Did I get something wrong?There is a humming sound in the car while driving. It is very obvious when the speed is 50km/h, and it can also be heard at other speeds. It does not seem to be related to the accelerator. I took a video.
This is a used car. I don't know what the previous owner did. I have adjusted the toe and lubricated the brake caliper guide and piston. I suspect the sound comes from a bearing. I wonder if this sound is normal? The whining sound is actually more obvious than in the video
"IF" it's a wheel bearing, you'll have to pull the axels, and press the brake pads back so you can rotate the hub(s) and listen for grinding. Though you might be able to skip pressing the pads back. With the rears, you also may be able to spin them without removing the calipers.
If the whine has a pitch, and you can hear it at 30, 40, and 45 road speed, is the pitch do, fa, and sol, respectively, at those speeds? (This isn't a perfect-pitch question; it's the intervals that matter, not any absolute pitch.) If so, it could be a wheel bearing. If not, better look elsewhere.
There seems to be no change in pitch, no pitch change like do fa, only a change in volume. Sound volume is related to speed. It is most obvious at 53km/h. Above or below this speed, the noise will be attenuated. The noise has nothing to do with the throttle. When accelerating or decelerating at the same speed, the frequency of the noise will not change. I even suspected that the noise was caused by gear meshing in the gearbox. Paradoxically, neither RPM nor vehicle speed can affect the frequency of the noise. If it is wheel bearing noise, does its frequency change with vehicle speed?
Yes, the tires are worn. The first two have been used for about two years and have a mileage of about 20Kkm. The rear two have not even been replaced. I don’t know the mileage. The tread wear is close to the life indicator bar. Even if there is no eccentric wear, it has become It's very hard, maybe that's a problem with it。
I generally expect anything that is fixed to wheel speed (so, tires, wheel bearings, anything back to MG2) to have a pitch, if discernible, that varies directly with road speed, So if it doesn't, I start thinking of other things.
Rotate the tires and see if the noise moves. Otherwise it sounds like a wheel bearing to me. Usually you can hear if it’s front or back but the left or right guess is often wrong. The speed you are hearing it the loudest is typical, normally road noise at higher speeds drowns it out. Sometimes you won’t hear it for a couple of miles when driven the first thing in the morning after being parked overnight.
