Alternator belt tensioner whistling

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During the operation of the car, the owner is faced with many problems, including an unpleasant situation with the alternator belt. He begins, seemingly for no reason, to “whistle”, and it is not so easy to immediately guess why this is happening. In our case, we are not talking about a worn or old belt. Everything is clear here - I replaced everything. No, everything is much more interesting, and, as in an exciting English detective story, we will look for a cause-and-effect relationship.

Inspect the belt and look for reasons why the belt whistles.

So, why does the new alternator belt “whistle”? As it turns out, there are several reasons for this and they are all presented below.

Briefly about the hanging belt

Belt drive is the most common method of transmitting rotation to the generator rotor. The method has been used for a long time and differs from others in its simplicity: only two pulleys on shafts that are connected by a belt.

The belt itself is responsible for a lot. It is he who is responsible for transmitting rotation from pulley to pulley. You should be aware that one part of the belt is tighter than the other . It is the difference between these tensions that determines the traction force and its coefficient.

The belt provides precise transmission and is quiet in operation. High-quality products are able to withstand long-term loads, smooth out shocks and jerks. They are compact, take up little space, but simultaneously operate several important components of the car: generator, pump, air conditioning compressor and power steering pump.

The generator rotor must rotate constantly. This is facilitated by the belt connection to the crankshaft. The pulleys, which are screwed onto the generator and crankshaft shafts, are connected by a belt, which must be flexible.

The “whistle” of the belt is similar to a disgusting clang. It is caused by the belt slipping. The sound of such a whistle is unpleasant and can be heard at a great distance. Of course, you should not drive in such a situation.

Debugg

Once the root causes have been identified, the troubleshooting process can begin directly. We stock up on time and tools. Now that everything is collected, we can begin. It is worth being prepared for the fact that parts will be required.

It is worth noting that for each specific make and model of car, the design features of the repair and location of parts will be different.

Therefore, it is recommended to first review the technological maps and study the design. Moreover, it is best to have a repair manual for the vehicle that will be restored.

Drive belts

Typically, a whistling sound in the engine, especially during a cold start, is associated with belt drives. Thus, a stretched belt slips along the pulley, which creates a characteristic squeak. Often, this effect is characteristic of the timing belt on newer cars. There are two ways to troubleshoot the problem.

The first way is to tighten the belt (only for cars with a belt and a tension pulley). To do this, you will have to dismantle the protective casing that covers the timing belt, and then tighten the drive using a tension roller. Sometimes it happens that the belt is in a very worn condition and requires replacement.

The second way is to replace the belt. Replacing the timing belt is a rather complex and time-consuming task. Therefore, it is recommended to carry out this operation at a professional car service center. Many motorists, unknowingly, when replacing the drive belt, knocked out the valve timing, which subsequently brought with it serious consequences for the power unit, such as major repairs.

For different car manufacturers, the timing of replacing the timing belt will be different, but the average indicator is that the element must be replaced after 40-50 thousand kilometers.

The process of replacing the timing belt is quite simple, but at the same time difficult to complete without knowledge of the design of the vehicle, as well as repair methods. So, let's consider the main provisions for replacing the timing belt:

To begin with, VTM labels are set. This is necessary in order not to disrupt the valve timing when replacing the belt.
The camshaft or shafts are fixed on pulleys to prevent rotation. There is a special tool for carrying out this operation, but as practice shows, motorists carry out fixation using improvised methods.
Next, loosen the belt by unscrewing the tension roller.
If necessary, on some car models, the crankshaft pulley is removed.
Remove the belt from the seats.
Typically, assembly of the unit is carried out in the reverse order. For many American cars, there is a specific sequence for installing the timing belt. Therefore, it is recommended to study the manuals before replacing.

Rollers

Together with the timing belt, the whistling noise may be caused by a worn tension roller. This is because the belt slides over the part, creating a whistling sound. The car rollers are replaced along with the timing belt.

On some cars, the rollers can be replaced without removing the drive belt. It is worth remembering that when changing an element, it is necessary to adjust the tension of the drive belt, because if this is not done, then very soon the whistle will appear again, and the belt will be subject to increased wear.

water pump

Many Lada owners are familiar with the whistling sound that appears after starting the engine when cold and disappears after warming up. This effect was caused by faulty pump parts. In both older and newer car models, the whistling effect can be caused by the water pump.

As with the timing belt, a squealing noise can be caused by a worn water pump belt. On older domestically produced cars, the pump is driven from the crankshaft pulley, while the gas distribution chain operates on a circuit installed directly in the block. For newer cars, the pump is part of the timing belt drive.

Belt whistling and its causes

Some motorists refer to the fact that the belt was allegedly of poor quality and replace it, but everything starts all over again. For this reason, in order not to waste valuable time and extra money, it is recommended to inspect the entire belt drive. Analyzing the conditions under which the whistle occurs is the most useful judgment a car owner can make.

The check comes down to the following steps:

the integrity of the belt is checked (we agree with the version that today even new products can be of poor quality);
the degree of tension is checked (as is known, belt squeaks often occur due to weak tension);
the cleanliness of the shaft is checked (another reason for the “whistle”, which is described in detail below);
the line of two pulleys is checked for displacement.

Whistle under various conditions

Note that the generator belt often whistles not constantly, but under certain conditions - after starting the engine, when creating a load, etc.

This, in turn, allows you to somewhat narrow down the search for the problem, but to do this you need to know which causes are the most common for certain conditions.

Cold and after replacement

Most often, the belt whistles after a cold start (after the engine warms up, the sound disappears) due to slipping.

Causes:

Relaxation of drive tension;
Padding;
Bearings if they contain inappropriate lubricant, which hardens strongly in the cold, which creates additional resistance to rotation, and after warming up it softens, and the problem disappears.

