The situation when air conditioner makes cracks When on or in the process of operation, it is familiar to many car owners. This extraneous sound is not only irritating to the ear, but also serves as a reliable indicator that the climate control system has failed. Ignoring such acoustic signals can result in expensive repairs or complete failure of the compressor.
In most cases, cracking occurs due to mechanical wear of the moving parts or problems with the electrical component of the drive. Refrigerant It has nothing to do with it, because it moves silently on its own. Noise is generated by the nodes that make the system work. Understanding the nature of sound allows you to quickly localize the problem.
Next, we will discuss the main reasons why air conditioner cracksWe will look at the diagnostic methods available even in garage conditions. It is important not to panic ahead of time, as sometimes the reason lies in the little things that can be eliminated in a few minutes.
Problems with the radiator and condenser fan
The most common reason for which cracking under the hood is heard when the air conditioner is working is a malfunction of the cooling fan. When you turn on climate control, the system automatically starts. radiator to remove heat from the condenser. If there is a defect in the mechanism, you will hear a characteristic chirping.
Often the culprit is the bearing of the electric motor of the fan. Over time, the lubricant dries in it, and the metal begins to rub against the metal. Also, the impeller itself can emit a crack if it is unbalanced or touches the protective casing. A foreign object that falls into the rotation zone of the blades (branch, bag, wire) causes an instant and loud crack that cannot be ignored.
Diagnosis is carried out visually and by ear. Open the hood, turn on the air conditioner and listen to where the sound is coming from. If it cracks in the area of the radiator, check the cleanliness of the space between the radiator and the fan. Sometimes it is enough to remove the garbage to stop the noise.
⚠️ Warning: Never try to remove foreign objects or check the fan with your hands when ignition is turned on. The blades rotate at high speed and can cause serious injuries.
If there are no visual obstacles but noise persists, it is likely that the bearing or the entire fan assembly will need to be replaced. Prolonged work with worn bearings can lead to engine jamming and overheating of the car engine, as the cooling system will cease to function efficiently.
Failures of the electromagnetic compressor clutch
If the sound is coming directly from the air conditioner engine, the problem lies in the electromagnetic coupling. This assembly is responsible for connecting the pulley, which constantly rotates from the belt, with the compressor shaft. When the air conditioner is turned on, current is supplied to the coil, and a rigid clutch occurs.
A crack in this node often indicates an incorrect gap between the down plate and the pulley. If the gap is too large, the plate is pressed with a blow, causing a metal clang. If the gap is small or not at all, there is constant friction, accompanied by a screech and crackling, as well as the smell of burning.
Another reason may be the wear of the very pressing plate or the pulley surface. Over time, they become rough, which interferes with normal grip. In such cases, the plate may slip, emitting intermittent crackling, especially under load.
How do you check the clutch gap?
To check the gap of the electromagnetic clutch, a set of probes is necessary. The normal clearance is usually between 0.35 and 0.6 mm. If the gap exceeds the norm, adjusting washers are installed under the pulley of the clutch (behind the asterisk). If there is no gap or it is negative, the washers must be removed. Adjustment requires removal of the protective cover and often - dismantling of the compressor itself or removal of the belt.
To fix the malfunction, it is often necessary to adjust the gap with washers or replace worn elements of the clutch. In some cases, if the surface of the pulley is severely damaged, you have to change the pulley entirely or the compressor assembled. This is a critical node, and its proper operation directly affects the efficiency of the cabin cooling.
Wear of bearings and drive belts
The air conditioner compressor, like the generator or pump of the hydraulic power, is driven by a belt. There are straps and slings on the way. Exactly. roller-bearing often become a source of monotonous cod or hum, which is enhanced with increasing engine speed.
When the roller bearing begins to break down, it produces a characteristic dry crack. It can be distinguished from the noise of the compressor by the method of exclusion. Try briefly (literally for a second) splash water on the belt in the area of rollers. If the sound changes or disappears, the problem is in the belt or rollers. If the sound pattern has not changed, the source is deeper.
It is also worth paying attention to the condition of the belt itself. Coding can emit a worn belt cord, which begins to shag and touch the protective casings. A dried or overstretched belt can also make unpleasant sounds, although it is more often a whistle than a crackle.
