Keep your cool this summer by understanding what causes A/C Compressor failure

10 August 2020 | Article

With the weather across Europe heating up and more people venturing out for long drives, vehicle air conditioning (A/C) systems are set to be switched on after long periods dormant. However, like any car component, the air conditioning system can experience troubles, leaving motorists at the mercy of an uncomfortably warm cabin interior. Often, when the A/C system experiences issues, it is down to a failed Air Conditioning Compressor. Understanding how to identify signs of A/C Compressor failure and having the parts and knowledge required to fit replacements is essential for technicians at this time of year.

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What is an A/C Compressor?

The A/C Compressor is an integral part of the vehicle air conditioning system. When the A/C system is switched on, the compressor gets to work, pumping gaseous refrigerant through the condenser at high pressure, where it changes from a gas to a liquid. The dryer then removes any contaminants and moisture from the refrigerant, moving it through the expansion valve. Finally, the refrigerant moves to the evaporator where it cools the air.

A fully functioning A/C Compressor is critical for the air-conditioning system to provide peak performance. With a damaged or faulty A/C Compressor, the chain of events described above simply cannot happen.

Why do Air Conditioning Compressors fail in the summer?

It’s not always the case that A/C Compressors fail at this time of year, but it is during the summer months that any failures become apparent, as A/C systems are switched on after a long time dormant.

Like any vehicle component, A/C Compressors have an operating life but it can be difficult to determine when this is, since people drive differently on varying terrains and in all-season conditions. Mileage also plays a part. Increased mileage can lead to an increase in the wear and tear of all car parts, particularly the A/C Compressor. It’s often the case that the first sign of a failed Compressor is a decrease in cool air emanating from the A/C system.

Regular air conditioning servicing can prolong the life of the A/C Compressor, as can running the A/C system in the correct way. In most cars, Air Conditioning systems are used for heating and cooling as well as ventilation. When the A/C system is not used for either purpose for long periods of time, failure can occur. Therefore, motorists ought to be advised to run the A/C system for more than 10 minutes each month to ensure efficient all-year operation.

Another sign of failure is noise coming from the A/C Compressor, or some scraping noise coming from the A/C system, which sometimes can be heard inside the vehicle. This can imply an insufficient amount of refrigerant – both of which are key signs of (future) component failure.

What causes A/C Compressor failure?

There are several reasons why an A/C Compressor may fail, ranging from lack of maintenance to seasonal driving conditions. Below are some of the most common causes of A/C Compressor failure…

Improper lubrication

All mechanical systems within a vehicle require the right lubrication and Compressors are no different. Any time metal parts rotate or slide, they are prone to wear and excessive heat buildup. Lubrication helps to ensure good functionality and a long life.

Improper lubrication - or none at all - will strain the air conditioning system and cause the A/C Compressor to fail. A full replacement can be expensive so advising customers to opt for frequent air conditioning servicing, and keep A/C Compressor lubrication to its best, will help ensure they don’t end up with unexpected repair costs.

Dirty or damaged coils

Road surfaces during summer are dusty and can be full of small debris, with lots of tiny particles floating in the air. When these particles collect on condenser coils, the air conditioning system will be unable to expel the levels of heat required from the system and will cause high thermal loads on the A/C Compressor to try and cool the cabin. This means that A/C Compressors can overheat during summer months, which results in inevitable A/C Compressor failure and the need for a full replacement.

Debris inside the system

Debris inside an A/C system can be caused by rubber particles of the discharge hose. Depending on the quality of the rubber hoses used, overtime, the rubber starts to deteriorate and small rubber particles comes loose and float through the A/C system. This can cause blockages in the A/C system. In the worst case it will cause A/C Compressor failure, as this blockage prevents the flow of refrigerant and oil mix, back to the A/C Compressor. 

Low or incorrect refrigerant

R134a is the refrigerant required to make the A/C system blow cold air in most cars on the road today. Since January 2017, all new produced vehicles within the EU are equipped with refrigerant type R1234yf because of environmental reasons. The refrigerant amount in a vehicle A/C system should be maintained at a constant level. When there is an insufficient amount of refrigerant in the A/C System, the thermal load on the A/C Compressor will become higher and finally can cause the A/C Compressor to fail. 

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The DENSO difference

DENSO is a global leader when it comes to the manufacture and distribution of A/C systems and A/C Compressors, preferred by several top vehicle makers including Audi, BMW, Toyota and Volkswagen. DENSO’s aftermarket range features the same manufacturing process and technology to ensure technicians always receive optimal performance with DENSO parts.

With an extensive range of OE-quality aftermarket A/C Compressors available, DENSO helps technicians everywhere keep their cool when it comes to performing compressor maintenance and replacements.

A/C Compressors are also an integral part of hybrid and electric vehicles. For more information on the role of the A/C Compressor as part of the EV powertrain, read this article.

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