Hello everyone, our dear and respected car drivers! Every experienced driver who has devoted many years to driving cars and other vehicles can diagnose hundreds of breakdowns without ever leaving the passenger compartment. Any part that falls into disrepair disrupts the coherence of the entire automotive mechanism, and this, in turn, generates both external manifestations and sounds that indicate certain malfunctions. It can be sounds, vibration or failure of controls that refuse to perform their function. But the announcement by a car that something is faulty can be understandable not only to the driver himself, but also to passengers, and sometimes even to casual passers-by.

Not to be confused with anything that shrill creak issued. If he creaked or whistled, then your car will not be left without the attention of others, be sure. There is a misconception that such sounds emitted by the alternator belt are nothing more than a sign of its complete deterioration, which naturally requires the driver to replace it as soon as possible. But this statement is not 100% true.

An unpleasant sound can have another nature of its appearance. And in order to determine why the generator belt creaks, you need to thoroughly understand the structure of this "music" node.

Reasons for a squeaky alternator belt

Every vehicle, and most of its systems in particular, needs energy. The generator provided in the vehicle is responsible for the stable supply of it. The rotation of the generator rotor when the engine is running must be uniform and continuous, which is carried out thanks to the belt connecting it and. Pulleys are bolted to the crankshaft and generator shafts, connected to each other by a flexible ring - a belt that transmits rotation to the generator. The squeak of the alternator belt comes from this very mechanism.

By their design, pulleys and belts are different, but the principle of their relationship is unchanged. Based on the fact that the occurrence of a whistle or squeak occurs only with strong friction of parts against each other, it can be assumed that by loosening the tension of the alternator belt, the pulley will begin to slip. But there are several reasons contributing to friction, and therefore to the fact that the generator belt creaks. And here are the main ones:

- the belt is completely worn out and tension is simply impossible;

The belt is made of poor quality materials;

All sorts of fluids got on the alternator belt or pulley: technical, fuels and lubricants or cooling.

Diagnostics and elimination of the squeak problem

The main reasons for the appearance of a squeak are considered problems directly with the belt:its wear is nowhere to be found, low-quality material and its dirty surface. But it is not worth pushing back into the "back box" also checking some more details that are in direct symbiosis with the alternator belt: the pulley and the bearing, the roller mechanism of its tension. Let's take a closer look at what and how you need to check and what will be seen as a result.

We include Sherlock Holmes in ourselves and move along the path of the deductive method, that is, from the general to the particular. We open the hood and find the culprit of the heart-rending creak. We make visual diagnostics for damage, cracks and frayed edges. If these signs are found, then there is nowhere to delay replacing the belt and it is better to purchase an original part, because again you can make money for yourself headache because of a low-quality fake from the glorious "celestial".

Next, you should pay attention to contamination, which is also easily visually identified. If the alternator belt or pulley gets any kind of technical liquid, it should be cleaned if possible. Such elements interfere with its necessary tension and uniform movement. Better to replace in case of significant contamination.

If visual diagnostics showed that everything is in order with the belt, you should go to the mechanical nuances. Inspect the belt tensioner first. Each car has a different structure. With help this mechanism the tension level of the alternator belt is adjusted. You will read about what norm should be in the car passport. It is installed directly by the manufacturer himself. If the tensioning mechanism does not cope with its task to the specified level, then the wear is obvious and replacement is required.

But do not rush to conclusions yet, because you need to exclude another option - wear of the tension roller. What if he is the culprit, and not the alternator belt? Remove the belt and check if the roller is loose. If so, then you need to replace it. Also look at the generator bearing and pulleys, which should not be bent relative to the axis along which the belt moves, and of course should be clean.

If the alternator belt makes creaking and whistling sounds intermittently, and outside the window low temperature, for example, visual diagnostics of the mechanical part showed that everything is in order, the answer may turn out to be very commonplace. The material of the alternator belt is not endowed with sufficient elasticity characteristics, whether due to the weather or an unscrupulous manufacturer.

