How to check for freon in a car air conditioner

The question is how to check the air conditioner in a car often worries future car owners who have decided to purchase a used car, however, those who already drive a car with air conditioning may be wondering if the air in the cabin has suddenly stopped cooling properly.

Ideally, for this, it is advisable to contact a specialized car service center, since they have not only qualified craftsmen, but also the appropriate special equipment. However, you can also check the operation of the air conditioner in your car with your own hands. Thus, the verification process should consist of several stages - checking the immediate serviceability of the air conditioner, the condition of its compressor, compressor clutch, oil and freon levels, as well as tightness in the system.

How to check the performance of the air conditioner

How to check any air conditioner in a minute?
Start the car, turn on the air conditioning. Next, near the compressor or throttle, simply touch the two pipes of the lines: high pressure (thicker) and low pressure (thinner). The high pressure tube should be hot (about 50 degrees), and the low pressure tube should be cold (about zero). If there is not enough gas in the system or it is not sealed, or the compressor is faulty, then the temperature of the tubes will be approximately the same, which means the air conditioner will not work. Old type automobile compressors operate in two positions: on. and off, the new type has smooth adjustment. This helps reduce engine load and save fuel. The load may vary depending on the temperature in the cabin and engine speed: when you press the gas sharply (for example, when overtaking), the compressor may turn off completely, allowing you to transfer all the engine power to the wheels. The pressure in the air conditioning system does not depend on the amount of gas, but on its temperature. This is why freon is charged in kilograms. Even with a minimum amount of gas, the air conditioner will turn on, but will not cool well and the compressor will quickly fail. Excessive amounts of gas are also harmful: freon will not have time to evaporate in the evaporator, and will enter the compressor in a liquid state, which will lead to its fatal failure. For these reasons, it is necessary to refill the air conditioning system in the quantity strictly specified by the manufacturer, and only at specialized service stations and car services, taking into account the amount of gas remaining in the filling tubes (usually about 50 grams).

For preventive purposes, it is necessary to turn on the air conditioner even in winter, preheating the interior, and then turning on the supply of cold air, and to prevent corrosion of tubes and connections, keep the under hood clean, then the air conditioner will last a long time without breakdowns, and the car interior will delight you with coolness even in the most hot day.

Anyone who purchases a car equipped with air conditioning, especially a used one, should understand that its repair and maintenance can cost more than one hundred dollars. Even if at the time of purchase it is technically advanced and serviceable equipment, it can break down and even fail completely. For this reason, you need to know how to check the air conditioner in a car with your own hands.

Everything should start at the stage of purchasing a vehicle in conversation with the previous owner. If it turns out that it hasn’t been refilled for a long time, or the pipe is cracked, or freon is leaking, or something similar, then before purchasing you need to go to specialists to assess the repair. And it can reach hundreds of dollars.

When to diagnose a car air conditioner

The operation of a car air conditioner is not so simple, and without knowledge of the elementary laws of physics it will be difficult to understand. True, in order to adhere to the manufacturers’ recommendations regarding device maintenance, this is not required. But if we talk about preventing breakdowns, then understanding the principles of operation of the climate system will not be superfluous. The main component of the vast majority of modern air conditioners is freon - a substance from the group of complex fluorinated hydrocarbons (ethane, methane, etc.), the distinctive feature of which is a boiling point in the range of minus 30 - 50 degrees. Under normal conditions it is a volatile gas.

In the climate system, freon circulates in a sealed circuit and is constantly under pressure. To force the refrigerant to circulate, a compressor is used, which compresses the gas in a high-pressure chamber, thereby increasing its temperature and creating a high-pressure area. Reaching the condenser, the gas enters the radiator tubes, cooled by the air flow generated by the fan. A physical phenomenon called heat exchange occurs - the tubes heat up and the freon cools, condensing and turning into a liquid.

At the same time, the pressure in this area continues to remain high, pushing the refrigerant further into the receiver-dryer. The purpose of this unit is to clean freon from contaminants and complete the change in the state of aggregation of freon. The further path of liquid freon runs through a thermostatic valve, the purpose of which is to reduce the pressure of the refrigerant and further cool it. Simply put, the expansion valve ensures that freon is only in a gaseous state at the outlet of the evaporator.

Once in the evaporator, which is again a radiator, the highly cooled freon evaporates, lowering the temperature of the warm air flow supplied from the passenger compartment. The cooled air is directed to the baffles, and the heated refrigerant is directed to the compressor. In this area, freon is under low pressure. The cycle closes, providing the interior with air cooled to the required temperature.

When the car air conditioner is turned off, the pressure in the system is equalized because the compressor stops creating excess pressure at the outlet. It is clear that any gas must be in a sealed environment, otherwise leaks are inevitable. In the case of a multi-component automobile air conditioner, such tightness is not easy to ensure. Freon leaks lead to a decrease in pressure in the system, which forces the compressor to work with increasing load, which inevitably leads to malfunctions. And the later they are identified, the more expensive it will cost to restore the operation of the air conditioning system.

https://www.youtube.com/watch?v=dOZcVTnnFOM

The task of ensuring tightness is complicated by the presence of a large number of components of the climate system and, accordingly, the same number of connections. The well-known wisdom that says that quantity always turns into quality is also true here: the more connecting elements, the higher the probability of loss of tightness of at least one of them. The reasons for leaks can be different:

manufacturing defects;
negligence of the technicians who performed maintenance/refilling of the air conditioner;
natural wear and tear;
use of low-quality materials.

One way or another, over time, any climate system becomes less than perfectly sealed, requiring periodic replenishment of refrigerant. If refueling is carried out by unskilled or simply irresponsible workers, the risk of premature breakdowns of the car air conditioner increases, and they do not always have pronounced symptoms. And yet there are a number of signs by which one can judge that the system requires urgent diagnosis.

