Damaged And How To Fix Car Air Conditioning System

- Damage and How to Fix Car Air Conditioning System
Latest update date: February 08, 07

Air conditioning system is one of the most important components of modern cars, playing a key role in ensuring the comfort and safety of the driver and passengers. However, like any other complex mechanical part, the car air conditioning system can also encounter damage due to many different reasons.

Major system components such as the compressor, condenser, condenser, expansion valve, and refrigerant pipes are all likely to be affected, leading to reduced performance or even complete shutdown. entire air conditioning system. Early recognition of signs of damage such as unusual noises, unpleasant odors, or poor cooling ability not only helps ensure comfort during vehicle use but can also prevent serious damage. Moreover, saving significant repair costs for car owners.

Thanh Phong Auto would like to introduce the operating principles of air conditioning systems in popular car models such as Toyota, Mitsubishi, Ford, Honda, Chevrolet, Nissan or high-end car models Mer, Bmw, Lexus, Audi.... Common damages and how to fix them

How to fix damage to the car air conditioning system
How to fix damage to the car air conditioning system

Working principle of air conditioning system

The principle of operation can be summarized into the following steps: First, the compressor, connected to the engine via a belt, draws the refrigerant in the gas form (from the gas tank) and compresses it at pressure. high. When compressed, the refrigerant temperature rises and it is pushed to the heater, located at the front of the car, near the grille and has its own fan. In hot rigs, due to the heat dissipation at high pressure, the refrigerant turns into a liquid and switches to expansion valves (or throttle valves).

Operating principle of car air conditioning system
Operating principle of car air conditioning system

Next, at the throttle valve, the pressure drops suddenly so the refrigerant vaporizes and moves to the indoor unit. Here, it draws heat from its surroundings and causes the temperature to drop. Cold air will be blown into the cabin by the fan. The wind blowing from an indoor unit can be either external (external cooling), cabin wind, or both.

Basic structure of AC . air conditioning system

1. Compressor

The car compressor (refrigeration unit) is the most important detail that affects the operating process in the air conditioning system:

  • Create suction or create pressure reducing conditions at its inlet to recover hidden heat of refrigerant vapor from evaporator. This pressure relief condition allows the expansion valve or throttle to regulate the amount of liquid refrigerant to be sprayed into the evaporator.
  • Increasing refrigerant vapor pressure and temperature many times higher than ambient temperature helps to perform well the exchange process at the hot rig.
  • The refrigerant pump runs throughout the system.

The reasons that can lead to compressor damage include: compressor must always operate at large load, lack of lubricant, cold gas does not guarantee quality ....

Basic structure of AC . air conditioning system
Basic structure of AC . air conditioning system

2. Heater

The condenser consists of pipes and fins, and is installed in front of the water tank. The condenser uses a fan to reduce the high temperature and high pressure of the refrigerant compressed by the compressor.

The hot rig is responsible for converting the vapor refrigerant into a high temperature, high pressure liquid refrigerant (both steam and liquid gas).

In some models, the outdoor unit will be installed in front of the engine room. Therefore, when washing the car, the owner only needs to ask the person to clean the outdoor unit with water or with specialized chemicals.

Car air conditioner heater
Car air conditioner heater

3. Refrigeration unit

The evaporator evaporates the low-temperature and low-pressure mist refrigerant provided by the expansion valve, so it absorbs the heat of the air around the evaporator. The main damages in the evaporator are mainly air leaks, dusty air filters, etc.

Car air conditioner evaporator
Car air conditioner evaporator

4. Throttle valve

The expansion valve will regulate the amount of refrigerant injected into the evaporator, depending on the temperature in the vehicle. Dirt that sticks to the expansion valve tube for a long time will lead to blockage in the system.

5. Squirrel cage fan

The squirrel cage fan is responsible for bringing cold air from the indoor unit into the cabin. Depending on the design, the position of the air vents of each model, the squirrel cage fan is arranged by the car manufacturer with different numbers.

6. Dry filter

The dry filter (dehumidifier) ​​has the effect of removing water vapor in the medium, avoiding the situation where water freezes into crystals and destroys the system. In addition, the dry filter also has a filter that helps keep contaminants that may be present in the system. When the filter cannot retain moisture, it is necessary to replace the filter for the system to operate stably.

In the case of compressor replacement (cold cyclone), to ensure safety conditions for the whole system, extend the life of the cyclone, Thanh Phong Auto recommends that you also replace the capillary tube, dehumidifier and the whole rig.

Major failures on refrigeration systems

In the summer, the car air conditioning system is often used, so there are often abnormal incidents that make people not feel comfortable in the hot, stuffy atmosphere.

The environmental impacts affect the air conditioner.