Replacing the alternator belt

Replacing the alternator belt is not difficult and even a novice motorist can do it. The wear of the alternator belt is, of course, a regrettable phenomenon, but on the other hand, it is a wonderful opportunity for a person who has just embarked on the path of a car owner to study the structure of his car and learn about the operation of its mechanisms using such a fairly simple example. Before replacing the alternator belt, make sure that it has indeed become unusable. In addition to the main symptom - the squeak, which we examined above, there is another one - this is the indicator signal that there are some problems with the alternator belt. It can signal both wear and its weak tension.

Typically, the alternator belt is located under the hood on the left side of the engine when looking at the vehicle. Before starting to inspect the alternator belt, you need to turn off the engine, remove the key from and disconnect the center wire from the battery. After that, you need to visually check the belt for wear, tears, cracks, loss of elasticity and elongation. If there are no visual problems with the belt and the belt looks pretty decent, then check its tension. Enough frequent problemthat occurs with the alternator belt is a weakening of its tension. Before replacing an old, broken belt, purchase exactly the same new one.

To change the alternator belt, first loosen the tension to help remove the old, worn belt. Use a wrench to loosen the tensioner bolt nut. But before that, first understand the tensioner device and find its location. Tension mechanism can be of two types: either a semicircular rail or a tension bolt. It depends on the car model. Before removing the old alternator belt, learn its location and method of engagement. Install the new belt in the same sequence. It will be possible to record the process of work in any way convenient for you.

If the tension on your car is adjusted with a bolt, then you need to choose a suitable key and turn it. Do not remove this bolt completely. Adjust the belt tension to your liking by loosening the bolt. Loosen it until the belt is taut enough to remove it as easily as possible.Compare both belts and make sure they are identical. Install a new belt also to prevent damage to the vehicle. To tension the new alternator belt, turn the bolt in the opposite direction. In the manual for your car, read about the optimal tension of the alternator belt. It should not be pulled tight. Do not forget just under the hood a wrench and connect the power cable back to battery... Then start the engine and load the electrics as much as possible, turning on everything possible at once, and turn off the gas. If there is still a squeak, tighten the alternator belt a little tighter.

What should be done to avoid the squeak of the alternator belt?

As a preventive measure for the alternator belt, it is good to use additives, namely the conditioner-tensioner in the form of a special spray. By treating the belt with such a tool, you will make it as labile as possible. He will enter his usual routine in a timely manner and will not annoy him with a whistle or creak. It acts like a skin cream. The generator belt will last longer, it will not crack soon, the main thing is to carry out preventive maintenance regularly and in a timely manner, because this part is very moody. And this "potion" is not so expensive as to suffer from belt creaks.

An unpleasant high-pitched whistle that periodically comes from under the hood of the car indicates a problem with the belt drive. As a rule, a loud squeak is heard when starting the engine or when pressing the accelerator pedal. And on idle and in the process of uniform movement, the sound does not appear. In most cases, you yourself will be able to determine why the alternator belt whistles "cold" and at the time of "unwinding" the engine. There are several reasons, and half of them are eliminated by the car owner.

Causes of problems

If you are faced with a similar phenomenon, then you probably noticed that the belt begins to emit an annoying squeak during the moments of greatest load. A whistling sound accompanies the rubbing of rubber against metal as a result of slipping of the belt drive. In 90% of cases, this indicates wear on the belt, which is a consumable and needs to be replaced periodically (interval from 20 to 60 thousand km, depending on the car brand).

Now more about the reasons for slippage:

1. Stretching during operation, loosening the tension. The element begins to sag, and with increasing loads, it starts to squeak.
2. Critical belt wear: the working surface is covered with cracks, threads come out on the sides, it is impossible to achieve normal tension.
3. You have purchased and installed a "consumable" made of low quality rubber. Such products stretch quickly, and the working surface is "licked".

Practice shows that low-quality products and fakes whistle even at maximum stretch. As they say experienced drivers, the material contains more soot than rubber.