The main one, of course, is the appearance of noise that was not there before, which manifests itself mainly when the climate system is turned on and operating. Typically this phenomenon is accompanied by a decrease in air conditioning efficiency. The reasons for the appearance of extraneous noise can be different. In some cases, the direct culprit is the condenser, a unit that is most susceptible to contamination due to the ingress of dust, dirt, moisture, salts and other aggressive substances along with the flow of air forced by the fan, leading to depressurization of the system.

No less often, the culprit of increased noise when the air conditioner is turned on is the compressor or its individual components (for example, a worn out belt, a leaking oil seal, a compressor shaft bearing that has begun to deteriorate). But noticing the appearance of noise is one thing, but localizing it is quite another. Even if you know for sure that a suspicious noise, hum or grinding noise is coming from the area where the compressor is located, it can be very difficult to determine the cause of the malfunction.

The second obvious sign indicating that diagnostics of the car air conditioner is required is the appearance of unpleasant odors in the cabin. Most often, this is observed immediately after turning on the air conditioner, which can be explained quite simply: waste products of microbes that actively multiply in some components of the system begin to be removed along with the air flow through the deflectors, entering the cabin. The evaporator can be a breeding ground for microorganisms, but the most favorable conditions for their reproduction are created when the climate system in the evaporator is turned off. So the appearance of an unpleasant odor is a clear signal that the air conditioner components are dirty, which can result in a more serious breakdown.

How to check the oil in a compressor

What is the pressure in a car's air conditioner when refueling
? When the compressor is running, oil circulates through the system; after the air conditioner is turned off, some of the oil remains in it. We check the oil level in the compressor as follows:

let the air conditioner run in cooling mode for about twenty minutes;
we check the oil level in the compressor through the inspection window - it should be at a level above the lowest point, but above 1/8 of the height of the inspection window;
However, the oil should not foam, and if this happens, there is likely a freon leak that should be repaired. If the oil is higher than normal, excess oil must be removed from the system; if the level is low, oil must be added.

Checking the performance of the car compressor

You can check whether the compressor itself is working using a pressure gauge, but the check should be carried out in a specialized car service center using special equipment:

we connect the installation to the car’s air conditioning system, start the engine;
turn on the air conditioner, watch the pressure gauge readings, the pressure on the device with a working compressor should increase;
if the pressure rises, the compressor is in order, and if there are faults in the system, they need to be looked for in other elements of the air conditioner.

Antibacterial cleaning of the evaporator-conditioner

How to check a car's paintwork

If you want the smell in the cabin to be pleasant when the air conditioner is operating, then it is necessary to systematically clean the evaporator. Do-it-yourself repair of the air conditioning compressor in this episode can and should be done. It is recommended to clean the air conditioner once every six months. We will need a spray cleaner for the car. Its contents are sprayed so that it falls on the evaporator.

At the same time, we activate the recirculation mode at maximum speed. This spray also forms a film on the evaporator. The goal is protection from external influences and prevention of the emergence of new microbes and pests. For high-quality operation of the air conditioner, it is recommended to turn it off a few minutes before arriving at your destination to dry the evaporator. This simple advice will help you operate your air conditioning compressor for a long time.

Service Issues

Maintenance of your car refrigerator should not be neglected either. At the same time, some owners noticed an unpleasant odor in the cabin, while others observed obvious overheating. There is nothing to be surprised about, because this is clear evidence that the inspection has not been carried out for a long time.

What exactly is the service? First of all, you need to regularly clean the condenser located in front of a traditional radiator. As a rule, after each summer season, poplar fluff, adhered insects and other contaminants are discovered. This causes the honeycomb to become clogged and the air conditioner will no longer work properly.

You can clean it with water pressure, but you should act carefully so as not to bend the honeycomb, otherwise you will have to buy a new condenser. It is also acceptable to use special radiator detergents. Then rinse everything well with water and blow with a fan.

Another unpleasant moment is the presence of fungus or dirt on the evaporator, which leads to the appearance of an unpleasant odor. There are several ways out here:

Try to get to the evaporator and rinse it thoroughly. Unscrewing its element is strictly contraindicated!
Use special detergents for the internal parts of the car air conditioner. It is not necessary to disassemble the front panel; it is enough to use an extension cord that is used to apply them to the evaporator. After some time, the product is washed off when the air conditioner starts working. This simplifies the cleaning process.

There are situations when at first glance it is clear that the entire system is working properly, but nevertheless it does not work correctly. And if the problem is the lack of refrigerant, then the problem can only be solved by contacting a specialized car service center. It is impossible to charge the device with freon without the necessary equipment.

Only specialists will be able to diagnose at a high level and, if necessary, carry out all the necessary operations.

How to check the air conditioning compressor clutch

Car air conditioner malfunctions. 7 main car air conditioning problems

The most reliable way to check the air conditioning system is diagnostics at a specialized car service center, but the buyer does not always have the opportunity to check the serviceability of the car at a service station. Often the seller, when asked if the air conditioner works, begins to answer evasively:

the system works, but freon is not charged;
one of the pipes has burst, it needs to be replaced, but the air conditioner is fine;
We took off the belt for the winter because it was torn.

All answers of this kind should be alarming, since the main reason for the malfunction of the air conditioning system is the failure of the compressor; it is this part that is the most expensive in the air conditioning system. In a compressor, the clutch is the first to fail, so its functionality should be checked.

How to check the air conditioning compressor clutch? We do the following:

turn on the air conditioner operation button, the power indicator should light up;
When turned on, a click should be heard in the engine compartment, so the clutch connects to the compressor itself.

It is advisable to carry out the check together - one of the participants presses the button, the second person looks under the hood to see how the coupling is connected to the air conditioner. When the compressor is turned off, only the pulley rotates on it, and the pressure plate remains in place. When the air conditioner is turned on, the plate is magnetized to the pulley - the drive hub begins to rotate along with it, which is why a distinct click is heard.

