Warning Signs Your Car AC Compressor is Going Bad

Hot. That word is used to describe a lot of things. “Don’t touch the stovetop! It’s …” Or, “My boyfriend (or girlfriend) is …!” “Listen to this hot new recording artist.” “Don’t talk to the boss right now, he’s hot under the collar.” And naturally, we complain how “hot it is outside.” What you do not want that word to reflect is the temperature inside your car. With summer heat pressing in, it is nice to know that you can count on the air conditioner to keep you cool.

But the AC in your car can let you down. And that’s not a pleasant feeling. Sweltering heat that even the open windows can’t ease and a fan blowing nothing but warm, stuffy air is unpleasant. Your AC is not supposed to break down. But sometimes it does.

The AC compressor is one of the problems that could cause your AC to fail. As the main mechanical component in the system, it serves as the heart that pumps refrigerant to and through all of the other AC components. But it does more than pump refrigerant. Driven by the serpentine belt on the engine, the AC compressor creates high pressure in the system by “compressing” the refrigerant to kick off a series of events in the condenser, receiver/drier, and evaporator, all to keep you cool. To do its job effectively, the compressor relies on a special oil for lubrication to keep itself cool, keep sealed, and keep moving. The compressor is the only part of the system that does much moving, so if it stops, so does your AC.

Here are some signs that your AC compressor is about to fail – or has failed already.

AC not as cold as it should be

If you notice that the air coming from the vents with the AC switched on is not as cold as you remember it to be, you could have a problem with the AC compressor. There are other issues related to the AC system that could cause the air to be warmer than normal, but a bad compressor is certainly one option. You can have the air temperature tested to determine if it is indeed higher than it should be.

Noises coming from the engine compartment

All sorts of culprits can be blamed for strange sounds near the engine. A squealing belt, a whining power steering pump, a worn out pulley, brake pads in need of replacement. If, on inspection, you hear chattering, whining, squealing, chirping, or rattling sounds coming from the AC compressor, it is time for AC service. Sometimes the commotion only erupts when you engage the AC switch. Some noises remain constant. Compressor noises result from either a faulty clutch or a seizing shaft. Failure is likely to happen if the compressor oil used for lubrication becomes contaminated (usually with water vapor), is not in sufficient supply, or is of the wrong type.

Damage evident on the AC compressor

Physical damage to the compressor or its clutch could be an indication of an internal problem. Same thing with corrosion. Moisture is the enemy of your car’s AC system, so corrosion on the outside could be an indication of a problem on the inside. Oil leaks will lead to a compressor breakdown. So, any damage – whether something is bent, broken, corroded, or leaking – should be evaluated to make sure your AC system is in working order.

Compressor clutch will not engage

When you switch on the AC, the clutch attached to the pulley on the compressor should engage. Looking at the face of the compressor, the clutch appears as a plate on the front of the pulley. With the AC off, the clutch does not spin. When you turn the AC on, the clutch can make a momentary click and starts spinning with the belt and pulley. If the clutch does not engage, or if it makes a screeching or whining sound when it does, the compressor needs to be serviced.

Connected Concerns

The AC compressor is not the only component that goes bad. Problems with the AC system that are related to the AC compressor include:

• Refrigerant loss: The most common reason the AC does not work is a loss of refrigerant. This is most often due to worn out seals between system components, but could also happen from damage to an AC line or hose. If the refrigerant level gets low, the air will not be as cold in the passenger compartment. If it gets too low, the low pressure switch will keep the compressor from coming on at all. Low refrigerant levels also promote moisture getting into the system – a sure way to kill the whole thing. An AC recharge can refill the system with refrigerant, but if the leak is not located and corrected, and the air evacuated out of the lines, the system will not remain operational
• Refrigerant blockage: This less common problem can happen because of a pinched or damaged AC line or hose. It can also be related to a defective expansion valve or clogged orifice tube
• Worn or broken serpentine belt: If the serpentine belt that drives the compressor pulley is worn, glazed, or cracked, it could prevent the compressor from spinning at the proper speed. If the belt is broken, the compressor will not work at all. Of course, if your serpentine belt breaks, lots of other things will not work either – like the power steering and alternator. But if your car, truck, or SUV has a separate drive belt for the AC compressor, the only system affected would be the AC
• Faulty blower motor: This can be responsible for a loss of AC cooling ability. If the fan does not blow sufficient volume across the evaporator, the result will be insufficient cooling
• Clogged cabin air filter: Related to the blower motor is the cabin air filter that cleans the air as it enters the passenger compartment. Many drivers are not even aware of this maintenance item, therefore it tends to get filled up with all sorts of debris and limits the airflow through the vent
• Blown fuse: Believe it or not, a simple fuse could be the cause of inop AC. But don’t be fooled. Simply changing a fuse might get the AC up and running again, but the result may be only temporary if the cause of the blown fuse is not identified.

Keep your eyes and ears tuned in to these signs of AC compressor failure and related problems. If you do notice any of the above, understand that most of these concerns are not do-it-yourself repairs. While you are driving your hot new car with its hot red paint job and jamming some red hot tunes, make sure your AC is keeping you and your passengers cool in the summer heat. Make sure to head in to a trusted repair shop for auto AC service.

Hogan & Sons Tire and Auto | Author: Mike Ales | Copyright