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Discussion Starter #1
I own a 2017 Bolt, which I’ve driven over 80,000 miles. So I’m pretty familiar with the car and its characteristics. I’m a long-time lurker here, since 2017.

In the last couple of weeks, my car has started making a sound that is fairly annoying. I’d like to bring it to a dealership to fix, but want to see if I walk in the door with something helpful.

The sound becomes audible at about 42 mph. It seems to keep the same tone, but gains intensity as speed increases. At 65-70 mph it seems to be most intense. At 80 it virtually disappears.

It almost sounds similar in tone to that of a small 4 cylinder engine.

It seems to emanate from the motor compartment. I almost think I can feel some vibration through the pedal.

But it doesn’t seem to be heard outside the car; when driving through a tunnel, it doesn’t seem to echo around me. It seems to emanate from the front of the car into the cabin.

It seems to increase/decrease with speed (much like tire noise might), but doesn’t increase/decrease in direct response to the pedal like the motor does.

L versus D makes no difference. HVAC on or off makes no difference. Applying regen paddle makes no difference. The car’s efficiency doesn’t seem affected.

It’s very strange. It seems to be some component of the drivetrain. Maybe - maybe - it could somehow be related to the regen system even though L/D and regen paddle makes no difference.

And it’s annoying - it’s an extra sound that doesn’t belong there.

Any thoughts? I know sounds are frustrating to diagnose (is it a “ker-thunk or a “clunk”), and if you’ve stuck with this post this far, I very much appreciate your patience.

Thanks!
 

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I would start with these thing to check:
Tires: Rotate fronts to rear and see if sound moves with them. Although sometimes it can be a wear issue on all four. Inspect tread for signs of unusual wear (google it).
Axles/CV Joints: Check boots for damage and look for grease splatter.
Wheel bearings: Harder to diagnose (again, google is your friend).
 

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I would definitely look into tires (uneven/irregular wear patterns can cause noise) and wheel bearings (does the sound change when changing lanes?)
 

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I would definitely look into tires (uneven/irregular wear patterns can cause noise) and wheel bearings (does the sound change when changing lanes?)
I realize trying to describe a sound is as hard as describing a smell, or a taste to someone. That said, is it a rumble, a buzzing, a scraping, a thumping, a rattling? High or low pitch? I was driving an older car of mine with many miles on it, and also knew all the usual sounds it normally made. Driving down the freeway there was all of a sudden a rumbling vibration that i could feel, and hear. I pulled over and checked axle, cv joints, (as best as can be done on the side of the road) Felt all over the tire treads, finally found a small bulge on the inside side walls of a front tire. It deformed the tire just enough to cause the vibration, and rumbling.
 

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Due to the sound varying with speed I would first check the push pin fasteners holding the plastic covers under the car and in the wheel wells maybe allowing the covers to flutter in the wind.
 

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Rotate the wheels, change pressure in them (on different occasions - front and then rear - you get the idea?).
Then, drop in N. Let it coast - can you hear it?
When the noise is there, drop in N again and apply the brake, increase the force.

finally, at some point, find a long curve, but tight enough to experience significant weight shift. Any difference left or right turn?
 
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Discussion Starter #8
I’ve rotated the tires, and dropped it into neutral while going 68 mph. Both great suggestions for an easy test. But no change in this strange noise.

I have an appointment at a Chevy dealer on Friday. We’ll see what they have to say.

Thanks for the suggestions!
 

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Discussion Starter #9
They confirmed the sound and recommend replacing the left front wheel bearing. It’s pricey - nearing $800. Searching on ”wheel bearing” on the forum led me to a 2019 thread by Voldar, in which he replaced the left front wheel bearing under what seem to be similar circumstances:


His was replaced under warranty - I‘m pushing 82,000 miles…

In any event, he said they did a great job, so it appears to have fixed his issues.

Another thread also talks about others having wheel bearing failures:


I should have the car back tomorrow and will report back.

Thanks to all, and especially @MisterJJ!
 
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