It should be noted that this check is not valid for all cars; on some modern models, the plate rotates with the pulley, and the connection to the hub occurs internally. There are cars of complex design with many additional units, and it is difficult to examine the compressor clutch in the engine compartment. But in any case, you should focus on the click; it should be audible when the coupling is magnetized. If you do not hear a click, most likely the clutch is not engaging, and this indicates a compressor malfunction.

There is another way to check the functionality of the clutch; for this you do not need to start the engine. We check as follows:

turn off the engine, disconnect the power from the compressor by disconnecting the plug;
We connect the positive terminal of the battery with a wire to the connector on the compressor; when the wire is connected, the clutch should work - you can notice how it moves, and at this moment a click is heard;

In this way, you can check the clutch even without freon in the system; the working clutch should still move with a characteristic sound.

What should you pay attention to?

Diagnostics of a car air conditioner is the process of assessing its operation. As stated above, identifying the causes of a malfunction in your car first of all comes down to checking the freon level. You can check the level in the area of the dryer, but you need to keep in mind that not all installations are equipped with it. Looking into a special hole, you can see freon. If it has bubbles and the color of the liquid is white, then you need to refill the device. Only if the freon is transparent and there are no bubbles in it, its condition can be considered normal.

When diagnosing a car air conditioner, you should first pay attention to the following breakdowns:

various cracks and mechanical damage;
When checking the air conditioner in a car, you should pay attention to contamination of the unit, which may be due to wear and tear of various components;
servicing and technical restoration of operability must be carried out in the event of a malfunction of the system’s electrical circuits;
if the device is used incorrectly, traces of rust may appear on its parts and elements - corrosion in general has a detrimental effect on the operation of the air conditioning system;
non-compliance with the rules when adjusting;
wear of system parts, in particular bearing devices, relays, unit brushes or contacts.

Flushing the evaporator device

In practice, diagnostics and repair of car air conditioners are carried out in the event of a breakdown:

The compressor, its failure will be indicated by noise during operation of the air conditioner, as well as oil on its housing. Typically this problem is caused by depressurization and fluid leakage.
The failure of the evaporator is due to the impact of corrosion on this unit as a result of contamination of the condensate drain line.
Breakdown of the receiver, which is used to remove condensate from the unit and clean freon from dirt and wear products. With such a malfunction, the lines freeze, and the condenser itself can randomly turn off.
Failure of the thermostatic valve. In this case, the air will not be cooled constantly, but periodically, the evaporator pipes will freeze, and the air conditioner can automatically turn off and on. The main reasons in this case are damage to the expansion valve, incorrect adjustment, or the presence of condensate or air in the system.
Damage to the ventilation device, which is necessary for additional cooling of freon. Not all air conditioning systems in modern cars are equipped with a fan. Typically, fan failure is caused by wear of the bearing device or malfunction of the electrical circuit.
Failure of the pressure controller. The purpose of this element is to turn off the condenser if the freon pressure parameters are critical.

In order for the car air conditioner to work properly and to avoid problems in its operation in the future, the system must always be kept clean. From time to time, the driver must clean the components of the device, while following the rules for setting up and using the air conditioner. For example, a compressor breakdown may be caused precisely by improper operation, in particular, turning on the air conditioner at full power when starting the engine. Under no circumstances should this be done, since the system must be cooled gradually.

As a preventative measure, the device should be turned on from time to time, even in winter (video author - Tim Service).

How to check the air conditioner in a car in winter

It is more difficult to check the air conditioner for leaks in the winter, especially when the temperature drops below - 10°C, since there is a strong drop in the pressure of the refrigerant. Before turning on the air conditioner, you need to warm up the air in the cabin until the entire dashboard is warmed up. In such cases, it is possible to fool the evaporator sensor. The same sensors that are located under the hood will also allow the system to start due to the freon warming up and the pressure level rising.

Now press the air recirculation button. Some modern cars are equipped with climate control systems

They stop paying attention to temperature indicators and forcefully start the compressor in such cases. Now you can probe the main lines of the system with your hands, as already described above

Of course, such a diagnosis cannot be called 100% correct - for a more accurate determination of performance, special equipment and qualified personnel are needed.

Algorithm for refilling a car air conditioner with freon

To perform this operation, it is necessary to prepare the following tools, devices and consumables:

hoses;
pressure gauge;
a cylinder filled with freon;
adapter.

The first thing to do is to find the line in the engine compartment through which the refrigerant circulates. Then you need to find the hole for refilling freon and clean it using a special cap. The area around the hole should also be thoroughly cleaned and after removing the cap, try to put on the filling hose as quickly as possible.

You won’t be able to refuel yourself, so invite an assistant to start the power unit and keep it running at idle with the tachometer reading around 1500 rpm. After this, he needs to turn on the air conditioner, setting the regulator to the maximum cooling level. At this time, you need to prepare the freon cylinder for refilling: turn it over, open the tap, open the low pressure valve on the hose and connect the container with the refrigerant to the line. All these operations should be carried out with the air conditioning system already turned on as quickly as possible.

While freon is being poured into the main line, you will need to control this process by monitoring the pressure gauge scale. For different models of car air conditioners, the level of the nominal pressure value is different, study this point before starting refueling. If you do not find the required figure, focus on the indicator 285 kPa. In this case, you need to make sure that no air gets into the refrigerant - in this case, bubbles will be visible in the window on the receiver. All this time the engine should be running at idle speed. Refueling should be completed when the temperature of the air entering the cabin from the air conditioner drops to 6 - 8 degrees. To do this, you need to close the valve and remove the cylinder from the filling hole.

The whole process can and should be learned by watching several different videos that homegrown experts post on YouTube.

How to check the operation of the Renault Logan air conditioner

If the air conditioner does not turn on or does not cool enough, you need to diagnose the air conditioning system. First you should check the gas pressure (freon), the check is carried out using a special pressure gauge. There are fittings for installing a pressure gauge; they are located almost on the bends of the tubes in the area of the right side member.

You can also check the presence of refrigerant by pressing the valve in the fitting, which is located under the cap. If the air conditioner is charged normally, when you press the valve, gas under pressure will exit the system and it will hiss.

