The summer heat turns the car interior into a hot oven, and the only salvation is a serviceable climate control system. However, it is at the time of peak load that many drivers are faced with an unpleasant situation: warm air blows from the deflectors or the cooling flow becomes barely noticeable. This is not just a sign of discomfort, but a sign that the system is climate-set There was a failure that required immediate intervention.
The reasons why the air conditioner stopped working can be many - from a banal lack of refrigerant to serious mechanical breakdowns of the compressor. Ignoring the first symptoms can lead to expensive repairs, since the lubrication system of the units directly depends on the circulation of freon and oil. In this article, we will discuss in detail the main malfunctions, methods of their diagnosis and ways to restore efficiency.
It is worth understanding that car air conditioning is a complex sealed high-pressure circuit. Any depressurization or ingress of moisture inside the system can disable expensive components. If you notice that the system climate control It works unstable, it is better to conduct a professional diagnosis immediately, rather than waiting for a complete failure of the equipment.
⚠️ Warning: If you hear a loud banging or metal grinding when you turn on the air conditioner, turn off the system immediately. Continued operation can lead to jamming of the compressor and destruction of the drive belt.
Freon shortage and violation of the tightness of the contour
The most common reason why the air conditioner is not cool is a banal decrease in the level of refrigerant in the system. Freon has a high penetrating ability and is able to escape even through microscopic pores in rubber pipes, not to mention poor-quality compounds. Annual loss of up to 10-15% of volume is considered normal for older systems, but if the level has fallen critically, the compressor simply cannot create the necessary pressure.
Often drivers wonder where the gas goes if there is no visible damage. The fact is that the sealing rings eventually dry up, and the vibration of the body contributes to the appearance of microcracks in the soldering areas of aluminum tubes. In addition, in case of an accident or a high speed collision, the cells of the condenser (air conditioner radiator) located in front of the main engine cooler can be damaged.
To diagnose the level of freon masters use gauge station. It connects to low and high pressure service ports and shows the real state of the system in statics and dynamics.
- 📉 The pressure in the system is below normal even after refueling is a sign of an active leak.
- 💨 Hissing when turned on may indicate a large rupture of the highway.
- ❄️ Freezing of tubes or nodes indicates the ingress of moisture in the circuit.
If the system has been operating with low levels of Freon for a long time, condensate could accumulate in it. Water reacts with oil and refrigerant, forming aggressive acids that corrode the metal from the inside. Therefore, a simple refueling without vacuuming and replacing the receiver-dehumidifier often gives only a temporary effect.
⚠️ Warning: Never try to just add gas without looking for a leak. Freon is not a fuel that burns, it circulates in a closed circuit. If it is missing, then there is a hole.
Failure of the compressor and drive mechanism
The compressor is the heart of the entire system, creating pressure and refrigerant circulation. If the air conditioner is turned on but does not cool, the problem may lie in the mechanical part of this unit. Modern compressors can be piston, rotary or spiral, and each type has its own vulnerabilities. Most often, valve plates fail or wear of internal friction pairs occurs.
Particular attention should be paid to the electromagnetic clutch, which transfers torque from the car engine to the compressor shaft. With wear pair or malfunction of the coil of the clutch may slip or not turn on at all. This can be seen visually when you switch on the button. A/C the characteristic click is absent, or the pulley continues to rotate freely, without dragging the inside.
It is important to monitor the condition of the drive belt. If it is pulled or, conversely, has too much backlash, it will affect the efficiency of the entire system. The tension must meet the manufacturer's specifications as specified in the manual.
How to check the work of the clutch visually?
Turn on the air conditioner and look into the under-hood space (exercise caution). The central part of the compressor pulley should start rotating along with the outer ring. If the outer ring is rotating, and the center is standing, the clutch does not turn on. If you hear a crack, the clutch slips due to wear.
Replacing the compressor is an expensive procedure that requires not only the installation of a new unit, but also the mandatory washing of the system. If the old compressor catches up with the shavings, it will fly through all the tubes and radiators, and the new unit will die after a few hours of operation.
Problems with the condenser and cooling system
A condenser (or condenser) is a radiator located in front of the main radiator of the engine. Its task is to cool the compressed compressor gaseous freon and turn it into a liquid. If the condenser is clogged with down, dirt, insects or leaves, heat exchange is disrupted. The pressure in the system increases dramatically, and the high pressure sensor forcibly shuts down the compressor to prevent an accident.
Often drivers forget that the efficiency of the air conditioner depends on the operation of the engine cooling fan. If the fan is not turned on at high speeds when the air conditioner is working (especially in traffic jams or idling), the pressure in the system will quickly reach critical values. This is a typical situation when the cold is on the highway, and in the city traffic disappears.
Mechanical damage to the capacitor cells is also a common cause of failure. Rocks from under the wheels in front of the cars easily penetrate the thin aluminum. At the site of damage, a leak begins, and over time, the freon evaporates.
- 🚿 Regularly washing the condenser with water under pressure (with caution) prolongs the life of the system.
- 🌡️ Overheating of the engine is often accompanied by failure of the air conditioner due to the common fan.
- 🛡️ Installing a protective net in front of the radiator reduces the risk of damage to the honeycombs by stones.
To check the efficiency of the heat sink, the temperature of the outgoing air from the condenser can be measured. It should be much higher than the temperature of the incoming air. If the condenser is cold or has uneven heating, this may indicate clogged internal channels with wear products.