Damp, dirt, air, rubber, metal debris and the wrong type of lubricant cause blockage, acid formation and reduce the cooling performance of the air conditioner.

Below, Thanh Phong Auto would like to present some major damages and how to fix them in the car air conditioning system:


Reason How to fix
Air conditioner indicates wind, not cold

– Lack of gas. If the amount of gas is not enough, the machine will only have wind but not cold or very weak cold.

– The air filter is clogged with dust.

– Gas pump, if not empty then need to remove the entire system to find the cause of the leak.

– Clean the air filter.

AC interrupts continuously

The gas pressure in the system is higher than the manufacturer's recommendations. When the system automatically detects abnormal pressure, the system will disconnect the air conditioner clutch to protect other parts of the system. Need to replace the new control valve, check the inlet sensor, which sensor should be replaced immediately.
Cold cling tape in car air conditioning system.

The air conditioning system is severely lacking of cold gas, the pressure in the tanks sharply decreases, leading to a significant reduction in the boiling temperature of the gas in the blown air, which will be frozen on the surface of pipes and openings. radiator leaves of the orchestra. Please clean, maintain, vacuum thoroughly, then add new gas.
The air-conditioning system works normally but has an unpleasant odor.

Because the cool ventilation system into the cabin (including the indoor unit, air filter, blower, air inlets and temperature sensor of the indoor unit) has become dirty or malfunctioning. Because car users leave the cabin dirty for a long time with impurities such as sweat, garbage, cigarette smell, perfume, food smell ... in the corners of the car interior. When the air conditioner operates and draws air into the cabin, those impurities will be discharged. It is necessary to clean the cabin of the car, cleaning the air filter with specialized interior cleaning chemicals. Air conditioning filters need to be replaced after every year or after years of installation.
The system leaked air, in the car only slightly cool

Because the vacuum process is not reached or the vacuum machine is weak, or when the gas is loaded, the air enters into the inside. This phenomenon you need to drain the gas, vacuum thoroughly. If this problem is not fixed quickly, the oil will be degraded, the concentrate will no longer be able to lubricate and damage the machine.
Damaged air compressor, condenser valve block. The car does not have cool air. Discharging the gas smells and the oil turns dark.

Due to a broken compressor (cylinder, worn-out piston creates gaps in the piston and cylinder, causing the phenomenon of not compressing enough pressure). In addition, the error is also caused by the stuck control valve, always open (high pressure chamber connected to control room). Need to replace compressor with or head case, the latter need to replace the condenser. In addition, when replacing the compressor, you need to replace the gas filter, cleaning the system to remove residue, oil inside, vacuum and gas intake.
Some signs appear on the gas control glass: Milky white color There is water in the system. Please clean, maintain, vacuum thoroughly, then add new gas, new oil.
Occasional bubbles or floating bubbles Lack of refrigerant (gas) or dehumidifier does not keep warm. Vacuum carefully, pump refrigerant (gas), change filter.
There are streaks of oil on the glass The system is free of refrigerant (gas). Refrigerant pump (gas)

Thanh Phong Auto gives some notes when using air conditioners

- You should turn on the A / C switch when the car has started the engine and turn it off before disconnecting the engine, otherwise it will damage the battery.

- Damage and How to Fix Car Air Conditioning System
- Should check and close the door when turning on the air conditioner and do not turn on the high cooling mode as soon as the car is moving, otherwise it will waste fuel and waste cold air out.

- Damage and How to Fix Car Air Conditioning System

- Need to adjust the most appropriate air-conditioning temperature compared with the current outside temperature.

– Normally you should let the fan take the outside air so that the car has oxygen, you should only get the wind while turning on the A/C so that the air inside is quickly cooled. Currently, some new cars have an automatic setting mode, after 5 minutes of taking the inside air, it will switch to the outside air intake mode.

In addition, the sensor can detect polluted air when passing through dusty areas, and will automatically switch to clear air. If your car does not have an automatic air intake setting, or has automatic but the sensor does not detect an unpleasant odor, you must automatically switch when needed.

You should periodically maintain your air conditioner on time at service workshops and professional garages to ensure your car's air conditioning system always operates in the best condition.

- Damage and How to Fix Car Air Conditioning System

- Damage and How to Fix Car Air Conditioning System

These are the shares that Thanh Phong Auto wants to send to the car users with the desire that the car users will better understand how the air conditioning system works in the car, and know how to maintain and repair damage. of that system.

Contact us for advice and support when experiencing the above symptoms! Thanh Phong Auto Proud to be one of the top reputable auto repair services in Ho Chi Minh City trusted by customers.