If gas does not come out, there is a leak in the system - it must be found and the malfunction repaired. After eliminating the freon leak, the system should be refilled with gas. There are ways to independently refuel an air conditioner with freon, but it is still recommended to refuel at special stations in a specialized car service center.

In some cases, the car is fully charged with freon, but the air conditioner does not turn on. It should be noted that the clutch may not engage for several reasons, and the defect is not necessarily hidden in it. Reasons for clutch failure:

there is a break in the wires, power is not supplied to the compressor;
The power relay does not work; on Renault Logan it is located in the mounting block, in the engine compartment on the left side (near the battery).

Checking the relay is quite simple - you need to dismantle it, connect the contacts under it with a piece of wire, and press the button to turn on the air conditioner. If a loud click is heard when the connection is made, this indicates that the A/C clutch is working properly and the relay needs to be replaced.

If there is insufficient cooling of the air inside the car, you should diagnose the equipment at a car service center on a stand and check what pressure is in the system. The pressure must be certain, not lower or higher than the prescribed norm.

The air conditioner may not cool the air enough if the condenser (radiator) is clogged with dirt. When air is not supplied to the radiator cells, the system is not cooled sufficiently and it does not work efficiently. On Renault Logan, the condenser is located at the front of the car, and to clean the radiator from the outside, you need to remove:

radiator grille;
front bumper;
electric cooling fan.

It is not advisable to disconnect the condenser from the tubes, since in this case the car will have to be refilled with freon. The following elements may also be faulty in the air conditioning system:

receiver-dryer, signs of its malfunction - spontaneous shutdown of the air conditioner, freezing of hoses in the system;
thermostatic valve - if it is defective, cold air enters the cabin intermittently;
pressure sensor - if it is faulty, the air conditioner is unstable;
evaporator - when clogged, an unpleasant odor appears in the cabin.

When buying a used Renault Logan, it is recommended to go for diagnostics to a car service center and check the operation of the air conditioner using special equipment.

Checking the car air conditioner for leaks

You can check the car air conditioner yourself for leaks not only when purchasing a car, but also if signs indicating this malfunction occur. A leak can be judged by the following signs:

decreased air conditioning performance (the unit does not cool the air in the cabin enough);
freezing of the external walls of the air conditioning system lines;
the appearance of oil stains on the pipes of the air conditioning system.

If the level of freon in the system is critically low, it will be impossible to turn on the air conditioner, since the system will automatically turn it off based on data from the corresponding sensor.

How to check freon in a car air conditioner

The first step is to check the presence of refrigerant in the car air conditioner visually. The easiest method for monitoring the freon level in your air conditioner is to simply use the sight glass on the top of the receiver-dryer. It is specifically designed for visual monitoring of the presence and level of refrigerant.

In some cases, this peephole is simply covered with dirt and/or dust. Accordingly, it needs to be wiped with a rag.

To check freon, you need to start the engine and turn on the air conditioning at full power. After this, through the peephole mentioned above, you need to look at the condition of the freon. One of the situations described below is possible.

Bubbles appear in the liquid , which disappear after a short time. Conclusion - the amount of freon is sufficient for normal operation of the air conditioner.
Bubbles in the liquid initially appear in large quantities, but then they become smaller, but they DO NOT disappear completely. This means that freon is at a critically low level . Refueling required.
Liquid freon has a milky white color, and there are always bubbles on its surface. Freon level is below the permissible norm . The air conditioner cannot be used until the system is charged with freon.

Along with refilling with freon, it is also advisable to check the system for leaks in order to prevent refrigerant leakage in the future.

Checking the car air conditioner with nitrogen

Visual monitoring of the freon level is a very conditional method. This is due to the fact that modern R134A freon, when mixed with synthetic compressor oil, does not leave any oil traces. Therefore, for diagnostics it is better to use special equipment and measure the gas pressure in the air conditioning system.

Leak points are usually the junctions of various elements of the air conditioning system. However, leaks are also possible through the walls of rubber hoses or the compressor seal (if they are mechanically damaged or simply due to old age, when the rubber loses its elasticity).

The test is carried out in a system under pressure, the value of which must be at least 3.5 atmospheres. If there is little freon in the system, then it must be completely removed, and the test must be carried out with nitrogen (the full name of the gas is OFN, oxygen freenitrogen - nitrogen without oxygen). This nitrogen leak test is carried out only at service stations. Using this method, you need to check the following places in the air conditioning system:

all tubes and connections;
compressor shaft;
compressor service valves and gaskets;
condenser and evaporator tubes;
receiver/dryer connections;
Pressure Sensors;
paired spring lock connections;
hoses.

Before checking, you must prepare a soap solution. To do this, it is better to use bar soap and “soft” water (without significant impurities of metal salts). The solution should have such a consistency that soap bubbles easily form on the surface of the water. The test algorithm using nitrogen is as follows:

If there is freon in the system, it must be removed.
The OFN cylinder must be connected to a special service connector for the air conditioning system in the car.
Open the valve on the cylinder and set the pressure in the system in the range of 10...15 atmospheres, then close the valve.
Using a brush or rag, apply the soap solution to the suspected leaks listed above. If nitrogen comes out of the system under pressure, this will be clearly visible from soap bubbles forming on the surface of the part. Accordingly, the larger and more intense the bubbles form, the more significant the leak in this area.
After testing is completed, all nitrogen from the system must be removed.

During operation, the maximum permissible pressure must not be exceeded (be sure to use a pressure gauge and pressure regulator). In addition, you should not turn on the air conditioner while there is nitrogen in the system.

Self-testing with nitrogen in a garage hardly makes sense, since additional equipment is quite expensive. Accordingly, it is better to contact a specialized car service center for such testing. As of the summer of 2022, the price of such a procedure is in the region of 800...1200 rubles, depending on the service itself, the equipment used, as well as the type of air conditioner (volume of nitrogen used).

