I have a 2016 Honda Accord Sport I4. I absolutely love this car, but have developed this major annoyance in the front left side. It's a mechanical sound, (grinding?) that increases in both volume and speed with every rotation of the front left wheel. It's been ongoing for 18k miles, with a total of 29k on the odo. Thus far, it's completely perplexed the Honda garage, and they've turned rotors, replaced pads, now on 3rd set of new rotors and pads, checked wheel bearings, brake backing plates, tires for unusual wear or bad belts... Anyone seen or heard something similar to this? Here's the video I put out on YouTube.

Thanks in advance for any advice.

Front wheel drive?

Have they checked the cv axle? If the sound amplifies with speed and they've rotated the tire and still hear the noise, then I'd say it's coming from the axle or the transmission.

May be a problem with the wheel. Check for runout. Of course if you have rotated the tires/wheels and it's always that left front, never mind. Look for witness marks on backing plates, and all around.

Do you feel a pulsation, or bump every time the wheel rotates (first order vibration). Sometimessage the tire and wheel can Mike out as being in spec, but vertical flex in the sidewall will do it. But then again, changing tires on that corner will reveal that issue right away. Is that an aluminum wheel, or a hubcap (with pebbles in it)?

Also, good advice above-mentioned, cv joint, speed sensor, axle, boot, transmission, etc.

quote:

Originally posted by Shaql:
Front wheel drive?

Have they checked the cv axle? If the sound amplifies with speed and they've rotated the tire and still hear the noise, then I'd say it's coming from the axle or the transmission.

Yes, FWD. They "claim" it's not from the trans since it's CVT but I'll ask them about the drive axles.

I won't be able to listen until later. Apparently the dealer confirms the noise is excessive and not normal. Is the noise increasing/decreasing only with road speed? Or does it change if you apply or release the throttle at the same road speed? Does it change if you steer the car rapidly from side to side? But, given all the low-hanging fruit that has been checked or replaced already, it might be time to look into the differential (integrated with the transmission) carrier bearings.

I have not used one myself, but this would be a good use for a "chassis ear" device, where you rig the suspected noise source(s) with microphones, drive the car and see which is the loudest.

Does the noise exist while on the hoist?

quote:

Originally posted by egregore:
I won't be able to listen until later. Apparently the dealer confirms the noise is excessive and not normal. Is the noise increasing/decreasing only with road speed? Or does it change if you apply or release the throttle at the same road speed? Does it change if you steer the car rapidly from side to side? But, given all the low-hanging fruit that has been checked or replaced already, it might be time to look into the differential (integrated with the transmission) carrier bearings.

I have not used one myself, but this would be a good use for a "chassis ear" device, where you rig the suspected noise source(s) with microphones, drive the car and see which is the loudest.

Chassis ear: Yielded nothing.

On hoist: they claim no noise

Off hoist: Persistent to ME, but 3 of the 5 techs they have cannot lay ears to it.

Road speed & throttle: It increases with throttle, mostly in speed of rotational noise, not amplification.

Directional changes: does not affect the noise

The Dealer is still not convinced there's a noise, however they've now had it 9 days and 3 others have confirmed it. I hear it all day everyday.

Very rare even on a high mileage car let alone this new one, but the support bearing for the longer drive shaft, on an intermediate shaft, is a potential source of noise. A fairly typical setup:


(The bottom one is the intermediate shaft; the support bearing is in the three-holed bracket.)

How are they running the car on the lift? At all? Unless there is a switch to turn it off, the traction/stability control is going to kick in as soon as the wheels start to spin and prevent the wheels from rotating fast enough, or even the throttle from working. And, is an identical car available to take for a quick spin and see if it also makes that noise?

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On hoist: they claim no noise

Really? ok. Not conclusive but interesting. Check the auxiliary parts on your engine (bad bearings on an alternator as an example. bad bearings on a pulley... I don't know what else is driven off of that belt in your car but check all that anyway) and it might be worth checking the belt for ware as well.

They say it's not a wheel bearing or anything related to the brakes. Ok.

