In most cases, there is one reason for the appearance of a whistle, squeak, squeak or squeal from under the hood of a car - the alternator belt or timing belt is whistling. On modern cars, in addition to the generator, the drive belt can also rotate the pulleys of the power steering, air conditioning compressor, engine cooling pump and other attachments.
The reasons for whistling may vary. For example, a whistling alternator belt in wet weather can be caused by moisture getting on the belt and pulleys. And if the generator belt whistles when cold, this may be due to thickened lubricant in the generator bearings or tension rollers.
In this article we will talk about why the alternator belt whistles, what to do in such cases, and how to eliminate the drive belt whistle yourself.
The whistling may appear for a while and then disappear (for example, the whistling of the alternator belt when the engine is cold, during rain or when the air conditioner is turned on), or it may be constant. What to do and where to start looking for the cause of the whistle?
Types of hanging belts
Previously, cars were equipped with only one belt; it drove only the generator. In the process of improving engines, the number of power units that need to be driven, for example, the steering wheel and the compressor, increased. Collectively this is called attachments
. In the 21st century, it will no longer surprise anyone that the attachment consists of at least 3 units!
To transfer mechanical energy from the engine to the generator, cars use V-belts and poly-V-belts, the latter being more popular. Let's look at each type and look at their appearance.
V-belt
A belt having a trapezoidal cross-section and resembling a wedge shape, pointed on one side and widening on the other side. This type of belt ensures more efficient operation of the mechanisms and makes the transmission more compact.
V-ribbed belt
The belt, which has longitudinal stripes on the inside resembling wedges, got its name from the Greek “poly” - which means many. This type of belt is very flexible and has excellent traction capacity.
First sign
The belt may whistle when starting the engine, while driving, in winter, in rainy weather, etc. The duration of the unpleasant sound can vary from a few seconds to constant as long as the power plant is running.
As we mentioned above, in many cars, the alternator belt additionally ensures the operation of a number of equipment - power steering, air conditioning compressor, which increases the load on the drive and, as a result, the likelihood of a problem becoming higher.
And although many attribute the whistle to the belt drive itself, it may also indicate other malfunctions.
Belt drive features
Belting
- This is the transmission of mechanical energy using a drive belt.
This design has strengths
including a long service life, accessibility to maintenance and quiet operation. The belt is very strong and flexible, this allows it to be placed between many elements of attachments and set in motion.
Alternator belt using the example of a Lada Priora with air conditioning: 1) drive;
2) tension roller; 3) engine support bracket; 4) generator; 5) air conditioning compressor. However, there are also weaknesses!
The drive is demanding for the correct arrangement of elements, sensitivity to aggressive influences and the quality of the pulley surface.
As they wear out or become damaged, the moving parts experience additional difficulties during rotation, primarily affecting the transmitting torque. Whistling occurs
when the opposing force is too great.
Some tips for increasing the life of your alternator belt
Before and after parking the car for a long time, especially in the warm season, you can slightly “soften” the working area of the belt by lubricating it with a special product or a gasoline-water solution in a 1:2 ratio.
This will prevent the belt from cracking and protect it during routine maintenance. At the same time, make sure that there are no electrical wiring, clamps or rags near the belt.
After driving for a long time on a dusty road, use a compressor to blow through the rotation area of the alternator belt. Check the degree of tension at the beginning of each season, especially in severe frosts.
Remember that too much tension can lead to belt stretching and premature failure.
Why does the whistle appear?
In 90% of cases, belt friction is to blame.
at the moment of slipping. When the belt cannot transfer mechanical energy to the generator pulley, it simply slips, making an unpleasant squeal.
Most motorists make a grave mistake! Remember, you need to look not for the reasons for the unpleasant sound, but for the reasons causing the belt to slip!
Let's list the 5 main causes of slippage in chronological order :
- penetration of moisture, dirt and technical fluids into the mechanism;
- severe wear of the drive belt;
- drive belt of poor quality;
- weak or excessive belt tension;
- misalignment - parallel and angular misalignment are distinguished;
Consequences that may arise
An unpleasant sound cannot be ignored; it is a malfunction that can lead to even bigger problems.
- the intensity of belt wear increases;
- wear of mounted bearings increases;
- the belt can break at the most unexpected moment;
- The cooling system pump may fail.
If you ignore this problem, you will not be able to predict when the belt resource will reach critical, and this can lead to much bigger troubles.
Common causes of unpleasant sound
Below we will look at the common reasons
occurrence of an unpleasant sound.
We will not consider specific reasons;
they are specific to specific car models.
General
- depends on external factors and typical faults.
