Serious problems with your car can be avoided if you recognize the first signs of malfunctioning in time and eliminate them immediately. Most often, violations in the operation of mechanisms are manifested by uncharacteristic sounds. Many drivers may not pay attention to them and miss the moment, when the problem could be solved by a small repair. What malfunctions of the car can be determined by hearing – let’s understand.
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Peculiarities of diagnostics by ear
More or less experienced drivers know that many malfunctions give themselves away by uncharacteristic sounds, which emit mechanisms.
Some of them can be picked up when the car is stopped – so malfunctions in the engine and attachments are manifested. Others occur during driving, and it is easy to distinguish them through the opened window. But for this purpose it is necessary to drive on a highway with moderate traffic at low speed – less than 100 km/h. Otherwise you will not hear anything because of the noise of the wheels, wind and passing cars.
The ideal place for such sound diagnostics is a quiet street with minimal traffic. It is better to drive along parked cars, a high stone fence or a curb – the sound will intensify and it will be easier for you to identify it. Moreover, it is necessary to drive along such reflective “screens” with open windows. And it is better several times: firstly to one side, then to the other. The speed should not be high. The optimal variant is 30-50 km/h.
During the diagnosis it is important not only to determine the nature of the sound, but also understand where it comes from.
Most of the car problems that can be detected by hearing are related to the engine, running gear, gearbox and steering system. A significant portion of these are caused by gaps in the mating areas that result in a knocking noise. Usually it becomes especially audible with the engine revs. Although in some cases the sound can become quieter – it all depends on the temperature of the unit and the quality of the lubrication.
The knocking becomes clear and audible as the clearances in the joints of the pistons, crankshaft, camshaft and cylinder block increase. It is most often characterized by an even beat, the frequency of which coincides with the crankshaft.
If the knocking becomes louder while driving, there is most likely damage to the crankshaft bearings. If the frequency of the knock is less, it indicates faults in other parts of the camshaft.
Muffled and loud knocks
Most often they appear due to damage in the crank mechanism. In addition, in cars with automatic transmission, such sounds may occur in case of cracking of the drive disc. 3.
One of the most difficult noises to recognize is wheel rumble, the intensity of which depends on speed. Such sounds may be caused by worn tread or hub bearings.
The most difficult thing for the driver is to distinguish, through the noise in the street, which wheel is making the humming sound. Usually it is not possible to do it at the first attempt. To do it, one has to swap wheels and listen to what has changed. Another option is to jack up the car and rotate the wheels one by one to see which hub bearing makes the humming noise.
This noise is often caused by a pad that has moved away from the brake disc. In this case, the brake caliper cylinders should be checked. Frequent rustling noises are a sign that the hub bearing has started to malfunction. If nothing is done, the damage will grow and the part will start making a humming sound.
Another reason for the rustling may be a malfunction in the caliper itself. Probably, its cylinders are stuck and therefore prevent the pad from moving away from the disc properly. In this case, there is accelerated wear on the disc. It overheats itself and at the same time warms the hub bearing. If you do not take action in time, you will need to replace the mechanism very soon.
Having heard such sounds, pay attention, whether they intensify with increase of revolutions. If yes, then check the oil level. For sure it will be below the norm. In this case the rhythmic tapping can be explained by improper valve adjustment.
While driving, the air currents create a natural noise, which increases as the speed increases. As a rule, it is not heard in the cabin due to the noise insulation.
If it does occur, the first thing to do is to check the door and window seals. It is quite probable that they are covered with a layer of dust and dirt. Because of this, they have ceased to fit tightly to openings, and street sounds started to penetrate into the appeared gaps.
Extraneous noise in the cabin may appear after the installation of a trunk or other additional devices (spotlights, spoilers, window deflectors, etc.). A lot of noise at high speed is also due to the disturbed geometry of the body after a bad repair.
Banging or squealing and whistling
While diagnosing, crank the engine so that it gives more than 3000 rpm, and push the gas pedal sharply. Repeat this several times. If there is a clanging sound, the source is a severely worn timing chain drive. If the vehicle has a belt timing, there may be a squealing or whistling sound. These are usually made by worn tensioner rollers.
If it appeared when trying to start the engine, it indicates a malfunction in the starter. The reasons for the malfunction may be different. But most often such a sound indicates a broken pinion.
Noises when starting the engine
If you hear a grinding noise when turning the ignition key, and it disappears immediately after the engine has grabbed and started running, it indicates a malfunction of the starter motor. You need to check the condition of the intake relay, bendix and flywheel. Most likely, the bendix pinion is not correctly meshing with the flywheel, so the process is accompanied by a grinding or crackling.
The alternator belt or the pump may make a whistling sound when starting the engine. This sound often occurs during hot starting – when the gas pedal is sharply depressed and the crankshaft speed is increased.
Sounds in the underhood space
If you hear a loud rattle, it is most likely caused by a worn bearing. Therefore, a more thorough diagnostics is needed. The booster pump, air conditioner compressor or other assembly may rattle. Ignoring such a sign is highly undesirable, because the malfunction may lead to the need for expensive repairs.