These conditions also include the complete jamming of one of the mounted units, but in this case the whistle will not go away after warming up, and smoke with the smell of burnt rubber will very quickly appear from under the hood.

Under load

The cause of extraneous sounds when creating a load is often insufficient belt tension, less often - its critical wear.

Increased load can be caused by the simultaneous inclusion of powerful electrical consumers or the connection of an air conditioning compressor, which forces the generator to operate at its maximum capabilities.

Usually, to eliminate the cause of the whistling, it is enough to first turn off one of the electrical consumers. Then visually inspect the flexible element for damage, check the condition of the bearings of the attached and auxiliary elements (just rotate them and make sure that they rotate easily and without jamming), and then correctly install and tension the belt.

In wet weather or rain

Another common condition under which alternator belt whistling occurs is rainy and damp weather.

Water that gets on the surface of the pulleys, in general, does not have any negative consequences for the belt. But in the normal state of the flexible transmission, squealing from ingressed moisture should not occur.

The whistle appears only when the working surface of the product is worn out and its adhesive properties are no longer sufficient to create the required friction force. In this case, the water acts as a kind of lubricant, due to which the drive element slips.

In general, the whistling of the alternator belt in rainy weather can be considered an audible indicator that the product has exhausted its service life and should be replaced.

Other reasons

For example, on older VAZ models, a V-belt is used, the working surfaces of which are the side surfaces.

So, if the pulley groove is very worn out, then the belt will sink into it more, because of this, the contact area of the surfaces decreases and it is easier for the flexible transmission to slip.

In multi-ribbed belts, this problem is not relevant, but there are other nuances.

Five main reasons why a generator whistles

Below is a list of the most common causes of alternator belt whistling:

Oil

gets on the belt

The provisions listed above are the main ones. But this does not mean that there cannot be other reasons. The most important thing is to respond to the problem in a timely manner and take immediate measures to eliminate it, then you will forget how the generator belt whistles.

You can recognize a certain type of malfunction in a vehicle by its characteristic sound. The most common problem, which even a driver without experience can identify, is the whistling of the alternator belt. Many people believe that if an unpleasant whistle occurs, it is necessary to immediately replace the belt. However, there are a large number of other reasons why the belt whistles and it is not at all necessary to replace it. Therefore, before replacing the belt, the driver must conduct diagnostics that will allow him to find the exact cause of the squeak.

The main causes of whistling

Tension force

Friction force is the main indicator in a flexible transmission. Weak or excessive tension has the same negative effect on adhesion properties. If the belt “sags” due to insufficient traction, it will slip, making a whistling sound.

As for the constriction, in this case the torque set by the crankshaft will prevail over the frictional force, causing loss of adhesion and slippage.

But it often happens that after additional tension, the sound does not go away; on the contrary, it may even intensify. And in this case, the problem is clearly different.

Drive wear

The second of the main reasons for belt whistling lies in the wear of the product. Delamination, cracks and chipped areas affect the tightness of the contact of the working surface of the drive to the pulleys, which is why slipping occurs.

The flexible transmission operates with large and variable loads, and the element itself is made of rubber, and although it is reinforced with strong threads, over time it stretches, wears out the working surfaces, breaks the threads, etc.

In addition, the material itself is damaged by environmental influences, which leads to aging and delamination of the rubber.

The average belt life on many cars is about 60 thousand km, but this depends on the operating conditions.

The ingress of technical fluids (primarily oil) also affects the friction between the working surfaces.

In addition to these problems, the drive may squeal for other reasons.

The sound is heard when starting from cold. Most often this happens due to poor-quality belt material or its natural wear and tear - “aging”.

For normal force transmission, a flexible drive must have good elasticity. But if hard rubber was used for its manufacture, then due to excessive hardness it will not properly “stick” to the surface of the pulleys, but will slip.

The same result is achieved by the “aging” of rubber; it becomes “tanned”, losing elasticity.

The reason may also lie in the bearings of the units that the belt drives, especially at subzero temperatures.

This happens because the grease in the bearings hardens due to frost, which increases the rotational resistance, causing the belt to slip along the pulley.

The squealing appears when a load is placed on the on-board network or when additional equipment (air conditioning) is turned on.

The reason lies in the same poor-quality manufacturing material, loss of elasticity, and deterioration of working surfaces.

If the problem appears only when a particular piece of equipment is turned on, this indicates a faulty bearing in that unit.

Contamination of the working surfaces of the pulleys

One of the conditions for the normal functioning of the drive is the cleanliness and quality of the surfaces with which it comes into contact. Dust and dirt falling on the surfaces of the pulleys act as an abrasive, increasing the wear rate of the working surface, and at the same time reducing the adhesion properties.

Scuffs, scratches and wear on the pulleys have the same negative impact. But the greatest harm comes from oil-based technical fluids coming into contact with pulleys or drives.

They greatly reduce friction forces, allowing the belt to slip over the surfaces of the pulleys. Also, rubber is very sensitive to such substances and because of them it “ages” and breaks down faster.

Therefore, it is important to periodically clean the engine and its attachments, and also ensure that there are no leaks of working fluids, and if they do occur, quickly eliminate them.

Incorrect placement of attachments

For normal force transmission, it is necessary that all pulleys are on the same line and strictly parallel to each other.

A slight misalignment of at least one of them or a protrusion forward relative to the others will negatively affect the contact patch of the belt with the surface, which will reduce the adhesion between them and lead to slippage.

Therefore, you should periodically check the reliability of fastening of all mounted units and the condition of their bearings.

Bearings of mounted units

Support bearings prevent axial displacements and ensure alignment of moving parts of equipment - shafts and rotors, reduce friction in units, so their condition directly affects the drive.

