you are mechanically-inclined, you can potentially avoid all labor costs by replacing the compressor yourself. Just be sure that you research the other components listed above, and their replacement as well. It’s worth noting that this job is somewhat complicated, and probably not a good choice for new DIYers. You’ll need some specialized tools like a vacuum pump and a set of manifold gauges to do the job right. 

If your AC clutch has failed, these can many times be replaced on their own without swapping the compressor but require special tools and procedures to swap out properly. Many times, the entire compressor is more cost-effective to replace.

Generally speaking, to have a shop properly change an AC compressor and related components, flush, and re-fill the AC system will run between $750 – 1500.00. Depending on the model and cost of the parts in general, this cost could be even higher. 

To DIY this project, the cost of parts, flush, and refrigerant will generally run between $350.00 – 650.00. Keep in mind that when dealing with air conditioning, having the system properly charged by a professional is a good practice to ensure the system is properly charged and functioning. Check out our list of preferred shops in your area that specialize in AC.

How Long Does an AC Compressor Last?

An AC compressor is not a maintenance part which you are expected to regularly replace on some interval. The compressor only needs to be replaced if it fails. They can last the lifetime of the car, but generally a compressor’s life span is around 10-12 years and 150 to 200K miles.

Is it Safe to Drive with a Bad AC Compressor?

Most of the time, yes. It’ll be hot, but your car will run and still be safe to drive. The scenario when you should not drive a car with a bad AC compressor is if the clutch or pulley is damaged, as this could break or de-route the serpentine belt and leave you stranded. 

If you suspect a bad clutch bearing or pulley, locate the compressor while the engine is running and observe the front pulley/clutch where the belt runs. If you hear any grinding or noises coming from this area, this is a concern. Stop the engine, and if possible, check the front of the pulley for any side to side motion, slop, or play, paying caution to the fact that the engine is hot.

If you hear noise, or observe any slop or play in this pulley, the clutch is more than likely bad. If the clutch’s pulley is still functioning properly, driving your vehicle is safe until replacement or AC diagnosis is performed.

Now that you have a general idea of what to expect, consider getting an estimate that is specific to your vehicle by contacting one of our preferred shops near you. Or, if you’re planning on going the DIY-route, find all the parts and tools on AutoZone.com, or at one of our 6,000+ stores! 

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Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

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