Whistling often appears for other reasons that do not depend on the quality and technical condition belt:

• water or one of the process fluids - antifreeze, oil - has got on the working surface;
• worn out and began to wedge the bearing of the generator or tension roller;
• non-original V-ribbed pulleys are installed, whose grooves do not fit well with the profile of the belt, which is why it does not fit tightly to the surface.

In the design of some cars (for example, "Chevrolet - Niva"), the belt drive additionally rotates the shafts of the air conditioning compressor, the pump and the power steering pump. If the oil seal or the bearing of any of the listed units fails and grease gets on the pulleys, the belt will begin to slip and squeak.

Whistle when starting the engine

When one or more of the above problems occurs, the first whistle of the alternator belt appears when the engine is cold. This happens for the following reasons:

1. The cooled lubricant thickens and becomes viscous (especially in winter period), therefore, to turn the generator shaft, it is necessary to develop more force. A loose or worn out belt will slip and squeak at this moment.
2. If the drive rotates the power steering pump, compressor and pump, then the resistance of the thickened grease increases. A little slack or liquid on the pulley is enough for the belt to begin to slip.
3. At the moment of starting and the first minutes of engine operation internal combustion the generator has an increased load. The stator's electromagnetic field creates resistance to shaft rotation.

Cold squeak is the first symptom of a belt drive malfunction. If you do not diagnose the problem and do not take measures to eliminate it, the drive will also beep on a warm engine, at the moment the gas pedal is pressed.

Troubleshooting

Further, it is worth considering the question of what to do to the car owner with a whistling alternator drive belt. It is recommended to immediately inspect the mechanism and find out whether it is possible to continue moving or whether it is necessary to start repairs immediately. Diagnostics is performed as follows:

1. Open the hood, remove the plastic from the engine protective cover (if interfering) and carefully inspect the belt drive for water or process fluid. Sometimes the drive gets wet after driving through deep puddles.
2. If you find oily fluid, not only on the belt, but also on the cylinder block, try to find its source. Carefully inspect the pump, power steering pump and air conditioning compressor — all units located near the drive.
3. When inspecting, pay attention to the motor gaskets so that oil does not flow from under them.
4. Make sure the strap is not cracked and no threads are running up the sides.
5. Check the tension according to the car manual. A universal way is to turn the free section of the belt around the longitudinal axis. The tension is considered satisfactory when the element is rotated no more than 90 °.

If none of the above methods brought results, you will have to look deeper - loosen the drive belt and remove it from the pulleys. Then try turning each pulley by hand to find a shaft jam causing the belt drive to slip. If everything is in order here, carefully study the working side of the strap - the "licked" surface will make it clear that you have got a low-quality product.

An important point! Antifreeze leakage from the pump, lubricant from the engine or the power steering pump is considered a serious malfunction. After detection, you can only go to the garage or car service, where repairs will be carried out.

Remedies

Finally, a few words about how to eliminate the whistling of the alternator belt. The method depends on the cause of the malfunction:

• a worn-out element covered with cracks and not giving in to tension should definitely be replaced;
• if water or antifreeze gets in, wipe the drive parts thoroughly enough;
• traces of liquid lubricants must be removed with a rag moistened with a degreaser, and it is recommended to remove the belt in order to wipe the pulleys;
• loose belt drive.

Before removing traces operating fluids from the drive parts, it is necessary to eliminate the cause of their leakage, otherwise such work is meaningless. The leaking pump is changed entirely, and a new oil seal is installed in the power steering pump. If a seized generator bearing is found, then the unit will have to be dismantled and taken to an auto electrician for restoration.

A belt with a “licked” surface can be briefly extended using the old-fashioned method. Take a piece of solder rosin and rub your work surface well. The procedure is performed at idle speed of the engine in compliance with safety measures: rosin is applied to the inside of the rotating belt. After the operation, the element will gain adhesion to the pulleys, allowing it to ride without whistling.

All motorists and many pedestrians are familiar with the shrill whistle from under the hood of some cars, which is especially noticeable during acceleration. This whistle usually dies down when the car picks up the usual driving speed, but it causes discomfort not only for the driver of the car, but also for the people around him.