Their severe wear leads to the appearance of axial and radial displacements of the shafts (this is where the distortions of the pulleys and their protrusions relative to others come from); the bearings themselves can jam, creating additional counteracting force.

In addition, it is often they who make the squeal, but in tonality this sound is very similar to the whistling of a belt.

Therefore, when looking for the cause of extraneous sound, you should definitely check the condition of the bearings of the attachments.

Pulleys, shafts and rotors

During operation, not only the belt wears out, but also the pulleys themselves, albeit less intensely. But over time, traces of wear and tear appear on their working surfaces, which can affect the adhesion properties of the surfaces. The same situation applies to shafts and rotors.

In places where they contact the bearings, wear gradually appears, which causes backlash, and even the installation of new support elements does not solve the problem.

Changing the Physical Characteristics of the Drive

Negative environmental influences lead to rubber losing its elasticity (it “gets stiff”), which causes the friction force to decrease. At the same time, the belt itself may visually look like new and completely serviceable.

The most basic reasons for the appearance of whistling are listed above, but in reality there are more of them.

What is a generator belt?

The generator belt is installed to transmit torque to the generator rotor from the crankshaft. Due to this, electricity is generated, which is subsequently distributed among all consumers and for recharging the battery. To operate the belt, pulleys are used, and it is on them that the belt is put on to connect to the crankshaft.

In addition, a feature of the belt is its quiet operation. High-quality products can withstand heavy loads for a long time, while constantly smoothing out jerks and shocks. The belt sizes are small. For this reason, they do not take up much space. However, this part simultaneously sets in motion important structural components in the car, including the power steering pump, water pump, air conditioning and the generator itself.

How to eliminate timing belt whistling: step-by-step instructions

Trying to eliminate the whistling problem, some car owners use silicone lubricant or WD-40, which increases the elasticity of the rubber element and makes the fit tighter. At the same time, it displaces oils that cause slippage.

But this is not the most effective method - and it can even be dangerous if the teeth jump due to lubrication.

The cause of the whistling can be completely eliminated only by replacing the belt and roller, and the spare parts must be genuine and from a trusted manufacturer.

Popular brands:

Audi A8, BMW 7-Series, Mercedes-Benz C-Class

The actions take place in a car with the engine turned off in the following sequence:

On most models, it is recommended to remove the air pipe to allow more room for manipulation.
Next, the protective casing is dismantled. Most often, a 10mm socket is suitable for this.
The generator is mounted on two bolts that are adjustable in the grooves. Both clamps are loosened and the generator is moved towards the engine to relieve tension.
Its belt is dismantled. To do this, the right wheel of the car is jacked up, gear is set to 5th and, by rotating the tire, the drive is removed.
Using a socket head, the bolt holding the tensioner is unscrewed and the latter moves to the center of the internal combustion engine.
The old timing belt is removed and a new one is put on. In this case, it is important to pre-align the pulleys according to the marks (the specific position of the marks is indicated in the operating instructions for the car) to ensure synchronization of air compression in the cylinders and the supply of fuel with a spark and fresh air. If tension cannot be achieved, the crankshaft is turned by the jacked wheel.
Then use a roller to tighten the timing belt until it stops and fix the position.

Important! To begin putting the timing belt on the lower shaft first, and then on the upper.

Place the timing belt first on the lower shaft, then on the upper

After this, you should immediately try to start the engine (even before connecting the generator - the battery charge is enough for several minutes of engine operation) to see if the synchronization is correct. While everything is open, it is easier to correct something in case of an error. If the internal combustion engine does not start or runs on several cylinders, it is worth checking the position of the pulleys and starting again. When everything is normal, the belt drive is connected to the generator and the protective casing is installed. The generator is moved away from the engine with a pry bar to create tension, and its bolts are tightened.

Label option

Why does the driver hear a whistle?

When the power unit operates in a car, the belt, along with other drive belts, experiences maximum loads.

Most of the drive belts installed in the machine have a wedge shape, which provides a greater frictional force in the place where the part contacts the pulleys. Such elements even have appropriate names - V-belts.

These same products, but having several paths at once, called streams, are called polywedges.

Generator belts can be with or without teeth. It is generally accepted that products with teeth have a longer service life, since they wear out and slip less often.

So why is there a whistle? In 95% of situations, the manifestation of an unpleasant whistling sound occurs due to the friction of the belt on the pulley if slippage occurs. It turns out that when the belt is unable to turn the pulley, then it slips. This action is accompanied by a sound resembling a whistle.

The motorist should not look for the cause of the sound, but for faults that cause the belt to slip.

There may be several of them:

Weak and, conversely, very tight tension of the generator belt. Over time, the belt may stretch. The main reason for this is wear and tear of the lower part of the part. The car owner will only need to tighten the connection point. However, it is important to remember not to tighten it too much. In the longest section, the blade should have a stroke in the range of 8 - 10 millimeters. A belt that is too tight can also cause a squealing noise. It is no secret that extremely tight tension does not allow the pulleys to rotate normally. This situation often occurs in winter. The squeak disappears from the moment the engine reaches operating temperature and the belt takes its previous shape.
Poor quality or temporary wear of the belt. Often, the material used in the production of the belt itself is not the same material applied to the outside of the product from Chinese manufacturers. When the top layer wears, the belt makes a squeaking sound. If the wear is too great, then even the next tension will not help eliminate the problem with the belt whistling. When cracks appear on the product or traces of major destruction can be visually detected, the problem can be corrected by replacement. There is no point in delaying this issue, since such a belt can break at any time.
Contact with the pulley or belt of technical fluid used in the operation of the machine, for example, oil, washer fluid and even plain water. Problems with whistling appear most often due to contact with engine oil. The belt loses its previous grip and slips with the appearance of a characteristic sound.
Malfunction of the tension roller or generator bearing. A technical problem with the bearing can cause an unpleasant sound emitted by the hanging belt. The owner of the car will only need to replace the bearing. This structural unit also has special tension rollers. This part is a type of bearing that can begin to seize over time. Because of this problem, the movement of the belt drive is disrupted, the belt rubs heavily against the pulley. In this situation, the belt will show signs of severe wear. The car owner must inspect the mechanism, remove the belt and check the play of the rollers.
Axle mismatch between pulleys. The appearance of a nasty whistle may be due to misalignment of the line between the two pulleys. The pulleys must be positioned strictly on the same axis, and even a slight slope can cause a whistle.

