2013 Fit would make very noticeable hum when driving 35-45 mph and 65-70 mph. That started few years ago, was hardly noticeable at first and seemed to go away completely on occasion, for example after changing wheels (regular <-> snow). Gradually, the noise became stronger and stronger. At that point, changing wheels to another set did not change the humming noise at all. Two mechanics blamed the noise on driver side front wheel bearing although one of them was a bit surprised to determine that the humming noise would not be affected by left/right turns (he explained that turns are unloading left/right wheels respectively and that's expected to change the humming noise, which makes sense to me). The bearing wasn't in a must-replace-immediately shape as there was no play and no noise/resistance/grind when rotated by hand, but I decided to go ahead with the repair.

After replacing the wheel bearing the humming noise disappeared, but came back exactly the same after less than a thousand miles. It is the same speed intervals and even the same change in intensity of sound when I move my head from normal driving position toward the passenger seat. How likely is that, by a freakish coincidence, the replaced wheel bearing become defective in exactly the same way as the original one? Doesn't seem very plausible. Is it possible that the sound wasn't even caused by the wheel bearing in the first place, but by something else in the vicinity that was temporarily "fixed" or moved by the repairs, but eventually settled back to the same position? As I understand mechanic had to move quite a few parts during repair, including axle that goes into transmission. Is it possible that the hum comes from transmission bearing (sounds like a worst case scenario) or conversely from something benign like a suspension spring vibrating? How could I possible diagnose the actual source of this humming noise? Any advice is greatly appreciated.

 

I really don't know or have any idea of what it might be on your Fit.
I do know that when I've had wheel bearings go out....they never make a humming noise. More of a scraping noise in time with the wheel revolutions.

 

Don't know about anyone else, but I get significant amount of wind noise if my hubcaps (wheel covers, whatever) are not installed just right. Seriously. Have you driven your car without any hubcaps on?

 

Was the rim changed with the change of tires? You might try swapping the front tires to see if the problem moves to the passenger side. Best of luck, Clay

 

Yes the rims were changed going between regular and snow tire. Both are complete set of wheels, I just swap them when seasons call for the change. So the sound I am hearing is definitely unrelated to tires/rims.
Oh and I did drive the car without hubcaps (it is impossible not to do that when I have snow tires on - the regular hubcaps don't fit the rims used on those wheels).

On related note, is there a way to rotate wheels at 35 mph while on jackstands? The rear wheels I can rotate even by hands (although maybe not quite 35mph , there is hardly any resistance, but for the front ones transmission appears to be making quite a bit of resistance even in neutral. And if I turn the motor on and put it in drive and apply gas, the traction warning light comes on and wheels rotate quite slowly.

 

You've already got some good advice! :}
I don't have any tricks for getting the wheels to spin fast while on stands if they don't want to. Have you looked for grease/goop on CV shafts? Each of those also has two bearings and I think they could hum if their grease escaped.

Hearing the word "hum," my immediate thought is tires. I know that as they wear down the air that enters the tread while driving gets forced through tighter channels which can intensify sound. Some tread designs can hum or howl brand new, but you said changing the tires didn't make a difference.. Are you also certain the speed at which the noise occurs is as you stated above, consistently?

I'd like to add that, having just done wheel bearings on a different car, it's possible to screw them up by installing them crooked or compressing their side covers.. But that wouldn't explain an identical fault or the time preceding recurrence of the noise.

The very specific speeds at which the noise occurs makes it sound like the problem is wind or harmonic stuff (like little vibrations that built into noticable noise when other stuffs vibrating at the same speed). I've dealt with specific speed noises with an exhaust system on a different car.. Droning in drive only, around 40 mph (more accurately, near 3k rpms right before gear changes, but the 2nd to 3rd change was most likely to bring it out.) The automatic transmission limited the time spent at the specific RMP that caused the resonance issue, so it made an rpm under load thing seem like it might be a speed thing.

Another speed specific noise I'm aware of was result of a bad windshield seal. It was restricted to higher speeds where air would get channeled just right through or over a gap in sealant.

..My best guess for the fault going away temporarily is that a brand new wheel bearing is super smooth and needs time to break-in. Maybe once it broke in enough, the harmonic situation recurred? I don't really have a direction to point you in.. but maybe something here will spark an idea? I suppose even a vibrating heat shield could hum

 

Thanks, Pyts. It is an interesting idea that not-super-smooth bearing might be producing normal vibration that causes some other part to resonate and hum. It seem a bit convoluted, but fits what I observe. Not sure how to check that though. It really sucks that there is no simple way to disconnect a wheel from the transmission. As I understand it takes minimum of separating lower arm ball joint, removing spindle nut and pulling knuckle away. Would it be tricky for someone who has never did that? Looks reasonably straightforward on youtube.

What worries me the most I guess isn't the wheel bearing, but a possibility that hum is coming from transmission, more specifically, the differential. About forty years ago I was in car that made some humming noise for a while and eventually it got both rear wheels completely locked at 50mph. It was a rear drive, the differential leaked and eventually seized up completely. That very scary experience; fortunately there were no cars on the highway, but the car ended across the two lanes. Front wheel drive would have made it even worse I think, but hopefully Honda makes car that do not fail so catastrophically.