This whistle gives rise to the alternator belt, which has some kind of malfunction. Many people mistakenly believe that the only possible reason such a sound is the wear of the belt teeth, but in fact there can be many sources of such a whistle. Let's figure out what to do if the alternator belt whistles.

Why is there a whistling sound around the alternator belt?

The question of the occurrence of such a sound is of interest to many drivers. Particularly distinguished by such musical accompaniment are old cars that have already departed their resource. And it's not that the belt is installed a hundred thousand kilometers ago. The reasons for an unpleasant whistle from under the hood can be completely unpredictable.

It is worth understanding these reasons, because otherwise the car owner may constantly buy new belts and wonder why the sound does not disappear. In fact, a generator whistling belt problem can occur for the following reasons:

• liquid, gasoline or oil got under the generator belt (often the whistle passes quickly enough);
• the belt is worn out, one or more teeth are chipped, a crack has appeared on the belt body;
• a stronger belt tension is needed by repositioning the generator itself;
• one of the pulleys on which the belt works has changed its position - the belt unwrapping line is uneven.

This is just the beginning of a list of popular causes of alternator belt whistling. To detect a problem, it is enough to carefully study the node and get information about the correct operation of each element of this module. Sometimes the characteristic whistle is emitted not by the generator belt, but by the generator itself. In this case, the bearings are to blame, an urgent need to contact the service center.

Remember that replacing belts or even alternators may not always eliminate the annoying whistle. It often occurs for reasons beyond the control of the devices themselves.

How to examine the condition of the alternator belt and replace it?

While parked, open the hood, walk up to the left side of the car and, if necessary, unscrew the plastic case in which the alternator belt rotates. This will allow you to visually access the belt and examine it for damage. Often a whistle occurs due to a belt tear and its uneven travel, which also changes the tension.

In this case, it is enough to replace the alternator belt with a new one to get rid of the annoying whistle problem. The replacement procedure is as follows:

• buy a new alternator belt that fully meets the requirements of your car;
• remove all protective plastic covers for full access to the generator assembly;
• let the generator mounts so that it moves up freely and removes the tension from the belt;
• remove the old belt;
• put on the belt purchased in the store in the proper place;
• create tension with a generator and tighten the fasteners;
• then use a lever (preferably a wooden one) to finally tighten the belt and at the same time tighten the fasteners of the device.

If it is possible to perform this procedure with the help of specialists, it is worth doing this, because some cars require tensioning the alternator belt with a certain force. Handicraft work in this regard can significantly affect the quality of the car and make the return of the generator unit not the same as it is needed.

If replacing the alternator belt did not lead to the desired consequences and did not remove the whistle, then you will definitely have to contact the technical service and look for the problem more deeply.

Of course, in expensive and thoughtful japanese cars everything turns out to be much simpler, as in this video.

Video:

Summing up

Often times, alternator belt whistles can be heard from vehicles that clearly neglect regular maintenance. Remember that the alternator belt must be replaced in the car for a certain mileage. This mileage is determined by the vehicle manufacturer and is specified in the service requirements. If the replacement did not take place on time, the belt can perform its tasks for some time, but at some point it will certainly present unpleasant surprises.

It is quite possible to operate a car with a whistling alternator belt, but you need to understand the risks and inconveniences that such operation entails. Do you have the experience of driving a car whistling from under the hood?

Sometimes problems with a car can be detected by ear. One of the most common troubles is the whistling of the alternator belt. In some situations, such a characteristic sound is one of the symptoms wrong work the whole node. Today the alternator belt is one of the few ways to transmit crankshaft rotation to the alternator shaft and generate electrical energy. Alternator belt wear and problems can cause the vehicle to come to a complete stop at the wrong time.

What is a generator belt, its purpose and features

The alternator belt can be classified as one of the most vulnerable elements in a vehicle's design. Most of the consequences are not even caused by the breakdown of the main components, but by the neglect of control over lubricants, technical substances, maintenance of filters and anthers, and the alternator belt.

To date, the principle of operation of the alternator belt is considered one of the most reliable and simple ways communication between the crankshaft and the generator. Due to this simple technical design and low production costs.