There are several pulleys in a car. The first is located on the crankshaft, and the second on the generator. With constant use of the car, the pulleys wear out. A small pulley is installed on the generator; on the crankshaft, on the contrary, the largest one is installed. Most of the load will go on the small pulley. Some automakers make a small alternator pulley from not the most durable materials. Therefore, wear of the teeth on this part is a matter of time. In addition, situations often occur when damage occurs on the track itself, for example, after an impact.

In any case, the car owner will need diagnostics and replacement of damaged parts.

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Belt drive and its features

A flexible belt for transmitting torque to power unit attachments has become widespread for a number of reasons.

The product itself is quite flexible and durable, which allows it to be placed between many elements arranged in different orders. This type of power transmission is characterized by quiet operation, low cost and a fairly long service life.

But it was not without its drawbacks. This drive requires the correct arrangement of the elements to which it transmits force; it is quite sensitive to aggressive influences and the quality of the pulley surfaces and their distortions (if installed incorrectly).

If at least one of the conditions is violated even slightly, the belt immediately signals this with a loud and unpleasant whistle (squeal) or squeaks.

The forces here are transmitted due to friction forces, and to ensure maximum traction torque, not only a certain degree of tension is required (which ensures adhesion to surfaces), but also minimal resistance to the transmission of moments.

Due to wear and damage, friction occurs on the pulleys of the units and on the belt, which makes it difficult for the moving parts to rotate, which in turn affects the transmitting torque.

Due to the large opposing force, the belt begins to slip along the surface of the pulley, which is accompanied by unpleasant sound effects.

Therefore, if the generator belt whistles, you should not immediately change it, but you should first establish the cause of the sound, and there are many of them.

Why does the belt whistle when cold?

The problem of whistling when cold can have several varieties. A squeak or whistle does not appear when the engine starts, but after a couple of minutes. This problem is easily diagnosed, since after the engine reaches operating temperature, the sound disappears.

The reason for the non-standard behavior of the belt is also hidden in its slippage. The torque transmitted from the crankshaft is not sufficient to spin the pulley. There are several reasons for this problem:

Inaccurate selection of bearing lubricant for the generator. Due to the compaction of the lubricating fluid consistency at low temperatures outside, the generator pulley is not able to function as usual until the machine’s power unit warms up. At engine operating temperature, the lubricant will defrost and the unpleasant sound will disappear. The solution to the problem will be for the car owner to purchase a lubricant option that is more resistant to temperature changes outside the window.
Weak tension. This situation is identical to the previous one. Until the engine reaches the required operating temperature, due to low tension, the belt is not able to perform its functions at the required speed and will slip.

How to remove the whistling of the alternator belt

To eliminate belt whistling, you first need to determine the reasons that cause the alternator belt to slip.

The slippage problem is accompanied by an unpleasant whistle, and it must be eliminated in this order:

The engine is switched off, the hood is opened and locked.
The belt is carefully inspected, and there is no need to remove it from the pulleys. The surface of the part must be free of tears, loose threads and other damage. If signs of wear are detected, the part should be replaced.
Both sides of the alternator belt should not be wet, with traces of dirt, or signs of ingress of any technical fluids used in the vehicle. It's the same with pulleys.
Check the tension value of the part, because most often the whistle from under the hood is due to a loose belt. You can find information about the required alternator belt tension parameter for any car model in the included factory instructions or on the Internet.

If these actions are not successful, a whistle is still heard from under the hood, you can start the engine and, in good lighting, visually check the alignment of the pulleys.

A clear sign of misalignment is the moment when the poly V-belt jumps between tracks and slides off the pulley.

Attention should also be paid to nonlinearity during pulley rotation. If one of these parts draws a figure eight when rotating, over time it will either reset or tear the alternator belt. This behavior is typical for pulleys with a rubber damper. This material quickly loses its former elasticity and does not fulfill its duties.

When, even after all the above steps, the problem does not disappear, then you should look for a solution either in the belt itself or in the structural elements driven by it. The reason may be hidden from the car owner in thickened lubricant of the bearings or their failure.

You can eliminate the nasty sound of the alternator belt for a while using special auto chemicals. For example, an air conditioner tensioner will help eliminate the problem for a short time. Auto chemicals will not help completely eradicate whistling, but the driver will ensure silence for a while.

Sometimes car problems can be determined by hearing. 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 of malfunction of the entire unit. Today, the generator belt is one of the few ways to transmit crankshaft rotation to the generator shaft and generate electrical energy. Alternator belt wear and problems can cause your vehicle to stop running at the wrong time.

It's not necessarily a belt: what's whistling under the hood and what to do about it?

From simple to complex

Let's start with the belts.
Whatever one may say, most often they are the ones who really whistle. Of course, the timing belt cannot whistle - it is toothed, but all other accessory belts (drive or service belts - as you like) can whistle very loudly. The reason for the whistling may vary. Firstly

, a weak belt tension may be to blame. It's too obvious and simple.

