Hello, I'm troubleshooting a rotational thumping (for lack of a better term) noise when it's cold (around 32 degrees or less) and when I first start driving--fairly loud at first and definitely from the front of the car. After a mile or two, the thumping noise fades away until I no longer hear any thumping. When it's warm out, no thumping noise. The thumping frequency increases with speed and decreases when decelerating or coasting. I don't feel anything through the steering wheel. The tires are new. So, it's not a tire-related thing since thumping was there before the new tires. CV-Joints seem solid and boots are intact. I get no wheel movement when I perform the typical wheel bearing check by rocking the wheel at 12 & 6 and 3 & 9.

So, at this point, the only theory I can come up with is that the grease in the wheel bearing(s) is relatively solid when cold and unable to lubricate the failing(?) bearings in the hub. As the bearings warm up, the grease liquifies and is able to lubricate the bearings and the thumping goes away.

Appreciate any and all thoughts and theories since from a symptom standpoint that points to a fix, I'm kind of stumped.

Ron

 

You don’t state the year and mileage. Guess it’s a SS because that’s the forum you posted in ?
Have the front hubs ever been replaced ? If not, that would be my guess.

 

2009 SS. 84,000 miles. Original hubs.

 

I have had a bunch of wheel hubs go bad on my HHRs.

However, they always created a noise that sounded like a grinding noise that got louder the faster you drove.

I never had a thump, and the noise never went away just got worse over time.

If you hadn't mentioned that you put on new tires and the noise was there with the old tires, I would have guessed a tire was flat-spotting until it warmed up. But your statement seems to negate that cause.

I would suspect the axle shaft with its CV joints, but I can't think of a scenario where the noise would go away. Check the axle shaft nut at the wheel to see if its loose, admittedly this is is a long shot.

Steve

 

You say it's definitely from the front, but the hubs don't move and you don't feel the thumps through the steering wheel. You may want to entertain the possibility that it's the rear.

The thumping increases with vehicle speed, not engine RPM, is that correct?

 

There is not enough grease in the hubs to do that. And, they are ball bearings.

 

Maybe somebody put playing cards in the spokes.

 

Yes. Thumping increases and decreases with vehicle speed, not engine RPM. I will check the rear hubs tomorrow to be sure. That is a possibility since I have encountered times in the past on other cars when noises propagate opposite of where I think the noises are coming from until I have someone ride with me to help.

 

How about a right rear caliper not sliding/floating like it should and rubbing ****eyed on a slightly warped rotor causing my periodic "thumping" sound because of the slots and holes grabbing the inside pad. When I spun the wheel by hand, there was a pretty aggressive rotational, not constant, noise. I could see that noise might propagate through the car and maybe settle after a few stops. Thus why the sound would go away after a mile or so. Hub seems OK.

Thoughts?


Rear Rotor

Caliper 1

Caliper 2

 

Looks like paint has been rubbed off the caliper? Is the caliper contacting the disc?