Elastic tape, if broken or excessively worn, can immobilize the vehicle. To avoid such a problem, it is better not to neglect the timely inspection and replacement of the alternator belt.

The belt has a very heavy load when the engine is running. Therefore, a good part must meet all quality indicators: geometric characteristics, material of manufacture, certification.

For manufacturing, high-strength rubber (or other elastic material) is used, which is reinforced with polymer threads and laid from the inside with a multi-layer fabric base. Due to its complex structure, the belt provides excellent grip on pulleys and rollers without losing elasticity.

To ensure better grip, the belts have different shapes:

• Wedge. Tie one or two elements, designed for reverse fold. They are trapezoidal in section and can withstand very heavy loads.
• Serrated. In some cases, a similar alternator belt can replace the timing belt. Possesses excellent accuracy of transmission of the moment of movement. The structure has transverse slots.
• V-ribbed. Visually, they are distinguished by the presence of longitudinal grooves and a much greater width.

Diagnosing a Alternator Belt Problem

The main sign that something is wrong with the alternator belt is a specific whistle. Most often, it can be detected at the time of increased load on electrical systems car.

There is nothing critical or catastrophic in the fact that the belt began to whistle. However, you cannot ignore the appearance of uncharacteristic sounds. For example, if the whistle increases with increasing revolutions, the belt is weakened and the generator itself works worse than it should and does not fully charge.

It is much worse if the whistle does not disappear when the electrical load changes. Constant noise may indicate a need urgent repairs or replacement. To finally make sure of this, the belt must be inspected:

1. Visually, the tape should be intact, without scuffs and cracks.
2. The belt and pulleys must be free of grease and technical fluids.
3. The tension level should be normal.
4. The line of the two pulleys is positioned without offset.

Sometimes it is impossible to detect a problem during inspection, since the belt looks in perfect condition. However, this does not mean that there is no problem.

Sometimes the sound from the alternator belt appears during the cold season. The belt is too rigid, and therefore cannot cope with the transmission of torque. In this situation, the whistle will gradually disappear as the engine warms up.

If the belt mechanism vehicle there is a tension roller, then drivers need to monitor the condition of the bearing. Its wear provokes an unpleasant squeak, which can be eliminated by replacing the part.

Low elasticity, contamination and ingress of liquids

The alternator belt must be absolutely clean for proper and maximum efficient operation. The presence of dirt lumps puts a heavy load on the belt when it prevents it from moving evenly and maintaining tension. If during inspection it was found that dirt and dust adhered, you can risk cleaning the tape yourself. Perhaps using gasoline or additional funds. If it was not possible to clean the belt, the consumable will have to be changed.

A similar scheme applies if fluid is found on the belt. Most often to continue good work it is sufficient to remove drops of moisture or technical substances from the belt surface.

The opposite situation arises from constant or regular exposure to car shampoos, water, detergents and chemicals. Constantly in contact with the polymer structure of the belt, they dry out and contribute to cracking its surface. To protect the vehicle's operation, the alternator belt can be treated with a protective liquid. Its task is to maintain the elastic properties of the material and improve its performance.

It is best to resort to this measure for preventive purposes, in order to increase the resource of the element by 1.5–2 times. Such products are produced in the form of an aerosol.

Rough pulley line

Another cause of belt whistling is pulley misalignment. For proper operation, alternator pulleys and engine shafts must be in line.

To diagnose the problem, it is necessary to measure the level of the pulleys with a ruler. Elements are considered coaxial only if there are no gaps between the surface of the ruler and the pulleys. A similar problem can be corrected by eliminating the deformation of the attachment of the attached part using straightening or simply replacing the pulley.

If the alignment check is not possible due to a non-standard face or attachment, then the pulleys must be unscrewed. A thread or string must be pulled between the flanges. Next, we apply a ruler to the flange and, if the elements are parallel, two pulleys are on the same axis.

Tension problems, belt replacement

Motorists say that in 90% of cases, the cause of uncharacteristic whistling is insufficient or excessive belt tension. A special bracket is responsible for the degree of tension, and you can find out the norm for each specific car in technical data sheet vehicle.