Checking for leaks using an electronic leak detector

Leak detector - designed to find even the smallest leaks. The device is quite specific and expensive, therefore, they are used mainly by professional technicians in car repair shops. The algorithm for using a leak detector is as follows:

The test must be carried out in a closed room, without drafts, and it is advisable to ventilate this room first.
The air conditioning system must be charged with freon, even partially.
The leak detector has a special test sensor, which must be brought to the sites of suspected refrigerant leaks.
The check must be performed from the top to the bottom, since freon is heavier than air, and accordingly, its bulk is located at the bottom.
When a significant concentration of freon is detected in the air, the test device emits a sound signal. Depending on the model and settings, the audible and/or light alarm will vary depending on the concentration of gas detected.
If a freon leak cannot be detected with the air conditioner turned off (especially when the system is partially charged with refrigerant), then you can turn on the unit in order to increase the pressure in the system. After this, repeat testing using a leak detector.

Leak test with ultraviolet lamp

To use an ultraviolet lamp to check the air conditioning system for leaks, you must first add a special dye with fluorescent properties to the newly refilled freon. It is sold separately in auto stores. It must be added to the low pressure line in accordance with the instructions included with the packaging.

Accordingly, when freon tinted in this way leaks, it is clearly visible under the influence of an ultraviolet lamp (usually it has a purple, red or green tint). This test method is simple and inexpensive, so all car owners can be advised to add the appropriate dye to it when refilling new freon. And then, by literally illuminating the joints of the tubes with an ultraviolet flashlight, you can see where the leak is.

Why is it important to monitor the condition of your air conditioner?

The main reason is the expensive repair of the cooling system. The cost of refilling with freon starts from 1000 rubles, and replacing a broken compressor can cost 1000 rubles. e. Inexperienced drivers often “get money” in the following situations:

continue to operate a malfunctioning air conditioner, causing the compressor or expansion valve to fail;
buy a used car with a faulty air conditioning system, not knowing what it will cost.

Cunning car sellers on the secondary market often turn off a faulty cooler in order to deceive the buyer - they remove the drive belt, release freon from the circuit, and so on. To avoid unnecessary costs after purchase, you need to know how to check the operation of the air conditioner in a car. If you suspect a malfunction, you will be able to demand a price reduction by the amount of repair.

Repair

Specific measures to eliminate faults are taken based on their nature, location and suitability for repair.

They can be radical (with complete or partial replacement of damaged nodes) and palliative:

with soldering of perforated parts of connecting tubes;
with washing of areas clogged with clots of debris.

At the end of the repair, it is necessary to carry out a control pressure test of the system with compressed air. If the tightness is not broken anywhere, refrigerant is pumped into the air conditioner lines.

Let's move on to diagnostics

So, we have identified the most important components of the system and are now starting independent diagnostics. Even if you have no previous experience of such work, it can be quite effective. We turn on the air conditioner and wait for the noise of the compressor. We touch the metal part of the return line with our hand. In 10-15 seconds you will feel your hand starting to freeze in the literal sense of the word.

Carefully touch the metal tube connecting the compressor to the radiator. As a rule, it is either warm or quite hot if the temperature outside exceeds at least 20°C

We check the condition of the thinnest line that leads to the radiator from the compressor. It is bad if it is very hot, because this is a sign of contamination of the system, either oversaturation with freon, or a broken fan.

If such actions do not lead to one of the described effects, you need to contact experienced car air conditioning technicians. In this case, you will have to measure the pressure in the system - it is possible that we are talking about a refrigerant leak or other, much more serious malfunctions.

In such cases, a careful inspection of the pipes with their attachment points, the receiver-dryer, the compressor, and the air conditioner radiator will help. If there are traces of fogging, oil drips, or traces of dirt, then you should be wary of freon leaking from the system.

Checking pressure and sensor

The pressure sensor is responsible for monitoring the pressure in the system within normal limits.

If the pressure rises excessively, the sensor is triggered and signals the need for an emergency shutdown of the air conditioner, which the control body immediately does by turning off the compressor.

Checking the car air conditioner sensor.

First of all, when checking, you need to carefully inspect the sensor body to see if there is any damage on it.

The electrical circuit of the part is made fail-safe; if it opens, the fan is turned on forcibly, which helps reduce pressure by cooling the freon. But this is not a standard mode, so the faulty sensor needs to be replaced.

In different models of car air conditioners, the location of the sensor may be in different places. Therefore, you must first find where it is. Then you will need to check the resistance level.

For this:

remove the electrical connectors from the terminals of the unit.
the tester is set to the position for measuring resistance in the range of 100 kOhm or more.
We touch the probes of the device to the terminals in pairs.
when the air conditioner is turned on and the pressure in the system is high, the resistance indicator should be at least 100 kOhm, which indicates an open circuit.
if the tester screen shows a value less than 100 kOhm or close to 0, this means that the circuit is closed, such a sensor must be replaced if it is faulty.
at low pressure in the system, the tester should show a resistance value of no more than 10 ohms when checking, which indicates that the device circuit is in a closed state.
accordingly, if the indicator is higher, then the sensor needs to be replaced because it is faulty.

If the sensor, according to the measurements, does not work correctly, it is worth testing it for a short circuit.

The check is carried out as follows:

when there is low pressure in the system, one probe of the tester is set to ground (touches the body), the second is touched in turn to the terminals of the device.
if the device is in good condition, then values of 100 kOhm or more will appear on the device display, which indicates an open circuit and the absence of a short circuit.
for values less than 100 kOhm, the sensor requires replacement.

The unit is disposable and cannot be repaired. Repair is carried out only by replacing it with a new, working sensor.

How to deal with glass fogging in winter Topic author Tirza

Good people, please help me with advice. In winter, what is the best way to combat fogging? I tried different things: only the stove; stove - recirculation - air conditioning; The windshield fogs up, but the sides and rear do not. And does the air conditioner work in winter, or does the electronics turn it off?

