A foreign sound in the cabin or outside the car is always a signal that something is wrong with the technical condition of the vehicle. Ignoring primary-symptom It can lead to expensive repairs and, in the worst case, an emergency on the road. Noise in the car when driving can be caused by dozens of different factors: from a banal pebble in the tread of the tire to critical wear of the transmission elements.
The driver needs to learn to distinguish the nature of the sounds to roughly understand which direction to move when looking for a malfunction. A hum, a whistle, a bang, a rattle or a hiss – each of these sounds has its own originating nature. Modern cars They become increasingly quiet due to improved noise insulation, so any foreign sound becomes noticeable immediately after it appears.
In this article, we will discuss in detail the main sources of noise, methods of their self-diagnosis and ways to eliminate them. Understanding where the sound comes from will help you save time in the car service and possibly avoid wasting money on replacing the parts.
Noise from wheels and tires: diagnosis and causes
The most common cause of hums amplifying with a set of speeds is the condition of tires and wheels. Often drivers confuse this sound with the hum of hub bearings, but the nature of their origin is different. If the noise is uniform and varies depending on the quality of the road surface, then most likely the problem lies in the nature of the road surface. rubber-mix Or a tread pattern.
The so-called “noise” of rubber depends on the type of tread. Winter tires with aggressive pattern always hum stronger than summer counterparts. However, if the hum appears suddenly or becomes unnaturally strong, it is worth checking the wheels for uneven wear. Hernias, swelling. or "bald" spots on the tread create a beat and a characteristic low-frequency hum, which is transmitted to the body.
- 🔊 Uneven wear of the tread ("hernia" or steps) causes a rhythmic knock or hum, the frequency of which depends on the speed.
- 🔊 A stone or nail stuck in the tread makes a clinking sound, which is often confused with the knocking of valves or suspension.
- 🔊 Too high or low tire pressure changes the nature of road contact and can create whistling or humming sounds.
⚠️ NOTE: Operation of a vehicle with a damaged sidewall tire or a clear "hernia" is strictly prohibited. This can result in instantaneous rupture of the wheel at high speed and loss of control.
It is also important to consider the balancing of the wheels. If a hum or vibration appeared on the steering wheel after the tire fitting, it is possible that the loaders were installed incorrectly or lost during the movement. Imbalance causes not only noise, but also accelerated wear hub-bearing and suspension elements.
Hub bearings and suspension elements
One of the most dangerous and common problems is the failure of the hub bearing. The sound produced by a dying bearing is often described as an airplane hum or howl that builds up in proportion to the increase in the speed of the car. Unlike the noise of the tires, this sound is depends The quality of the road surface and can change when turning the steering wheel.
To diagnose malfunction, the method of changing the load on the axle is often used. When you turn the steering wheel in one direction, the weight of the car shifts, and if the bearing buzzes more strongly, the problem is in it. It is important to understand that ignoring this symptom will lead to a jamming of the node, which at high speed is fraught with wheel-off Or breaking a turning fist.
In addition to bearings, the source of noise can be Silentblocks, ball supports and steering tips. Worn-out rubber metal hinges begin to creak or crunch, especially in the cold season. Metal knocking during the passage of irregularities indicates the presence of backlashes in the joints.
| Noise source | Nature of sound | When it comes to | Danger. |
|---|---|---|---|
| Stack bearing | Monotonous hum, howling | Drive from 40 km/h and above | High (clining) |
| Silentblocks | Scream, thud knock. | On the roughness, on the turns | Medium (deterioration of controllability) |
| Ball-pillar | Dry metal thump | When passing pits at low speed | Critical (wheel break) |
| Shock absorbers | Knock, creak. | When the suspension is cut off and compressed | Medium (loss of road contact) |
☑️ Diagnostics of suspension with their own hands
Extraneous sounds of the engine and attachments
If the noise is coming from the engine compartment and changes depending on the engine speed, and not the speed of the car, then you should look for a problem in the power unit or its body kit. Often drivers are frightened when they hear a metal clang or whistle, but not all sounds have fatal consequences. For example, belt-whistle The drive usually indicates their slipping or wear, but does not require immediate stop if there is no smell of burning.
More serious sounds, such as metal knocking "cold" or "hot", may indicate problems with hydraulic compensators, a chain of HRM or crankshaft inserts. The thud of the GRM circuit often resembles the sound of a diesel engine even on a gasoline engine and requires the tensioner or the chain itself to be replaced. Hydrocompensators They may knock due to poor quality oil or clogging of lubrication channels.
The source of noise can also be the pump of the cooling system. When the bearing of the pump fails, a characteristic howl or hum appears, which can be intensified with an increase in the temperature of the engine. If the pump is not replaced in time, it can jam, which will lead to a break in the timing belt and, as a result, flexion.
Why is the generator belt whistled?
The whistle of a generator belt most often occurs due to the ingress of moisture, dirt or oil on its working surface. Also, the cause may be a weakening of tension or critical wear of rubber. In winter, a whistling on a warmed-up engine often indicates that the belt has “suffocated” and lost elasticity, requiring replacement. Don’t ignore the whistle, as a break in the belt will leave the car without charging the battery and cooling the engine.