A weak alternator belt tension reduces the efficiency of the alternator by an order of magnitude, which is why it does not generate a current of the required strength. In addition, this is accompanied by rapid belt wear. On the other hand, too much tension increases the risk of bearing failure.

To tighten the alternator belt, unscrew the nut that connects the alternator and the bracket. The lower nut must be loosened a few turns. To control and change the belt tension, you can slightly move the generator from the cylinder block. After all the manipulations, the nuts are tightened and checked - before starting the engine, several energy consumers (headlights or stove) are turned on. If the work is done correctly, the whistle will disappear.

To replace the belt, you need to repeat the same steps, only move the generating device until the belt is removed from the pulleys. After replacing, the engine must be allowed to run for a few minutes so that the belt fits correctly into its place.

Movie problem

If all the parts are visually normal, and the tension is adjusted correctly, then perhaps the problem lies in the mechanical parts. The whistling of the alternator belt will cause play or wear on the idler pulley, if provided.

To check it is necessary to inspect the peripheral space and remove the belt. The video itself must be tested for play, ideally, it should not be. If the problem lies in the tension roller, it must be replaced.

Belt wear and other reasons

In addition to the most common causes, unpleasant noises from under the hood can also cause problems with bearings, couplings or pulleys. Replacing the problematic part and timely technical inspection in the future will help to correct the situation.

On modern cars the generating unit, as well as its belt, have passed a certain stage of evolution. Most alternator pulleys are now equipped with a so-called -, which has greatly extended the life of these components. YES, and the belt drive itself is now not the same as it was, say 20 years ago, now there are so-called - which not only effectively engage and have a longer service life due to their structure, but also have greater efficiency. In general, 100 - 120,000 km this connection will not bother you! However, later problems may begin, as usually everything starts with a whistle, but there are also slipping gusts and so on. Today I want to tell you why this is scary, why it happens and how to fix the whole thing, as usual the video version will be at the end ...

Indeed, before, even on the VAZ 2101, the belt drive had to be checked almost every 15 - 20,000 kilometers, but now they go for 100 - 120,000 and many simply forget about this unit. Don't do that though. If your car has already covered 80,000 kilometers, you should look at this connection, because really with our climatic conditions it can fail and begin to emit certain whistles or even fly off.

Flew off, torn - what will be the consequences

At the very beginning, I want to answer - what will happen if the generator belt has fallen off? Highly frequent question to my website and channel. EVERYTHING IS SIMPLE - NOTHING WILL BE ! Often, a belt drive turns not only a generating unit, but also other units, for example a GURA pump, or an air conditioner pump, etc.

If it flew off or broke, then nothing terrible will happen! The power steering may stop working, the air conditioner and electricity will be generated, that is, the battery light will be on.

Can I go? Yes, you can, but NOT DESIRABLE! Because the battery will be discharged, the entire load will go to it, it will give its charge to the ignition and fuel pumping system, and how long it will last is DIFFICULT TO PREDICT! Because the state of the batteries is different for everyone.

The power steering will not work, that is, the steering wheel will become tight and it will be very difficult to turn it.

The air conditioning unit or climate control will not work, but this is not so critical here, I would definitely not turn it on with a torn or loose belt!

In general, the conclusion is that nothing terrible will happen, but you cannot go for a long time! Only to the nearest station, where the belt transmission will be restored again. However, there will be no global breakdown !!! This is not for you, everything can be much more deplorable there

Many people ask, if it whistled, then you need to carry a new one with you? YES, not always, it is corny, the pulleys are dirty or worn out, but about that a little later.

Why does it fly off?

Before talking about whistles, you need to figure out why it can simply slip off the pulleys. So:

• The generator itself is jammed ... It happens that the bearings get up and the armature does not rotate corny. Then it will fly off or tear in a few seconds, I have had this more than once in practice.