Secondly

, the belt itself is getting old. Over time, it “dumbs” - loses elasticity. Such a belt can no longer fit well enough to the pulley and begins to slip, even if everything is in order with the tension. And if, on top of everything else, it is also “eaten” by tens of thousands of kilometers, then a whistle will definitely appear.

Third

, the belt may simply be dirty. Here you need to figure out why it is dirty. If the car does not have normal protection from below, then everything is clear: water, sand, dust - all this settles on the belt. And if the water dries out quickly, then the same sand cannot dry out, but it’s easy to gnaw out the rivulets of the belt.

It also happens that something from the car leaks onto the belt: oil, antifreeze or brake fluid (the latter, of course, is unlikely, but still). And while antifreeze or brake fluid most likely won’t do much harm, motor oil is a rather aggressive thing that corrodes the belt material. If the belt is covered in oil, it must be replaced. And, of course, only after the cause of its spraying is found and eliminated.

Since not only the belt can whistle, you will also have to make sure that it is the culprit of the squeal. The easiest way is to spray water on it. If the belt has simply become stiff from age, then a little help may help. Or maybe not, because if he is weakened, then the whistling will become even stronger. But at least you can understand from the change in sound that something is wrong with the belt. This is especially convenient if there is more than one drive belt: water will help you find out which belt is whistling. Well, if it doesn’t work, then nothing terrible will happen: the water will simply dry up. With the currently fashionable belt sprays, the situation is more complicated.

Theoretically, these sprays are designed not so much to diagnose the problem as to solve it. The spray usually contains a fun ingredient like pine tree resin. Resin is nothing more than ordinary rosin, which costs 20 times less than a spray. True, it is difficult to apply it to a belt, but the principle of action is exactly the same: increasing friction. The spray also contains alcohol, which can soften the belt a little. It seems that the recipe is perfect: the hardened belt gains elasticity, and the resin increases friction. But life is not all so rosy.

No one knows how long an old belt will last after treating it with alcohol. Maybe it will break in a couple of days? Anything can happen. Well, rosin is even worse. Yes, it will be much better for the belt to stick to the pulley. But the spray forms a sticky layer on the inner surface of the belt, which attracts not only the pulley, but also all the rubbish from the road: dust, sand and everything else. All this also greatly reduces its service life. As a result, the spray has an effect, and sometimes it can really help out. But it’s not worth spraying it on your belt endlessly. Therefore, I would classify this spray primarily as a diagnostic tool, not a repair tool. If it helps, then you need to change the belt (and at the same time you need to clean the pulley grooves from resin). Repairing a belt with this chemical is like going to the Statue of Liberty every day with a bouquet of roses, hoping that she will throw away the torch, accept the flowers and kiss her on the cheek.

You can also spray regular Vedashka on the belt. If the whistle disappears, then it is the belt that is whistling, and not something else.

Belt, but not the same one

The most likely and at the same time difficult to diagnose cause of a whistle from under the hood is a slipping alternator belt. The most likely is because it is very difficult for the belt to turn the generator, especially if a large number of consumers are turned on. In this case, the rotation is prevented by the increased resistance of the magnetic field, so if a whistle occurs when powerful consumers are turned on (for example, a heated windshield), then the cause of the whistle is definitely the generator belt. Another way to check for a whistling sound from the alternator belt is to sharply press the gas and release it sharply. If it whistles precisely when the gas is being released, as a rule, the reason is in the alternator belt. Of course, this method only makes sense on machines with multiple belts. If there is only one belt, then it whistles, everything is clear here.

The difficulty of diagnosis lies in the fact that sometimes it is not so much the belt itself that is to blame for slippage, but rather the thickened lubricant of the generator bearings. This is especially true now - in winter and in the cold (who already has it this winter). So if the belt still looks good, the deadline for replacing it according to the regulations has not come, but the whistle is still there, then you will have to think that the reason is not in it, but in the generator. However, a short whistle after starting in cold weather is not critical. The main thing is that it disappears within a few seconds.

What if it's not a belt?

Unfortunately, the belt is the lesser of the evils that can whistle and squeal. Anything driven by a belt spins. And if it spins, it has bearings. And here there is a difficulty: to determine which bearing is whistling. Rollers (tension and parasitic), power steering pump, water pump, generator, air conditioning compressor... A lot of things can whistle there. How to find?

The most consistent ones start by resetting the drive belt. If, for example, a whistle or squeak remains, then we look at what can “sing” from the timing belt. These could be the rollers of the belt itself, or maybe the pump, if it is driven by this belt.

If the whistle disappears, the belt is good and does not react to being sprayed with Vedashka, water or spray, then we are looking for the unit that makes the nasty sound. Here the methods are different. The simplest is to pump all the pulleys and rollers by hand, trying to detect any play. Sometimes this method works, but in this case the bearing wear must already be very large. Or maybe it’s almost gone, and the reason is again thickened or missing lubricant. Then this method will do nothing.

The second way is to use a stethoscope. Not everyone has one, but if desired, it can be made from an old medical phonendoscope and a piece of suitable thick wire (nail, electrode - any metal rod of suitable diameter). Well, if this is too difficult, then a universal diagnostic device called a wooden stick will do. The device is simple, but very effective. The only pity is that you have to get used to it. So, we take any wooden stick (preferably from hard and dry wood, a piece of wooden plinth, a shovel handle - anything, but with one sharpened edge will do), and place one end of it against the axis of the roller, and the other, clamped in a fist, to the ear. And we listen.