You don't say explicitly but I assume they've swapped wheels around right so a different wheel/tire combo has been on the LF side?

I'd still inspect the cv axle.

Have them drain/flush the transmission. Noisy cvt transmissions are not unheard of. They require more maintenance than a standard sealed tranny.

You don't mention if the car drives differently, wanders, or alignment/steering concerns. Check the suspension for wheel play, look for bad bushings, suspension play or loose mounts.

Maybe get a set of used wheels and a set of new but not expensive tires and swap them out with current front wheels and tires?

Could it be those all along?

Try another dealership.. I'm not surprised that it doesn't make the noise when on the lift. The wheels would be hanging and not under load which could alleviate the problem. That would also help point the tech in the right direction.

I just spoke to the service manager, and they've since swapped wheels/tires off of a CPO 2017 sport (same 19" wheels/tires) and the noise was still there. I asked them to check the CV axles and he said they will do so. The next closest Honda store is 40 miles away but I may just have to do that. With each appointment I've had the original wheels and tires have been rotated, so I am still lost on this one. The noise itself, at least to me standing outside walking along with the car while my wife drives is isolated to the left front wheel / driveline area. The car drives straight as on arrow on good pavement without vibration or shudder. It does, however pull sharply when braking on uneven pavement (we have a lot of asphalt roads that cup).

I'd be looking at the CV joints in the axle based on the things you've ruled out already. They seem to have been trying the shotgun approach, after reading what all they've replaced. There are several things there that I wouldn't have thought likely to be the problem.
Have you called Honda? This car isn't that old and should still be under some sort of factory warranty.
Most brands have a area or zone service rep that visits dealerships to help with problems like that.

I'm now able to watch and listen to the video. I'm a little perplexed myself. It isn't the typical rumble/growl of a bearing, more like something dragging or rubbing. And it isn't very loud. I might think brake pads skimming the rotor, or the stone shield (aka but incorrectly backing plate) bent against the rotor, but this has supposedly been [finger quotes]eliminated.[/finger quotes] Is it really something you can hear from inside, even with the windows up and the radio off?

quote:

Originally posted by egregore:
I'm now able to watch and listen to the video. I'm a little perplexed myself. It isn't the typical rumble/growl of a bearing, more like something dragging or rubbing. And it isn't very loud. I might think brake pads skimming the rotor, or the stone shield (aka but incorrectly backing plate) bent against the rotor, but this has supposedly been [finger quotes]eliminated.[/finger quotes] Is it really something you can hear from inside, even with the windows up and the radio off?

Faintly, but yes I can hear it. I, too thought it was the pads skiffing the rotor but they claim not. I plan to call Honda directly as it is still under warranty. I'm going to pick it up now. They say there's nothing they can find....

As mention above, get the Honda zone factory rep involved. If the dealer is stumped then no problem it just needs to be nicely escalated up the ladder.

Good luck to you and please post back what it was.

a stone between the brake rotor shield and rotor somewhere?

I would ask to see the brake rotors from each side of the car. Because if you don't have a caliper releasing completely it will generate noise, heat, and polish the rotor more where the pad is dragging. Actually if you know someone with an infared thermometer you can drive the car for 1/2 hour to an hour and check the temp at each rotor. If you see more than a 20 degree difference there is the most likely cause for your noise.

PS; poor caliper retraction isn't always due to a bad caliper, quite often it can be caused by a kinked brake line or bad master cylinder.

I used to be the mid-lux service contact-rep for GM (C,H,E,K,G cars for Pontiac, Olds, Buick, and Cad). In extreme cases lIke this where the dealership is baffled, I used to have field engineeers that can visit the dealer and evaluate. They would often confer with me and the actual design or release engineer on a solution. I also would send the actual component engineer to the site to see what's up. See if Honda will do that for you. Or you can start a case for a buy back. That will get their attention.

Some Honda (and other) brakes (can't speak to this year/model) have V-shaped springs, two per caliper, that go into the brake pads and help keep them spread apart away from the rotor. If they are supposed to be there but got left out (they are a pain to keep together while you slip the caliper over them), they could be a potential noise source.