Checking the car air conditioner.

Diagnostics and selection of cars. Dnepropetrovsk VK group: rel=0;controls=0;showinfo=0;iv_load_policy=3;" frameborder=”0″ allowfullscreen>

Dmitry (Mahdi) the air conditioner seems to be working))

Roman (Rosanne) The air conditioner is working, it dries the air. You just have a stove. Or the climate?

Roman (Rosanne) What is the mileage?

Mikhail (Quinlan) Turn on airflow to three or four. And there’s no way to combat fogging of the rear windows(

Igor (Udwamsa) I visited the dealer, and in response to my question about fogging, he answered that the air conditioner does not turn on in winter, and the airflow needs to be set to maximum) But no matter how you look at it, the problem is not solved(

Vladimir (Demonte) What is the temperature outside?

I turn off the air conditioner. I turn off the recirculation (turn on the air intake from the street), the air flows through the windshield to the feet, when driving around the city it does not fog up and does not freeze.

Igor (Udwamsa) Yesterday it was -1 degrees outside. The mode is the same: windshield - legs, heater and fan at maximum. Only the windshield and half the front side windows were clean. And the rear ones - there was not even a hint of sweating.

Svetlana (Debbie) I put my frontal feet on and nothing fogs up on me, then I switch and that’s it. you need to have some air blowing into the cabin, then it won’t fog up, it’s a little hot, but then switch

Vladimir (Demonte) Igor, the main thing is that fresh air comes in from the street.

Irina (Joli) Igor, have you tried turning on the heated rear window? It sweats immediately. Yesterday after washing, my front side panels began to fog up and freeze in the near corners. but I think this is due to washing the car and remaining moisture, plus the frosts have gotten worse again.

Andrey (Vrajesa) I have a spray. You wipe the glass from the inside with it and don’t fog up) it’s enough for about a week! so if it’s not cold, I don’t even turn on the heater/air conditioner

Irina (Joli) Andrey, oh, I have it in my trunk too. Thanks for reminding me)))

Igor (Udwamsa) Irina, the problem is mainly with the rear side, and partly with the front side. And mostly in wet weather. The day before yesterday there was porridge on the roads, puddles, and snowfall)) So visibility is bad, and everything is foggy. And today the frost in the morning is 20, I turned the stove on to maximum, and there are no problems at all).

Alexander (Cadwgawn) it’s strange why the air conditioner doesn’t work in cold weather, when I’m sweating outside, at least 30 degrees below zero, I turn it on and everything dries as it should.

Irina (Joli) Sergey, I think that the operation of the air conditioner is designed to reduce high air temperatures, and in winter they are low. But it works for drainage.

Alexey (Skjolddis) I put it on speed 3 and turn it on to “frontal feet and interior”, close the middle air ducts and set the temperature one click above the middle (that is, to heat) and everything doesn’t drag on me and the car is warm.

Alexey (Skjolddis) In severe frosts, do not set the heat to maximum! Since large differences cause the glass to simply crack when the car is skewed, this was tested from personal experience (on a work car)

Irina (Joli) Sergey, I don’t understand why you got the idea that the air conditioner doesn’t work in cold weather. I was about to believe it, although I doubted it, because... on the previous car the air conditioner worked at any time of the year. So I decided today, standing in a traffic jam, to check it out of nothing to do. Yes, the air conditioner works great, you just need to move the needle to the blue zone all the way, start the air conditioner and wait a little until the warm air passes, then such a beating starts. ))))

Alexander (Cadwgawn) Irina, I have something to do with it, people wrote above that it does not work in cold weather and some dealers said (everything is written above). I didn’t ask, there is no question in my proposal, on the contrary, I refuted it and wrote that it really WORKS.

How to check the pressure yourself

To do this, you need to purchase a special device called a pressure gauge station. Make sure that it comes with hoses and a tube adapter. Now we look under the hood for a line with a low pressure reading. They are usually thicker than high pressure lines.

We remove the plugs, attach the adapter, and wipe the connection points with a rag. We unscrew the tap at the station and leave the other one closed to prevent refrigerant leakage. Turn on the engine and measure the pressure with a pressure gauge. The normal value would be 250-270 kPa.

Air conditioning system design

To carry out independent diagnostics, the car owner must understand the general principle of operation of the air conditioner, what parts it consists of and where they are located. The system includes the following elements:

An external heat exchanger (technical name is a condenser) installed in front of or next to the engine cooling radiator. Internal heat exchanger (evaporator). Hidden under the front panel of the car. A compressor with an electromagnetic clutch stands near the engine and is connected to it by a belt drive. Tube-shaped lines connecting both heat exchangers. A special substance moves through them - refrigerant (freon). Thermostatic valve (TRV). Most often it is located under the dashboard. The receiver is a dehumidifier in the form of a vertical tank. Installed in the engine compartment near the condenser.

The operation of any air conditioner, including automobile ones, is based on the property of freon to boil and evaporate at a low temperature. At the moment of evaporation occurring in the internal heat exchanger, this substance takes a lot of heat from the cabin air and thus cools it. The gas then moves to a compressor, which raises its pressure and temperature. The further process goes like this:

Hot gaseous refrigerant is pumped into an external heat exchanger, blown by an air flow, and condenses there, releasing the heat taken from the cabin. Having turned into liquid, the refrigerant passes through a receiver that separates moisture and enters the expansion valve. After the valve, the pressure of liquid freon decreases and it is again directed to the internal radiator to evaporate.

The operation of the air conditioning system is controlled electronically, turning it off if the maximum freon pressure is exceeded or at low ambient temperatures (-5 ° C or less).

When should you check?

Operating principle of the air conditioning system

As you know, the air conditioning system is a device designed to cool the air flow in the cabin. When the condenser is turned on, freon begins to compress the consumable material - freon gas, which subsequently circulates through the system. The freon is then heated and enters the evaporator, where it is cooled and converted into liquid. As practice shows, it is often necessary to check the car air conditioner in case of improper maintenance. Often, the main reason that makes it difficult for an air conditioner to operate is poor tightness of the system, resulting in rapid gas leakage.