 

Does a front wheel drive car have a differential? Problem with a drive axle perhaps? If it's on one side better to go from the wheel toward the transmission to check for function, Pull the drive axle out and examine it. It has bearings in it so they could vibrate. That soulds like a big job but not really. Hopefully not a transmisson problem. There is a heavy metal connection between the axle, the transmission and the drive wheel. Best of luck. Clay

 

"With front-wheel-drive (FWD), the differential is alongside the transmission inside a housing, and the unit is called a transaxle. With rear-wheel-drive (RWD), the differential is between the rear wheels, connected to the transmission by a driveshaft."

If your transmission fluid is full/good, your diff fluid is full/good.
The convoluted stuff is always the most fun.
Wheel bearings should gradually increase in volume as the rotation of the associated wheel increases. I can't imagine why it'd come and go at set speeds, though that doesn't make it impossible! What does sound impossible, no pokes or jabs intended, is that a new wheel bearing would produce the same exact symptoms as the one it replaced.
I'd check around for loose stuff.
Before the wheel bearing replacement, what was the last service done on the car?

Also, here's a fun thread from a ford flex forum where some gents had dealerships diagnose speed specific hums under assumption of a bad strut.
If you can, post up the RPMs at which the fault occurs. If it's unrelated to rpms, we could rule out some stuff

I'm also super ready to eat my many words IF the time comes

 

>What does sound impossible, no pokes or jabs intended, is that a new wheel bearing would produce the same exact symptoms as the one it replaced.
I completely agree.

>Before the wheel bearing replacement, what was the last service done on the car?
There weren't anything much done, only scheduled fluid changes. The Fit is 2013 and the only repair it required so far was replacing one of the ignition coils destroyed by loosened spark plug long before the humming noise started to bother me.

>If you can, post up the RPMs at which the fault occurs. If it's unrelated to rpms, we could rule out some stuff
It is definitely unrelated to rpms. To establish that I used straight road with slight incline, increased speed 30->40mph (rpms 2000-2500), observed humming appear above 35 mph, shifted to neutral and coasted with rpms slightly above 1000, which did not change humming in the slightest; lighly touched brakes to smootly decrease speed, humming noise disappeared only after speed decreased below 35mph.

 

Get one of those automotive stethescopes to listen when rotating the wheel. The sounds that you may hear are suprising. I had a pulley wheel I was wondering about and it sounded fine untill I used the stethescope and it sounded like li was full of marbles in a steel can! Not hard to diagnose with the right tools. Auto stethscopes come with an ear and a steel rod with a diaphram attached. The rod is best for internal bearing noises. Best of luck Clay

 

A stethoscope would be a good call for verifying the bearing.

Throwing another curveball at yuh before I forget. Found this thread. The last post may be relevant, isn't vehicle specific, and isn't necessarily speed specific.

"I have a 2006 Mazda 3 that had the same problem right after I replaced the rear brake pads but retained the original rotors. After about a week, it developed a humming noise at low speeds, similar to the sound when you rub a wet finger on the rim of a wine glass. At times, it seemed like there were trumpets in back of the car and it can get quite annoying and embarrassing when going out of the parking area. The noise goes away though at speeds above 20 MPH.After a thorough inspection, I noticed that my rear rotors developed a slight lip at the inner and outer edges. The noise is caused when the edges of the inner brake pads hit the lips of the rotors. The replacement Bendix brand pads that I used had a clip system for the inner pads instead of having springs on top, as with my original Mazda brake pads. Unfortunately, the clips do not do a good job of holding the inner pads well in place thus after some running, the edges of the pads hit the lips of the rotors and the resulting noise."


TLDR: Do your rotors have lips?

 

I did not know there is such a think as automotive stethoscope, but it makes perfect sense to try. Will order shortly - Thanks!

Brake idea is an interesting one, but I don't see significant rotor lips nor did I change pads any separately from rotors. Besides if noise is produced by pads/rotors I would expect that applying breaks even slightly would change noise intensity/pitch, which isn't happening in my case.

Can anyone please comment on how easy/difficult it is to screw up the wheel bearing during replacing? As I understand it involves using a hydraulic press. If a bearing isn't perfectly sized for the hub or for the knuckle, pushing too hard to force it in its place might damage the bearing, right? I did buy bearing and hub from different sellers (and probably different manufacturers, not Honda OEMs either). Could they be mismatched if there is such a thing in this context? Mechanic that did the installation did not express any concern about that as I recall.

 

I replaced one of mine and used a NSK bearing. It's the brand used as OEM for Honda. Just in case your new bearing is funky you may need to order a good one to have a good bearing installed without going to Honda dealership. How much that would cost you can imagine. Best of luck Clay

 

nsk bearings are $30. A is $100 (may damage lug nuts). Actually, from looking at replacement hubs it looks like you could use two properly sized metric bolts to work the hub off like with the screw holes in some drum brakes. then you could take just the hub to a shop and I think it'd be cheap just to get the bearing separated and a new one pressed. $30-50?

take it home and install the hub


​​​​​That's as close as I get to shop labor. If you go that route, I'd recommend class 10.9 bolts with hex heads, maybe some anti-seize. Snapping a bolt off in the hub would really suck.


​​​​​​Edit: bearings can be screwed up pretty easily.. Not sure what fancy adapters guys in a nice shop would have, but if those side covers on the bearings get pressure, or smacked with a hammer, it's bad. if they get pressed in crooked, it's bad.. I think the LCAs are made of harder metal than the bearings, so it's just the bearings that get chewed up if driven crooked, not 100% on that though.

Even so, maybe it's something with your brakes or axels. We'd certainly know it's not the bearing if a third one doesn't eliminate the fault, yeah?