Frequently asked questions (FAQ)

1. How much fuel does the car air conditioning system consume?

The average car air conditioning system consumes about 0.2 - 0.4 liters of fuel/100km, depending on the vehicle type and usage conditions. At high outdoor temperatures (above 35°C), consumption can increase to 0.5 - 0.7 liters/100km.

2. How long is the maintenance cycle for the car air conditioning system?

The usual car air conditioning system maintenance cycle is 12-18 months or 20,000-30,000 km, whichever comes first. However, air conditioner gas should be checked every 6 months to ensure optimal performance.

3. How to increase the cooling efficiency of the air conditioning system?

To increase cooling efficiency:

  • Park in the shade
  • Use a windshield sunshade
  • Open the windows for a few minutes before turning on the air conditioner
  • Regularly maintain the air conditioning system
  • Use “air circulation” mode for the first 5-10 minutes

Read the article now: Instructions for using the car air conditioner properly & important notes to understand are shared on the website.

4. How to detect gas leaks in the air conditioning system?

Methods of detecting gas leaks:

  • Use electronic leak detector: Detect gas concentration in the air
  • Soap application method: Observe air bubbles at the joints
  • Using UV dye: Detect leaks under UV light
  • Check system pressure: Use a specialized pressure gauge

5. Why does car air conditioner smell bad and how to fix it?


  • Mold and bacteria grow in the system
  • Dirty cabin air filter
  • Standing water in the drainage system

How to fix:

  • Clean the air conditioning system with specialized solution
  • Replace cabin air filter (every 15,000-20,000 km)
  • Check and clear the drainage system
  • Use fan only mode for a few minutes before turning off the machine

6. How to save fuel when using car air conditioning?

Fuel saving measures:

  • Set the temperature at 23-25°C
  • Use “Eco” mode (if available)
  • Regularly maintain the air conditioning system
  • Avoid turning on the air conditioner when the engine has not started
  • Use cabin air recirculation mode
  • Turn off the air conditioning a few minutes before arriving at your destination

7. Should I refill my car's air conditioner at home?

You should not refill your car's air conditioner at home because:

  • Lack of specialized equipment (vacuum machine, gas scale)
  • Risk of overcharging or lack of gas
  • It is difficult to determine the exact type and amount of gas needed
  • Risk of damaging other components in the system
  • May be dangerous due to flammable gas and high pressure

View the article now: Be careful when recharging your car's air conditioner The correct way is shared by many experts in the industry.

8. How to protect car air conditioning compressor?

Measures to protect the compressor:

  • Regular maintenance every 12-18 months
  • Check and change compressor oil as recommended (30,000-50,000 km)
  • Maintain the correct amount of gas
  • Avoid turning on the air conditioner when the engine has not started
  • Use the correct type of oil and gas for the compressor
  • Check and replace drive belt as necessary

9. Why does car air conditioning work less effectively in winter?

Causes of ineffective air conditioning in winter:

  • Low temperatures reduce gas pressure in the system
  • Lubricating oil is thicker, reducing lubricating effectiveness
  • Seals and gaskets shrink, which can cause leaks
  • The system is rarely used, parts may be "off" for a long time

Solution: Turn on the air conditioner for at least 10 minutes every week, even in winter

10. How to choose a reputable car air conditioning repair workshop?

Criteria for choosing a reputable repair workshop:

  • Have certification and professional training in car air conditioning
  • Using modern equipment (vacuum machine, automatic gas filling machine)
  • Free diagnostic and quote services are available
  • Provides warranty for repair work
  • Use genuine spare parts or equivalent quality
  • Has good reviews from previous customers
  • Transparency about repair processes and costs

See article now: Top 9 Car air conditioning repair service in HCM Professional, best price, highly appreciated by many people today.

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5 Commentary

  • Huynh Tan Viet 01/06/2020

    2013 altis on the road were blocked AC air conditioner lights are not available, but running about 10km into the garage refrigeration check everything is normal, air conditioning is normal,
    Please advise this case.
    Thank you .

    • Miss Hue 24/06/2020

      Hi, you. This symptom is not clear, there are many causes, a follow-up test and a garage check back.

  • Nguyen decided 29/07/2020

    In my car, there is a lot of water flowing out but not deep cold. 16 degree heat clamp please ask the cause

  • Very useful article. I want Thanh Phong to advise: my car Honda City in 2017 has run 3 km, now there is a phenomenon that the air conditioner still works normally, but the water clings to the cold air conditioner, even though I have entered the test class. and clear the drain. Thank you for consulting Thanh Phong

  • Dang Dinh Hai 17/09/2021

    Inova2017 car for about 2 months did not start the engine, the car was not cold before, the air conditioner was still working normally, please tell me if it is out of gas

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