car ac maintenance

Figure 1: A man is inspecting the car air conditioning system.

Nowadays, cars have entered into our daily life. And the car is the most used traffic tool. This article will take you to look at the common failures in cars as well as how to solve them. Besides, we give you two methods to detect the leaks in the car ac system.


A condenser is a heat dissipation component in the auto air conditioning system. It is located in the front of the car, which makes it easy to adhere to all kinds of dust and debris leaking into the clearance of the engine cover. For example, catkins in spring, attached to the condenser will lead to bad heat dissipation performance of the air conditioner condenser, which directly leads to the air conditioner not cooling.

the condenser is inside the car head.

Figure 2: The car’s condenser.

How to Clean the Condenser

You need to adjust the pressure of the water gun within a proper range. You should clean the condenser from top to bottom, and not clean the condenser horizontally, so as to avoid damaging the condenser radiator.

When you clean the surface of the condenser, a lot of dirty water will flow out from the bottom of the car. At this time, it is necessary to continue cleaning it until the water becomes transparent, which means that the condenser and the tank have been cleaned thoroughly.

Air Filter

As the use time of the air filter increases, the dust and impurities adsorbed on the filter will be more and more. When the dirt accumulates to a certain extent, the surface of the air filter is easily blocked, which leads to the insufficient air volume of the air conditioner, affecting the refrigeration effect of the air conditioner.

In addition, if there is an abnormal smell after opening the air conditioner, it can also be judged that the air filter is too dirty.

someone is holding the air filter

Figure 3: Air filters.

Clean or Replace the Air Filter

In general, when the vehicle travels 5000 kilometers, it is recommended that the air filter be cleaned or replaced, depending on local pollution conditions. The air filter of the car is made of paper. Due to its fragile feature, you should gently pat it with your hand or knock it on the ground several times to make the dust attached to the filter paper fall off. If you can use the air gun to blow it, you should be careful not to let it get wet.

Air Recirculation Mode

The air conditioner in the car is generally in the outside air mode by default. If your air conditioner is not cooling, you can see whether it has been in the long-term outside air mode. Because the external recirculation will let the external high-temperature air enter, the cooling effect is naturally not as good as that of the inside air mode. When you are driving the car, the effect will be reduced.

Use of Inside & Outside Air Mode

When driving on city roads, you can use the inside air mode. It’s because, in congested sections, the surrounding exhaust pollutant content is larger. After being in the inside air mode for a long time or in a place with clean air, you can open the outside air mode or open the windows for a while to avoid hypoxia or air turbidity in the car.

Aging Belt

This fault is not common, because the replacement cycle of the belt in many cars is very long. But if there is a failure with the belt earlier than the replacement cycle, it may cause a skid in driving, resulting in the air conditioner compressor working abnormally and not cooling.

car air conditioner belt

Figure 4: The car ac belt.

Belt Replacement Cycle

The change period of varied brands of cars may be different, and you should check the user manual (or maintain manual) that describes the specific regulation. In general, it is 60,000-70,000 kilometers or about 5 years to replace, and you’re supposed to replace it in advance close to the specified replacement time.


Confirm that the refrigerant (including fluorine, freon, R3134a) dose is normal.

Lacking the refrigerant, or excessive refrigerant will lead to the air conditioner not cooling.

Under normal circumstances, after a 2-year or 3-year run of the car, you should add the refrigerant.

If there is a need to frequently add it, it may be due to the leakage of the air conditioner pipeline. You then need to go to a professional auto repair shop to check and repair the car.

adding the refrigerant

Figure 5: Adding the refrigerant to the car.

How to Determine to Add the Refrigerant

You should go to the 4S shop to deal with it. Adding and discharging the refrigerant involves strict technical parameters and operation sequence. The illegal operation may lead to accidents. Therefore, You should ask a 4S shop for professional maintenance after judging that the refrigerant is leaking.

Other Faults

If the above conditions are eliminated, it is possible that the failure of a very few components causes the air conditioner to lack the refrigeration effect, such as the air conditioner compressor, and the temperature sensor. In this case, it is also necessary to go to the 4S shop to ask professional maintenance workers for help.

Methods of Car AC Leak Detection

Using Soapy Water

Refrigerant leakage will include lubricating oil, so if you find there is oil somewhere, you should use your hand to touch and inspect the leakage or wipe it with a clean cotton cloth. If there is still oil dripping from the leakage, you can determine the leakage of the automobile air conditioning system. But if there is no oil leakage after that, you should check for leakage using the soapy water. Evenly and completely brushing the possible leakage parts with the soapy water, and then carefully observing it. If there occurs a bubble, it verifies the leakage.


This inspection method cannot check the leakage of the compressor, condenser, evaporator, and other parts that are not suitable for water and are difficult to observe. Using soapy water can detect leaks of the pipeline. Leakage of high-pressure pipeline can be detected no matter if the air conditioner is in operation, while leakage of low-pressure pipeline can be detected only if the air conditioner stops.

Vacuum Leak Detection

After vacuuming the refrigeration system, you should keep the vacuum of the system for at least 60 minutes, and then observe whether the value of the vacuum pressure gauge changes. If the vacuum indication does not vary, it indicates that the system has no leakage, if the vacuum indication has risen, the system has leakage.


This detection method will only show whether the refrigeration system leaks, but can not determine the specific parts of the leakage)

Related Info

Car AC Compressor Troubleshooting-- Best Suggestions

Everything You Need to Know about Car AC Compressor Magnetic Clutch