Odd Noise -- what do you think it is?

[Tystevens]

My '07 OB has started making a new, odd noise, after just one month of ownership. First noticed it yesterday driving to lunch.

It is a whiny noise that seems to increase and decrease in amplitude with wheel speed (as opposed to engine speed or transmission speed), so I'm kinda thinking something in the differential/axle/wheel area of the car, or possibly transfer case. Since it doesn't make the noise when stopped, I can't tell for sure, but it seems to be coming from the front of the car. At 25+ mph, it is high pitched squeak, while under 5 mph it is almost a low growl. No vibrations, grinding, etc. associated with it, even when in low growl mode -- doesn't seem like brakes or a wheel bearing. Doesn't increase or decrease when turning, so I'm thinking it isn't a differential.

Any thoughts?

[1 Lucky Texan]

could you have someone drive the car while you jog next to it to pin down left/right or center source for the noise? Doesn't seem like typical axle noises/problems. Seems more like a wheel bearing.

sounds like you know it isnt' the brake squealer so, maybe put the front on jacks and try moving the wheels around and feel the springs while rotating the tires to detect rough wheel bearings.

[jogosub]

Check the rubber belt - maybe it's slipping upon acceleration. With an older car that may be the case. On my son's Honda that was the case - when car was not moving there was no noise. You can either tighten the pulley tensioner, replace the belt or spray belt dressing on the belt (the cheapest immediate solution) - if that is the source of the noise.

[subiesailor]

Rock stuck in the brake shield is not uncommon - belts - brake squealer etc. You need to share more details or record it and post it on youtube and share

[Tystevens]

Thanks guys for the responses.

I'm not thinking its a belt, because the noise isn't tied to motor speed or load (eg, revving motor in N while moving doesn't change the noise, and revving at a stop doesn't make the noise occur). Also remains constant when I manually shift the transmission.

Also don't think it is brakes -- applying the brakes doesn't cause any change to the noise at all.

I don't know if the mic on my phone is sensitive enough to pick it up if I recorded it, but I can give than a shot.

If it is a wheel bearing, it is the oddest sounding wheel bearing I've heard before. Do the fronts tend to have problems? I thought it was just the rears on the 3rd gen.

I'll keep looking - I haven't had time to climb underneath, but I should be able to look more closely tonight.

Thanks again!

[beetles1900]

Originally Posted by Tystevens

Thanks guys for the responses.

I'm not thinking its a belt, because the noise isn't tied to motor speed or load (eg, revving motor in N while moving doesn't change the noise, and revving at a stop doesn't make the noise occur). Also remains constant when I manually shift the transmission.

Also don't think it is brakes -- applying the brakes doesn't cause any change to the noise at all.

I don't know if the mic on my phone is sensitive enough to pick it up if I recorded it, but I can give than a shot.

If it is a wheel bearing, it is the oddest sounding wheel bearing I've heard before. Do the fronts tend to have problems? I thought it was just the rears on the 3rd gen.

I'll keep looking - I haven't had time to climb underneath, but I should be able to look more closely tonight.

Thanks again!

My 05 had a bad front driver-side wheel bearing. Noise was very odd sounding, like no other wheel bearing anyone had ever heard. Sounds like the low growl of a jet airliner winding up for take off as you accelerate, all the way up to the high pitch as the plane gets airborn. My bearing was bad, wheel turned smooth and quiet on the rack, no wobble when you pulled on the wheel. The speed sensor finally failed and engaged the check engine light on mine and gave a code for bad speed sensor, and then they replaced the bearing becasue that finally convinced the mechanic the bearing was bad (after I begged for 2 months for a new bearing). Driving on the bad bearing took out my brake pads and I needed a brake job too. Check your brake pads, if you have excessive or uneven wear, the bearing(s) are bad and the rotors may have uneven wear too. If I was you, and I could afford to replace both bearings, I would consider it. Otherwise, the bearings are very hard to diagnose on these cars until they fail very badly, the bearings are that good, even when they are bad they still roll pretty straight until you put weight on them. The usual "spin the wheels on the rack" diagnosis techniques just don't work really good on these cars!!!
Good luck!!

[Tystevens]

Thanks for the input. That is probably a pretty good description of the noise, actually.

I did take it back to the dealership, as I received a 3 mo/3000 mile warranty on the car (I had forgotten that was offered). I was a 2950 miles on Friday, so I figured it better take it in or lose the chance. Unfortunately, it snowed/rained pretty heavy on Friday, and I couldn't get the car to duplicate the noise when I got to the dealer. They did put it up on a lift and inspected the bearings, brakes, etc. He said everything looked fine, although he did mention that the brakes appear to be wearing kinda funny. I don't think it is brakes, though, since the noise was the same whether brakes were applied or not, and every other brake issue I've ever had makes varying noises depending on application of brakes.

Drying out today, maybe the noise will be back or maybe not. Thanks again for all the input.