Resource exhausted
Nothing lasts forever, including a belt reinforced with strong threads. Belt drive transmits enormous energy and handles variable loads. Over time, the belt stretches, its surface wears out, the rubber delaminates, and it is negatively affected by environmental factors. The average resource varies from 40,000 to 60,000 kilometers, but much depends on the conditions in which the car is operated.
Dirty surface
Drive surface cleanliness is one of the most important factors affecting belt service life. If the drive is corroded, dust or dirt gets into it, all this acts as a kind of abrasive that reduces adhesion properties and service life.
The most harmful effects are caused by technical, caustic liquids. Rubber is very sensitive to them. The process of aging and destruction accelerates, in addition to this, the friction force decreases, which is why the alternator belt can slip and make an unpleasant sound.
Mounting location
A minimal deviation from the correct position of the pulleys relative to each other will have a detrimental effect on the belt contact patch. Deviations are: vertical-angular, horizontal-angular, parallel. In such a situation, the alternator belt will slip and make a whistling sound.
Please note that if any pulley rotates in a figure eight, it will tear and throw off the generator belt. Most often, pulleys with a rubber damper behave this way, which over time loses elasticity and ceases to perform its functions.
An indirect sign of pulley misalignment is the poly V-belt jumping from track to track and sliding off the pulley.
Belt tension
If the alternator belt is not tightened tightly enough, it will sag and slip. If it is overtightened, there will be a loss of adhesion, because the torque will prevail over the friction force.
On most machines, the tension of the alternator belt can be adjusted by loosening the nut securing the alternator housing to the adjusting bar and using a pry bar to move it away from the engine.
To check the tension, you need to press on the generator belt: it should bend by about 10–15 mm.
In most cases, the cause of a whistle from under the hood is precisely the weak tension of the alternator belt.
Bearing condition
Bearings perform the following roles:
- prevention of axial displacements;
- alignment of moving parts;
- reduction of friction.
If the bearing is faulty the following will occur:
- distortions and protrusions of pulleys;
- wedging;
- make an unpleasant “squeal.”
Condition of pulleys and shafts
During operation, pulleys, shafts, and rotors wear out; this occurs less intensely compared to bearings. Traces of mining have the greatest impact on the adhesion properties of the surface.
The wear appears at the points of contact with the bearings, causing play that cannot always be eliminated even by completely replacing the supporting elements.
Huge pressure
If the belt has insufficient tension, the whistle may be caused by the simultaneous switching on of energy consumers such as headlights, heated or ventilated seats, radio, or air conditioning compressor. Together, they place a heavy load on the generator, which is operating at the limit of its capabilities.
In the cold
Belt whistling on a cold engine is caused by excessive belt tension or thickened low-quality lubricant. Both reasons create additional resistance to shaft rotation; as the engine warms up, the problem disappears.
Rain and slush
Moisture on the surfaces of the pulleys does not create any negative consequences for transmission, this is considered normal! However, if there is not enough adhesion properties to transfer mechanical energy, the water that gets into the mechanism plays the role of a lubricant, causing the generator drive belt to slip. If you hear a whistling sound, the work surface is most likely worn out!
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.
Ways to fix the problem
To eliminate unpleasant sound, first of all you need to do the following:
:
- visual inspection and checking the integrity of the belt - today even new products can be of poor quality;
- checking the correct belt tension - most often due to weak tension, belt squeaks often occur;
- cleaning the work surface from dirt is another of the most common reasons;
- visual inspection of the pulley for damage;
- the line of two pulleys is checked for displacement;
- cleaning the pulley from dirt and rust;
- checking the condition of the mounted bearings.
You can follow part of the recommendation yourself.
. To check bearings and pulley deflections, you can contact a service station. In most cases, these measures are quite sufficient to prevent whistling.
If no faults are found
, the alternator belt continues to whistle, try to restore the elasticity of the product.
It is unacceptable to use petroleum-based fluids for lubrication!
You can use special tools
, which increase the elasticity of the belt, clean working surfaces and protect against moisture. There are many spray products on the market, such as Liqui Moly Keilriemen-Spray, Hi-Gear Belt Dressing or Verylub.
On a note! If the whistle disappears after using special tools, the alternator belt is most likely to blame.
Conclusion
The causes of whistling in the engine are considered. This effect is usually caused by worn parts. To eliminate the problem, you need to replace one of the elements: belt, tensioner, pump or generator parts. Not all car enthusiasts are able to do the process themselves, so it is recommended to contact a car service center.
An experienced driver can determine the cause of the malfunction and how to eliminate it by the sounds of his car. If the belt whistles when you turn on the air conditioner, then most often the problem is related to the V-belt drive. The article discusses the causes of whistling and methods for eliminating it.