☑️ Diagnostics of belts and rollers
Replacing rollers and belts is a planned and relatively inexpensive procedure. However, if you do not replace the collapsing bearing in time, the roller can jam. This will lead to the belt cutting, and the car will remain without charging the battery and cooling the engine, which is fraught with overheating in traffic.
Internal compressor breakdown
The worst scenario is when the crackle itself makes piston-engineer compressor. This indicates deep internal damage: wear of the piston group, collapse of the valves or lack of lubrication. In such cases, the sound is often accompanied by vibration of the air conditioning tubes.
The reason may be the leakage of freon along with the oil. Air conditioner compressors are lubricated with a special oil that circulates in the system together with the refrigerant. If the freon left, the oil settled in other nodes, and the compressor began to work "dry". Metal knocking and cracking in this case indicate that the knot is already irreversibly damaged.
Sometimes moisture or dirt gets inside the system, which causes hydroshock or abrasive wear of parts. Unlike clutch problems, the internal crack of the compressor is usually constant and does not depend on the clutch on-off cycles as long as the AC button is active.
⚠️ Warning: If you hear metal knocking from inside the compressor, turn off the air conditioner immediately. Further work will lead to the spread of metal shavings throughout the system, which will require expensive washing of all components and replacement of the radiator.
Repair of the internal mechanism of the compressor is possible only in specialized workshops and is often economically impractical. In most cases, it is necessary to replace the unit with a new or restored one. Also mandatory is the complete washing of the system and the replacement of the receiver-dehumidifier.
Comparative table of symptoms
To simplify the diagnosis, we collected the main symptoms in a table. Compare the behavior of your air conditioner with the described signs to narrow down the search for a malfunction.
| Noise source | Nature of sound | Dependence on the regime | Additional features |
|---|---|---|---|
| Fan | Crack, hum, beat | Appears when AC is turned on | Noise heard from the front, body vibration |
| Mufta | Metal clang, clicks | At the time of on/off | Smell of burns, bad cooling |
| Rollers/Shat belts | Dry crackling, whistling | Depends on engine speed | The sound changes with water spray. |
| compressor | Deep knock, grinding | Permanent AC operation | Tube vibration, metal shavings |
The use of this table allows us to weed out the obvious options. For example, if the sound only appears when the switch relay is clicked, then the problem is almost certainly with the clutch or electrician, not the bearings that make noise all the time.
The main task in diagnosis is to accurately determine the moment of sound occurrence: at start, constantly or when changing engine speeds. This narrows down the search for fault by 80%.
Electrical causes and relays
Do not discount the electrical part. Sometimes the crackling that the driver hears is actually making a noise. switch-on a compressor or fan located in the assembly unit under the hood. If the contacts of the relay are burned or the mechanism is stuck, it can emit frequent tapping or crackling.
Also, cracking can occur due to poor contact in the power connectors of electric motors. The sparkling of the contacts is accompanied by a characteristic sound and can lead to melting of the wiring. Check the integrity of the chips and the absence of oxides on the contacts.
In modern climate-controlled cars, the sound source can be a mixing servo product. If the gears inside the valve motor are broken, you will hear a torpedo cracking when you try to change the temperature or direction of the blower.
Try to disable the connector from the electromagnetic compressor clutch. If the AC button is turned on, the coding is gone, but the fan works - the problem is precisely in the clutch or the compressor itself, and not in the control electrician.
Frequent Questions and Answers (FAQ)
Can I drive with a cracking air conditioner?
Short term, if you are sure that it is not the internal knock of the compressor. However, prolonged operation with a faulty bearing or clutch can lead to a break in the belt and overheating of the engine. It is better to fix the fault as soon as possible.
Why does the air conditioner only crack on the cold?
On cold thickened lubrication in bearings can cause increased resistance and noise. Metal parts also have smaller thermal gaps. If the crack disappears after warming up, this may indicate the initial wear of the bearings.
How much does it cost to repair if the clutch cracks?
The cost depends on the brand of the car. Replacing only the bearing or adjusting the gap will be cheaper than replacing the coupling assembly. On average, repair of the clutch costs 2-3 times cheaper than replacing the entire compressor.
Will WD-40 lubrication help if the belt cracks?
No, WD-40 is not a belt lubricant and can even make things worse by dissolving the remnants of the factory stock. There are special air conditioners for belts, but if the belt cracks due to wear, only replacement will help.