• Oil or diesel fuel flowing ... Gasoline is rare, yet it is not as oily as diesel fuel... But if diesel gets on the “canvas” (no matter what kind of oil or engine oil), then it starts to “absorb”, and as the masters say, “grow” in size. Often it becomes wide and disengages from the teeth of the generator pulley, well, it flies. In practice, I had such a case when the oil itself was changed, the filter was not tightened tightly and pressure was exerted from under it motor oil, and threw in the generator and belt. After some time, everyone noticed this, but the belt drive was already almost flying off, it was sitting on the wrong teeth, and its sidewall was worn out - they had to change, the filter was twisted. I also had to remove the generating installation itself and flush it, because oil oozed out of it and scattered it all over the engine compartment

• Weak tension ... But then he will whistle like "crazy", about this a little below
• It's time, wear ... Well, and of course the last wear of the belt itself, it happens that it has already "dried" cracked from time and can no longer keep its shape. There is only a replacement, and the sooner the better.

Why is it whistling?

For many, this manifests itself in the morning, as well as when you are on the gas, that is, as if under load. But it happens that the machine will work for a while and everything becomes normal, that is, the whistle - DROP!

YES, I want to warn you right away - if it does not disappear even on a "hot" or warmed-up engine, then everything can be much more deplorable, you should immediately go to the service station and DO NOT PULL!

Again, I will analyze the points:

• Water ... The simplest and most easily curable cause is water ingress. As we know, the belt unit is not covered by anything, there are no casings and covers, so if you do not have an engine crankcase protection, then water from puddles can easily get on it. Because of what he can whistle even on a hot one, although it only manifests itself for a few seconds or minutes. Then everything heals by itself. This can indicate a poor quality product or a weak tension - CHECK
• Ingress of liquids. As I wrote above, this is either diesel or oil. True, sometimes the belt may not make any sounds (more likely it will fly off corny), especially if ATF hit. But if a diesel fuel (engine oil) gets in, then it grows and begins to come out of the grooves, so you hear various sounds
• Distortions, tensioner wedge. There are special tension rollers, it is commonplace bearings and over time they can also "wedge" or wedge. The belt drive may not walk correctly, that is, not parallel to the plane of the pulley, will rub against them. So much for the whistle - and all the time! Urgently at the service station and look. True, in such cases, the belt will be heavily worn out, as if someone removes the shavings

• Overrunning clutch wedge ... The overrunning clutch in 95% of cases is attached to the anchor of the generator, it serves to damp shock loads on the belt drive, because our engine does not work smoothly, there are like burst cycles (when the fuel is burning in the cylinders) and gas evacuation cycles (then the opposite goes as if "falling"). So, if the anchor of the generating installation and crankshaft the engine will be connected rigidly, these abrupt cycles will act on the belt. And often on cars with clutches it will whistle or "whistle" not always, but almost constantly. It is also worth looking at the canvas, if it twitches, then the matter is most likely in the clutch.

• Pulleys ... There are only two main generators and a crankshaft (there are also pumps). It happens that they wear out corny, for example, the generating installation has the smallest pulley, the crankshaft has the largest, it turns out that the load goes exactly to the small one, and some manufacturers make them not from durable metals, but from an aluminum alloy, so the teeth are worn out, after which a whistle may be heard. I also had cases when the track itself is damaged, for example - there was a blow, and the teeth were crumpled. In any case, diagnostics and replacement are needed.

• Pollution. Dirt or stones get into the belt or pulleys. If you pull them out, then everything disappears. By the way, it is enough to clean the pulleys with a brush, from the dirt that has settled at the bottom. But this does not always "roll", often small stones damage the teeth either on a belt drive or on a metal surface
• Tension. From time to time, the belt drive can be pulled out, it happens mainly due to wear and tear, because the lower part is corny erased. You should tighten the connection (usually the adjustment can be up to several centimeters) and everything will pass. Do not pull very hard, the blade should have a stroke of 8-10mm in the longest section. But this already tells you that it will soon need to be changed.
• The belt itself is wear and tear. Again, there is wear and tear, you cannot run away from it, if cracks have started, if visually there is already a lot of destruction, then only change. It's not worth pulling