It is impossible to make a mistake with a stick, but there are two very important notes: sometimes it is difficult for it to get to the desired roller (often it is completely impossible) and if you poke the stick anywhere, you can put it under the belt. In the best case, it will tear, in the worst case, it will manage to injure with a stick the one who puts it in the wrong place. So you need to use the stick wisely. The method is very garage and old-fashioned, and is not suitable for everyone.

What to do with rollers and bearings is something everyone decides for themselves. Sometimes it is actually enough to update the lubricant, and sometimes only replacement helps. The main thing is to do it on time. Imagine if on your car one belt turns both the pump and some kind of generator. If the belt breaks, you can drive 50 kilometers home without charging, but you won’t be able to drive without a pump at all. So it's better to be safe here.

Do no harm!

It’s not for nothing that they say that the best is the enemy of the good. It happens that in an attempt to eliminate some non-critical malfunction they only make things worse. Trying to tighten the belt is one such operation that can lead to some collapse.

The belt tension is not taken from the ceiling. If the belt is tighter than it should be, it slips. And if it is stronger, it significantly reduces the life of the rollers and bearings of the units. The tension must be strictly set by the factory. If the belt looks like a stub, then you should not tighten it. Most likely, it will continue to whistle, but at the same time, with a high degree of probability, it will turn aside some other bearing that is still quite working.

You should not try to tighten an old belt, the service life of which is coming to an end. Outwardly, it may still look very decent, but its material already loses its elasticity from old age and cannot grip the pulley well. In this case, excessive tension will also only cause harm.

The same applies to analogues of all kinds of lousy things. It is clear that paying three thousand for some original belt instead of five hundred rubles for an analogue is stepping on one’s own throat. But in this case, you need to be prepared for the fact that it may also serve less. Not always, of course, but quite often.

And another reason for the appearance of whistling is pulleys of unknown origin. They are changed rarely, but sometimes not very accurately. There are usually two mistakes: they made a slight mistake with the diameter or – which also happens – with the number of rivulets. Diameter is not only tension, but also a changed gear ratio, which the belt may not be able to cope with and may slip. But a pulley with five streams instead of a pulley with four is usually a sign of garage collective farming. Here, not only can the load on the bearing change, but the belt can also warp during installation. In this case, the whistle will be very persistent.

And finally, the last thing. Extraneous sound from under the hood can appear not only for a mechanical reason - due to belts, rollers or bearings. The diode bridge of the generator can also “sing” its songs. Sometimes a blown exhaust manifold gasket whistles. At an early stage, the sound will also be whistling.

In general, if you want to train your hearing, listen carefully. And if nothing works, then go to the service center. By the time this “good” sound comes out on its own, it may already be too late.

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What is a generator belt, its purpose and features

The alternator belt can be classified as the most vulnerable element in a car's design. The biggest consequences are caused not even by breakdowns of the main components, but by neglect of control over lubricants, technical substances, care of filters and boots, and the generator belt.

Today, the principle of operation of the alternator belt is considered one of the most reliable and simplest ways to connect the operation of the crankshaft and the generator. This is due to the simple technical design and low production costs.

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

When the engine is running, a very large load is placed on the belt. 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 lined from the inside with a multilayer fabric base. Thanks to its complex structure, the belt provides excellent adhesion to pulleys and rollers without losing elasticity.

To ensure better grip, the belts have different shapes:

Wedges. They connect one or two elements and are intended for reverse bending. In cross-section they have a trapezoidal shape and can withstand very heavy loads.
Serrated. In some cases, such an alternator belt can replace a timing belt. Has excellent accuracy in transmitting torque. The structure has transverse slots.
Polycline. Visually they differ in the presence of longitudinal grooves and a significantly larger width.

What can you do?

As you can see, the main reason lies in the drive element itself, therefore, when third-party sharp sounds appear, you must:

Check the belt tension and adjust it if necessary.
Assess the condition of the working surface of the drive element (there should be no cracks, delamination or other defects).
Check the tension roller (play and jamming during rotation are not allowed).
Diagnose the condition of attachment bearings for play and wedging.
Removal and detailed inspection of the flexible element for damage, delamination, and traces of technical fluids.

You can do the listed work yourself, but if you have difficulties with self-repair, compare at https://autoreshenie.ru/zamena-remnya-generatora-711/ the prices for replacing the alternator belt among all car services in Moscow, read the reviews on them and pick the closest one!

Many car owners note that unpleasant third-party sounds appear only under certain conditions or after replacing the drive element. It is noted that the belt tension is normal, but there is a whistle.

This is usually due to poor quality of the product and its increased hardness.

To solve the problem, you can use two methods - change the alternator belt to a high-quality one or try to treat it with chemicals.

Diagnosis of 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 a time of increased load on the vehicle’s electrical systems.

There is nothing critical or catastrophic about the fact that the belt began to whistle. However, the appearance of uncharacteristic sounds cannot be ignored. For example, if the whistle increases with increasing speed, the belt is loose and the generator itself is working worse than it should and is not fully charging.

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

Visually, the tape should be intact, without scuffs or cracks.
There should be no traces of grease or technical fluids on the belt and pulleys.
The tension level should be normal.
The line of the two pulleys is located without displacement.

How to eliminate the squeaking of the alternator belt with your own hands?

To check it, you need to press the product between the generator and crankshaft pulleys somewhere near the middle.

Checking the tension of the product The deflection should be in the range from 6 to 8 mm. If the tension is not correct, it needs to be adjusted. If the tension is poor, the unit does not produce a full charge.

To tension you need to do the following:

Open the car hood.
Loosen the generator mounting nut.

Generator mounting nut

After this, the mechanism takes its original position, due to which the product weakens.