System clogging and TRP malfunction
A thermoregulatory valve (TRV) or expansion valve is a device that doses the supply of liquid freon to the evaporator. This is where the gas expands and cools. If the TRP is filled with dirt, aluminum shavings or oil decay products, the circulation of the refrigerant is stopped. As a result, at the exit of the evaporator, we get warm air.
Clogging often occurs after improper repairs, when a new filter mesh has not been installed or washed into the system. Also, the culprit can be an old receiver-dehumidifier, which ceased to perform its function and began to collapse inside, clogging the system with silica gel granules.
A symptom of a TRP malfunction is often freezing of the tube at the exit of the evaporator or the valve itself. The ice blocks the passage section and the system stops cooling. After turning off the air conditioner and thawing, it can work again for a short time, but the cycle will repeat.
Symptoms of TRV clogging:1. Low pressure on the suction side.
2. High pressure on the injection side.
3. Plenty of condensate or ice on the valve body.
Diagnosis of TRV requires accuracy. Sometimes the problem is solved by replacing the filter element, but in most cases, the entire node is required to be replaced. It is important to use original parts or quality analogues, as the geometry of the valve needle is critical for proper operation.
☑️ Diagnosis before refueling
Electrical faults and sensors
Modern car air conditioning is not only mechanics, but also complex electronics. For its work is responsible for the control unit, which receives signals from a variety of sensors. If one of them transmits incorrect data, the system can go into emergency mode and stop turning on the compressor.
The most common failures are the Freon pressure sensor and the evaporator temperature sensor. The first protects the system from operating at critically low or high pressure. The second prevents freezing of the evaporator, turning off the compressor if the temperature on the honeycombs drops below zero. If the temperature sensor is lying and indicates that the evaporator is already cold, the compressor will simply not start.
It is also worth checking the integrity of the wiring and connectors. Vibration and moisture in the underhood space do their job: contacts are oxidized, wires are rubbed. This is especially true for the connector of the electromagnetic compressor clutch.
| Component | Symptom of malfunction | Probability. |
|---|---|---|
| Pressure sensor | The compressor doesn't turn on at all. | Tall. |
| Evaporator sensor | The air conditioner is turned off in 1-2 minutes | Medium |
| Fan relay | Noisy work, overheating in traffic | Tall. |
| Clutch safety | No clicking when switching on | Medium |
To diagnose the electrical part, a multimeter and, preferably, a scanner is needed, which can read errors from the climate control unit. Often the computer itself tells you which sensor failed, which greatly simplifies the search for a fault.
Service errors and improper refueling
Often the reason that the air conditioner blows warm air is not a breakdown, but poor quality previous maintenance. Many services sin by simply “pumping” Freon, ignoring vacuuming. The remaining moisture and air in the system create an "air traffic jam" that interferes with the normal circulation of the refrigerant and increases the pressure in the system.
Another critical mistake is the wrong amount of oil. The oil in the air conditioning system circulates with the freon and lubricates the compressor. If the oil is small, the compressor will jam from dry friction. If a lot of oil fills the heat exchangers (evaporator and condenser), drastically reducing the efficiency of heat exchange. As a result, the cold will be weak.
It is also important to use freon and oil strictly of the brand, which is specified by the manufacturer of the car. Mixing different types of oils (e.g. mineral and synthetic PAG) can lead to the formation of a thick substance that will clog the TRP and channels of the system.
⚠️ Note: The amount of oil in the system is measured to within a gram. Adding oil "by eye" or "how much is not a pity" is guaranteed to lead to the failure of the system.
After any opening of the air conditioner circuit (replacement of the compressor, tubes), be sure to change the receiver-dryer. Its sorbent is saturated with moisture from the air in a matter of minutes and stops working.
Quality refueling includes several stages: checking the tightness of the vacuum, removing moisture (boiling at low pressure), filling the oil and then dosed filling of freon by weights, not by pressure. Pressure is only an indicator, and weight is a fact.
Proper refueling of the air conditioner is impossible without vacuuming and accurate weighing of components. The savings at this stage result in re-repairs in a few weeks.
Frequently Asked Questions (FAQ)
Why does the air conditioning start to cool only after the car is dispersed?
The problem is probably with the condenser cooling system. On the move, the oncoming airflow cools the radiator, and the pressure drops to normal. In traffic jams or on idles, the fan can not cope, the pressure rises, and the sensor turns off the compressor. Check the operation of the fan and the cleanliness of the radiators.
Can I drive with an air conditioner that is not working?
You can drive, but it is not recommended for a long time. If the system is depressurized, moisture and dirt can get inside, which will lead to corrosion of internal components. In addition, the compressor can jam, and then you will have to change the drive belt, leaving without a generator and pump.
How often should I refuel my air conditioner?
A functioning system does not require regular refueling. If you have to refuel the air conditioner more than once every 2-3 years, then there is a leak in the system that needs to be found and fixed. Just “boosting” gas is a temporary and harmful solution.
Why does the air conditioner smell damp or mold?
On the evaporator, which is deep in the cabin, the condensate settles. If the drainage tube is clogged or after turning off the air conditioner do not dry the system (after driving a couple of minutes with the compressor turned off, but the fan is turned on), a fungus develops there. Antibacterial cleaning of the evaporator is required.