In any modern air conditioning system, the evaporator is considered the weak point, since it is most susceptible to dust and dirt. With prolonged exposure to external factors on the system, microcracks and other damage may appear on the device, which in any case leads to poor operation of the system. If the compressor is not working correctly, this will lead to the fact that the cooling efficiency of the cabin as a whole will be minimal, while the air conditioner itself will operate noisier. Traces of oil may be visible on the element itself.

Another reason why a car air conditioner needs to be diagnosed is an unpleasant odor. Diagnosing this problem comes down to checking the level of consumables in the system; usually an unpleasant odor indicates the need to clean the system.

Air conditioning compressor

Should I turn on the air conditioner in winter?

Economical buyers, when choosing the configuration of their own future “cab,” reason something like this: “Well, great, it’s more pleasant in the summer, in the heat. But in spring-autumn-winter it’s wasted money”... What a misconception!

In fact, cooling the air is not the only function of the air conditioner. The air passing through the cool evaporator leaves almost all the water on it. It is this that later flows down the tube under the car.

The resulting dehydrated air sparingly absorbs water and, if you direct the flow onto foggy windows, it will quickly make them transparent. Down with rags and napkins!

In the off-season and in winter, it is not hot in the cabin even without air conditioning. Won't you have to wear a warm fur coat for the sake of unstained glass? For this you have a temperature regulator, indicated by blue and reddish sectors. It is connected to the damper. which directs cool and dry air either directly into the cabin (in summer) or through the heater radiator (during the rest of the year). The thermal power of the heater significantly exceeds the cooling capabilities of the air conditioner, so naturally you will not freeze.

Turning on the air conditioner in winter is also good for the air conditioner. Due to long periods of inactivity, the compressor seals dry out and refrigerant may leak. Filling any 80 g costs a pretty penny (usually 50–60 bucks). By starting the unit, you will automatically lubricate the cuffs and significantly increase the service interval. There is no need to be afraid of damaging your precious device - at low temperatures that are unsafe for it, the protection will work and the air conditioner simply will not turn on.

On cars developed 5 years ago or more, to clean the windows from water, turn on the air conditioner by pressing the A/C (Air Condition) button and direct the air flow to the windows or to the windows and feet. (By the way, don’t forget to turn on the heater fan!) Adjust the air temperature using the appropriate knob or slider.

the air conditioner for 20 minutes at least once every two weeks.

to allow the system to be lubricated.

Is it possible to turn on the air conditioner in a car in winter?

As it turns out, using an air freshener in cold seasons is very useful and practical. But when you purchase a car with a very good microclimate system, which costs much more than $2,000, in late autumn or winter, you can easily get a reputation for being a wasteful person, because you may simply not be understood. It’s another matter to buy a car with air conditioning on a hot July day, when the heat outside reaches above forty degrees. Then no one will tell you anything for sure. This article will tell you whether it is possible to turn on the air conditioner in a car in winter, and give practical recommendations on its use and maintenance.

But in fact, a car needs fresh cool air, both in summer and winter. The only problem with car air conditioners is that they are very capricious and in order to be able to use them at the right time for us, we need to constantly monitor them.

It should be refilled at specialized services. If you want to refuel by eye in garages, then 100% soon such refueling will turn out to be much more expensive. If you fill less than normal, then the pressure in the air conditioning system will be insufficient, which means that the compressor will work harder, which will subsequently greatly affect its service life. If you fill in more than necessary, the system tubes will burst from the pressure. So don't take risks and look for a good service with qualified mechanics.

But how to check the health of the air conditioner?

In winter you can check in two ways.

So, the first way to check. It is necessary to heat the car interior to the maximum permissible temperature, then you need to move the temperature regulator to the blue zone and turn on the air conditioning. If this is a car with climate control, you need to set the lowest temperature (Low). Cold air should blow from the heater deflectors. You must remember - it is necessary to heat the interior, because... If the temperature of the air conditioner evaporator is near zero, the air conditioner will not work.

Second way. With the engine running, press the AC button, after a few seconds a click should occur in the engine compartment and the engine speed should increase. This turned on the electromagnetic clutch of the air conditioning compressor drive. If the electromagnetic clutch turns on and turns off after a while, and this cycle is constantly repeated, it means that there is not enough refrigerant gas in the system. Don't be afraid to turn on the air conditioner and heater at the same time. This will not harm the car, but it will benefit you, because... A car air conditioner dries the air very quickly, and moisture causes fogging, and subsequently, freezing of the windows.

Many people try to protect air conditioner pipes. But there is no point in attempting to independently protect air conditioner tubes from corrosion by covering them with protective compounds. Most of the tubes at manufacturing plants are coated with special materials that protect the products from corrosion. Additional protective coatings in this case will only cause harm.

The air conditioner must be used at least once a month, even in winter. As mentioned above, a special oil enters the refrigerant, which, if you use an air conditioner, lubricates the rubbing parts of the compressor. But if this is not done, all the lubricant settles, and during the first spring start, the compressor may simply fail.

Checking the expansion valve

The task of a thermostatic valve (abbreviated as TEV) is to maintain optimal operating conditions for the system of air conditioning units and the coherence of their interaction.

The expansion valve ensures synchronization of the operation of the compressor, evaporator, condenser-radiator, expander, and connecting pipelines.

The thermostatic valve narrows the cross-section of the pipeline, resulting in a decrease in the temperature of the gaseous refrigerant passing through the assembly.

The part regulates the intensity of freon flow, thereby maintaining the optimal gas temperature.

Operating principle of a thermostatic valve.

Despite its importance, the valve is very simple in its design. Its breakdown is quite rare.

Almost the only malfunction (others are extremely rare) is a jammed needle.

The consequence of the needle losing its mobility is an imbalance in the pressure in the low and high pressure circuits of the climate control system.