Transmission noise: transmission and drives
The transmission of a car is a complex mechanism that transfers torque from the engine to the wheels. Any malfunctions in this system are accompanied by specific sounds. If you hear a crunch when you switch gears, it may indicate wear on syncs or clutch problems. On mechanical boxes, a hum is often found, which changes or disappears when the clutch pedal is squeezed.
In front-wheel drive cars, SRUS (shafts of equal angular speeds) become a frequent problem. “Grenades”, as they are called in the people, begin to crunch when turning. The internal SRUS usually crunches when accelerating in a straight line, and the external one - when the wheels are turned out. Ignoring this sound will lead to the complete destruction of the hinge and the impossibility of transferring the moment to the wheel.
- 🔧 The hum in the gearbox to neutral often indicates wear of the bearings of the gearbox shafts.
- 🔧 Vibration and hum of the driveshaft (on rear-wheel drive cars) speak of imbalance or wear of crosses.
- 🔧 The howling sound of the rear axle gearbox is usually associated with an incorrect gap in the main pair or a lack of oil.
It is important to monitor the level and condition of transmission oil. Old, lost its properties oil does not create a sufficient protective film, which leads to dry friction of metal parts and the appearance of noise. Regular replacement liquids in the transmission units can extend their resource at times.
⚠️ Warning: If you hear a sharp metal grinding in the transmission, stop driving immediately. Continuing the trip can result in expensive repairs or replacement of the entire unit.
Diagnostics of the transmission requires experience: the sound of the SRUS is easily confused with the sound of the suspension, so if in doubt it is better to contact professionals at the STO.
Aerodynamic noise and body problems
At high speeds, usually above 90-100 km/h, the main source of noise is air. Aerodynamic hum can occur due to improperly installed body kit elements, roof trunks or even open windows. If you notice that the car has become "noise" wind stronger than usual, examine the body for the subject. gap And the loose fit of the parts.
Often the source of whistles are door seals. Over time, the rubber dries, cracks or peels off, letting air flows into the cabin. This not only creates discomfort, but also increases the load on the ventilation system. Checking seals is a simple procedure that can be performed visually and to the touch.
It is also worth checking the fastenings of plastic elements: splashers, underflates, moldings. A loosened under-wing at high speed can create a strong noise and even rub against the wheel, which is dangerous for the destruction of the arch or tire. Vibration. Plastic body panels can also generate an unpleasant low-frequency hum.
A regular water hose can be used to check the tightness of the seals. Direct a stream of water to the joints of doors and windows while the assistant is inside the cabin. The appearance of drops will indicate the place of leakage and penetration of air.
Methods of self-location of sound
To effectively combat noise, you need to pinpoint its source. Professional diagnosticians use stethoscopes and special equipment, but in garage conditions you can conduct a qualitative check. The simplest method is to change the driving conditions. Try to change the speed, engine speed, turn on or off the gear, turn the steering wheel.
If the sound depends on the engine speed (checked at the parking lot), then the problem is in the engine or hinged. If the sound depends on the speed of rotation of the wheels - look in suspension, transmission or tires. It is also useful to drive on different types of coating: asphalt, primer, paving stones. Deaf knock on the pits will indicate the suspension, and a monotonous hum on smooth asphalt - on bearings or transm
For more accurate diagnosis, you can use a long screwdriver or a wooden bar. By applying the screwdriver handle to the ear, and the sting (carefully!) to the node being checked, you can localize the source of vibration. This method works like a stethoscope, amplifying the sound from a particular part. Be careful with the rotating parts!
Using a smartphone for diagnostics
Modern smartphones have sensitive microphones. Download the spectroanalyzer app or just turn on the recorder. Record the sound of the car in different modes. When listening in headphones, you can often hear details that were not noticeable in the noisy garage. You can also compare the sound recording of your car with the reference recordings of a serviceable car of the same model on car forums.
FAQ: Frequently Asked Questions about Car Noise
Why does the car only hum at a certain speed?
This phenomenon is called resonance. At a certain speed (speed) the vibration frequency of the engine, wheels or drive shaft coincides with the proper frequency of oscillations of the body elements or suspension. It can also indicate a specific malfunction of the bearing, which begins to "sing" at a certain speed.
Is it dangerous to drive when you hear a light hum?
Depends on the source. If the tires or aerodynamics are buzzing, it is safe but noisy. If the hub bearing or transmission is buzzing, it is dangerous. Operation with such malfunctions can lead to jamming of the node on the move, loss of control and accident. Better get a diagnosis.
Could the noise in the car be related to the exhaust system?
Yeah, definitely. The garment of the muffler, damage to corrugated corrugated or a loose connection of the exhaust system pipes create a loud bass hum or roar, which is enhanced when pressed on the gas. This is often confused with engine noise.
How to distinguish the noise of the bearing from the noise of the transmission?
The hub bearing buzzes constantly when moving and changes tone when turning the steering wheel. The noise of the gearbox often depends on the gear on and may change or disappear when the clutch is squeezed (on the manual transmission). Also, the hum of the gearbox is often accompanied by difficulties with switching speeds.