Low elasticity, contamination and liquid ingress

For the alternator belt to operate correctly and as efficiently as possible, it must be absolutely clean. The presence of dirt balls puts a lot of stress on the belt when it prevents it from moving evenly and maintaining tension. If during inspection a build-up of dirt and dust was found, you can risk cleaning the tape yourself. Perhaps using gasoline or additional means. If it was not possible to clean the belt, the consumable will have to be replaced.

A similar scheme operates if liquid is detected on the belt. Most often, to continue proper operation, it is enough to remove drops of moisture or technical substances from the surface of the belt.

The opposite situation occurs due to 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 of its surface. To protect the operating process of the car, 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.

Lubricants

To lubricate the alternator belt, use only approved fluids.

Below are several types of them:

LIQUI MOLY KEILRIEMEN-SPRAY is a product for treating V-belt and poly-V-belt drives. The manufacturer claims that this spray increases elasticity, improves traction properties and reduces the likelihood of slipping, protects rubber from negative influences, increasing service life, increases the overall efficiency of flexible transmission, and eliminates squeaks.
HI-GEAR BELT DRESSING – spray conditioner for drive belts. The product allows you to improve the adhesion properties of flexible gears, increases their service life by 1.5-2 times, protects against drying out and cracks, and reduces noise.
VERYLUB is a spray product designed to care for belt drives. The liquid cleans working surfaces well from dirt, eliminates slippage, and protects from negative influences.

The above are some of the most common means for lubricating the generator drive, but there are many other options on the auto chemical market:

Weicon;
LOCTITE 8005;
Forch P325;
Gunk M206;
Permatex PR-80073;
ABRO;
PITON
Wurth.

All of these products are inexpensive, but can really help eliminate unpleasant sound.

Silicone lubricant in the form of a spray for treating rubber elements and the Hi-Gear conditioner have proven themselves to be effective.

The use of these means increases the elasticity and “sticking” of the drive to the pulleys.

But the use of WD-40 for these purposes is not recommended. This spray contains petroleum products that can have a negative effect on rubber and lead to its rapid aging.

This treatment can really help eliminate whistles under the hood, but only temporarily, and after a certain period they will return again. Therefore, only replacing the alternator belt will help you get rid of third-party sounds for a long time.

Uneven pulley line

The next reason for belt whistling is misalignment of the pulleys. For proper operation, the generator pulleys and engine shafts must be in line.

To diagnose the problem, you need to use a ruler to measure the level of the pulleys. Elements are considered coaxial only if there are no gaps between the surface of the ruler and the pulleys. This problem can be corrected by eliminating the deformation of the fastening of the hinged part using straightening or simply replacing the pulley.

If it is not possible to check the alignment due to a non-standard front surface or fastening, then the pulleys must be unscrewed. It is necessary to stretch a thread or string between the flanges. Next, we apply a ruler to the flange and, if the elements are parallel, the two pulleys are on the same axis.

Tension problems, belt replacement

Car enthusiasts say that in 90% of cases, the cause of an uncharacteristic whistle 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 the technical passport of the vehicle.

Weak tension on the alternator belt reduces the efficiency of the alternator by an order of magnitude, causing it to not generate the required current. In addition, this is accompanied by rapid wear of the tape. On the other hand, too much tension increases the risk of bearing failure.

To tighten the generator belt, you need to unscrew the nut that connects the generator and the bracket. The bottom nut needs to be loosened a few turns. You can control and change the belt tension by slightly moving the generator away from the cylinder block. After all the manipulations, the nuts are tightened and a check is carried out - before starting the engine, several energy consumers are turned on (headlights or stove). If the work is done correctly, the whistle will disappear.

To replace the belt, you need to repeat the same steps, only you need to move the generating device until the belt is removed from the pulleys. After replacement, you need to let the engine run for a few minutes so that the belt fits correctly.

Specific problems for different brands of cars

Ford Focus 2

First, let's take the above-mentioned Ford Focus 2. On this car with 1.4 and 1.6 liter power units, the designers did not use a tensioner, considering that the attachment itself would do a good job of tensioning the belt. And this is true, but for now it is new and unworn.

During operation, the drive gradually stretches and this stretching on the Ford Focus 2 cannot be corrected in any way, since there is no tension roller.

Therefore, the whistling of the alternator belt on this car often appears due to insufficient tension of the element, and this problem can only be eliminated by replacing the product.

READ ON THE TOPIC: How to replace the Ford Focus 2 alternator belt.

On the same car, but with 1.8 and 2.0 liter engines, a tension roller is structurally provided, but on the restyled Focus 2 models there is a rather interesting technical solution - there is a roller, but it does not have a tension mechanism (instead there is a regular bracket, which the part is attached to the engine).

It turns out that there seems to be a roller, but it is useless, and when the belt is stretched, its tension will decrease and a whistle will appear. But this problem is completely solvable - pre-restyling models use a roller with a tension mechanism, which can be installed on the restyled version.

Otherwise, the reasons for whistling of the generator drive and working equipment on the Ford Focus 2 are the same as for other cars - dirt, ingress of technical fluids, wear of equipment bearings, etc.

Daewoo Lanos

For example, in Daewoo Lanos, the belt drives only the generator. That is, in most cases the drive element itself becomes the cause of the whistle.

But sometimes there is a problem such as a violation of the position of the pulleys or a slight misalignment of one of them (most often the generator, due to wear of the bearings).

And because of this, unpleasant sounds will be made under the hood. Therefore, if everything is in order with the generator belt, then you should pay attention to the pulleys.

Hyundai Tucson

Hyundai Tucson has its own specific problems, these include:

The surfaces of the belt and pulleys are not worn in (the sound appears after replacing the first element). The whistle disappears on its own as the products rub against each other);
Incorrect installation - the belt on this car is located along a complex path and covers many pulleys and rollers, so when replacing it is very easy to confuse the laying path and place the flexible element incorrectly;
Worn bearing of the additional guide roller (parasitic).

If we add standard problems to this, then establishing the cause of the whistle on the Hyundai Tucson is not so easy.

Lada Priora and Kalina

These car brands have different types of power plants.

At the same time, the configuration of the generator drive and attachments (if included in the package) is also different.

But in any version of the motor, in order to ensure proper tension of the drive, the design has a tension roller. And if the cause of the whistle does not lie in the belt, then the next element that should be checked is the tension roller.

Lada Priora has no specific reasons for the whistling of the generator drive, they are all common, but there are design features that are important to consider.

This car not only does not have an automatic belt tensioning mechanism, but also to adjust the tension you need a special key that turns the eccentric element, which is why the tension occurs.

Drive of auxiliary units on the Lada Priora car.

Check sequence on VAZ cars

If we take earlier versions of the VAZ, for example, 2114 or 2110, then their belt drives only the generator, so even the tensioner is not used (tensioning is done by displacing the generator itself). There are no specific reasons for whistling in these cars, they are all standard - incorrect tension, dirt, bearings, etc.

But on even earlier models - 2107 or 2108, the use of a V-belt alternator can be considered a feature. This type of drive is considered more reliable, but in terms of flexibility it is much inferior to a poly-wedge (multi-strand) drive, which is why it is not used on modern cars.

On these cars there is one specific reason for the appearance of a whistle - wear on the working surfaces of the pulleys. As a result, the belt sinks very deeply into the groove, which causes it to jam, accompanied by a squeal.

Moreover, replacing the flexible element solves the problem for a short time (until it wears in). To completely eliminate the cause of the whistle, you need to change the pulleys.

How to more accurately determine what caused the squeal, let's look at the examples of different cars.

To begin with, let's take a VAZ-2109 car. These cars were equipped with power plants with a single camshaft (that is, 8-valve).

What is described below is also suitable for other cars with this type of timing belt - VAZ-2110, VAZ-2114.

So, a whistle appeared under the hood, and to find its cause we proceed as follows:

We remove the alternator belt and start the engine to make sure that the sounds are coming from under the timing cover;
We dismantle the timing cover and assess the condition of the belt. It should not show signs of significant wear or traces of technical fluids. If one-sided wear is noted, there is definitely a misalignment in the rollers or pump, and you can immediately remove the drive element to check the remaining elements;
We evaluate the belt tension (in the area between the crankshaft and the timing gear, turn your fingers around the axis. A normally tensioned belt should not turn more than 90 degrees). If necessary, adjust the tension and check if the sound has disappeared;
We remove the belt and check the condition of the tension roller bearing and pump. There should be no play in these elements, and no jamming or wedging when turning.

By consistently checking all the elements that are involved in the timing drive, you can easily identify the cause of the sounds.

If significant wear is detected on the belt, tension element or water pump, they must be replaced. All these components cannot be repaired.

The above instructions are also suitable for the Lada Priora or Kalina, which are equipped with power units with two camshafts (16-valve versions), but there are some nuances:

In such engines it is much more difficult to remove the drive cover;
In a number of motors, the tension roller is equipped with an automatic tensioning mechanism. And it happens that it is this mechanism that jams, not providing proper belt tension;
In addition to the pump and tension roller, the parasitic roller should also be checked. Play in it is also not allowed, and severe wear of the bearing of this element is another reason for the appearance of noise.
In these cars, when replacing the belt, both rollers must be changed.

Everything described applies to other cars, for example, Renault Logan. This car is equipped with both 8-valve and 16-valve power plants, the timing drive of which is practically no different from those used on the VAZ.

Mitsubishi Lancer 9

The 9th generation Mitsubishi Lancer has another problem, the power steering pump, which operates from a belt and is located almost on the same level with the generator pulley, while there is no drive protection.

As a result of a not very successful design solution, dirt and moisture gets onto the working surface of the belt during operation, which causes slipping.

And it is almost impossible to solve such a problem, so short-term belt whistling in such a car is considered a “disease”.

Reno Logan

Reno Logan also has its own specific design features of the generator drive, which may cause a whistle to appear.

The first of them is the use of 6-groove pulleys, while the belt itself is 5-groove, and here when replacing it is very important to put it on correctly, otherwise the line of its position will be violated, in fact, a skew will appear, which is why a whistle will appear.

At the same time, with different numbers of attachments, the drive is installed in its own way.

On models equipped with power steering, the outer groove of the pulleys should remain unclaimed (the belt should be moved closer to the engine and components).

But in versions with power steering and air conditioning, on the contrary, the rivulets on the inside of the pulleys are not used.

The second feature is the absence of an automatic tensioning mechanism on models equipped with power steering. Therefore, on these Logans, when a whistle occurs, first of all, you should check the belt tension and, if necessary, tighten it.

Belt wear and other reasons

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

If you miss a scheduled replacement of the alternator belt, the risk of stalling in the middle of the road will increase every day. The belt may lose its elastic properties, crack or break. This process will be accelerated by poor quality tape.

To avoid problems with the drive belt and effectively eliminate the consequences of problems, it is better to find out more about the problem in advance. Visual videos will help with this:

Video “Whistling in the engine during cold start”

This video explains the cause of the whistling noise that occurs when starting a cold engine and how to eliminate it.

Almost everyone has heard a nasty squeak in the morning when starting the engine. The time for symphonies usually begins in the fall and continues until late spring. Meanwhile, you don’t have to look for the source of the frightening squeal for long - it is under the hood in the area where the attachments are located. It is often driven by a belt drive, the elements of which can produce extraneous sounds. The defect is not critical, but it is unacceptable to ignore it.