To check whether the expansion valve is working properly, you need to check the pressure readings in both circuits of the system.

Failure usually occurs in three cases:

in case of mechanical breakdown of the needle.
jamming due to exhaustion in a node that has expired.
installation of an inappropriate part.

There is no point in repairing the valve; it is not intended for that. The only repair option is to completely replace the thermostatic valve with a working part.

Conclusion

The air conditioning system definitely needs regular testing at least once every 2 years for a new car and once a year for a car with six years of mileage.

It is also necessary to carefully inspect and check for operability all components, connecting tubes, and hoses of the climate control system when purchasing a car second-hand.

It is useful to find the problem unit yourself in order to be sure that the technical center will correctly point out the fault to you, and will not try to inflate the cost of repairs by replacing serviceable parts.

Repairing an air conditioner is not cheap, so independently detecting, for example, a freon leak, can save a significant amount.

In some cases, it is simply not necessary to go to a service station. It is quite easy to determine the freon or oil level yourself.

Check the air conditioner from time to time to ensure it is working properly. This will protect you from sudden breakdown, and a small malfunction, which, if noticed in time, can be fixed quickly and cheaply, will not turn into a major problem, which can only be solved at a great expense.

Why is it important to monitor the condition of your air conditioner?

The main reason is the expensive repair of the cooling system. The price of refilling with freon starts from 1000 rubles, and replacing a broken compressor can cost 1000 rubles. e. Inexperienced drivers often “get money” in the following situations:

continue to operate a malfunctioning air conditioner, causing the compressor or expansion valve to fail;
buy a used car with a faulty air conditioning system, not knowing what it will cost.

air conditioner check compressor

Diagnostics of the interior cooling system

The best way to thoroughly understand the air conditioner is to contact a specialized workshop, where the tightness of the system will be tested with a vacuum stand and the operation of the supercharger, expansion valve and receiver will be checked. If this is not possible, you will have to act on your own. Below is an algorithm for checking the air conditioning compressor and other elements of the air conditioning system:

Start the engine and press the “A/C” button to turn on the cooler. If your car has climate control, adjust it to the minimum air temperature.
Check the supply of cold air through the interior grilles at idle and while driving.
Is there little or no cold when the engine is running at a standstill? Most likely, the external radiator is clogged with dirt and leaves and needs to be cleaned urgently. Otherwise, the freon in the tubes will overheat, the pressure will rise and a breakthrough may occur, or excess gas will be released by the valve into the atmosphere.
Stop the engine and open the hood. Find all components and pipes of the cooling circuit - receiver, condenser and compressor. You can distinguish the latter from the power steering pump by the tubes going to the radiator.
You can check the operation of the compressor's electromagnetic clutch without freon in the system and even without a drive belt. To do this, disconnect the standard connector from it and connect the contact with the positive terminal of the battery with a piece of wire. The clutch must engage and “tighten” the pulley so that the belt can rotate the supercharger axis.
Start the engine again, turn the system on in cooling mode and grab the thick tube leading from the passenger compartment to the compressor with your palm. Within 3-5 seconds. Once turned on, it should become icy. If this is not the case, then there is a lack of refrigerant in the circuit due to a leak at the connections or a broken radiator.
Carefully touch the tube connecting the blower to the condenser. When the outside temperature is up to 20 ° C, it should be warm, and during the heat it should be very hot.
Touch the thin line laid from the external radiator into the interior. It should not be very hot in any weather.
Finally, carefully inspect the joints and the visible part of the condenser for oil stains, indicating depressurization of the system.

Such testing cannot be called objective, because an ordinary car enthusiast may make a mistake. Therefore, at the slightest suspicion, it is worth visiting a car service as soon as possible.

Certain difficulties with diagnosing the air conditioning system arise in winter, when the electronics do not want to turn on cooling due to low air temperatures. To start it, you need to warm up the engine to operating temperature and heat the cabin as much as possible. Then the corresponding sensors will work and the air conditioner will turn on if it is working properly.

If, when buying a car, they tell you that the air conditioning system works, but the belt just broke or you need to refill freon, do not trust such a seller. You won’t be able to thoroughly check the cooler without a drive, so immediately negotiate to reduce the price of the car by 300-500 USD. e.

We find key elements and nodes of the system

It is best to check the car air conditioner yourself by sitting in the car for a while and feeling the temperature drop. As a rule, when you press a button, you can hear the click of the compressor turning on. At the same time, the fans should start operating, making a characteristic noise. It’s even better to bring an assistant with you for DIY diagnostics. As soon as he turns on the device from the passenger compartment, you should look under the hood of the car.

It is necessary to find a compressor that rotates with a drive belt. If the engine is started, then only its pulley will rotate, while the end part will remain motionless.

If you can hear a faint click when you turn it on, the equipment is at least working. But this will not be true for all brands of vehicles.

At the next stage of diagnosing the air conditioner, we will look under the hood for the air conditioner radiator with a tube and hose. The location of the radiator is right in front of the radiator, which directly cools the car’s power unit. Despite the external similarity, the air conditioning radiator is made of aluminum or copper.

A thick centimeter tube with a rubber hose inserted into it leads from the compressor to the air conditioner radiator. It may be equipped with a filling port, which is covered with a cap. The tube becomes thinner at the outlet of the radiator and leads to another device in the system: the receiver-dryer. On the top of the housing there is an inspection window through which we can see whether there is refrigerant inside.

Further movement of the tube is in the direction of the car interior. Despite the fact that it can follow curved paths, it all ends with a connection, after which it disappears inside the cabin. Another high pressure port can be installed in this area.

Visually inspect the place of entry into the salon. The thickest tube with a diameter of up to 2 cm will run nearby, which acts as a return line.

A low pressure port can be installed on it. It will also be useful to watch how to check the air conditioner in a car with your own hands, a video answering this question.

You may also be interested in: How to use an automatic transmission correctly

Video advice on how to check the air conditioner in a car with your own hands: