Wheel Bearing Diagnosis - Am I on the right path?
 

I did a bad job of checking things out when I bought this 98 C5. When I took it for a test drive, I drove it with the top off and thought I was just hearing outside road noise. I took it in to a mechanic for inspection before buying it, but I guess they didn't drive it.

I think I have a bad rear passenger wheel bearing. Here are the symptoms and diagnostic steps. If any of you have battled anything similar, please let me know if you agree of you have any ideas of definitely narrowing it down.

Symptoms
When driving the car at low speeds, there is no noise coming from the back end of the car. However, with the top on and driving at higher speeds there is definitely a constant noise coming from the rear right tire that increases and gets louder as the car goes faster. My vocabulary is a bit limited in how to describe this sound so the best I can come up with is a "warble". It is definitely a sound that has some sync with the rotation of the wheels. I figured it either had to be a wheel bearing or if I was interpreting what I read on here correctly, a torque tube bearing.

Diagnostics
I don't have a lift so I had to rely on driving. So my dad and I took it out down a road that I know is sparsely used and got it up to a high speed to start and then cut the engine and put it in neutral to try to eliminate the drive train from the equation. Sure enough, the noise still constant as we are going. Then as we were cruising down the road, I would sway the car right and swing the car left. If I swayed right with the weight on the right, the sound still persisted, if swayed left with the weight off of the right side the sound went away.

Am I on the right path? Any other diagnostic tips that others can share? Thanks in advance for any advice you can lend.

It sounds like it is likely a wheel bearing. If you're mechanically inclined enough that you want to attempt the repair yourself, I'd suggest jacking the car up and spinning each of the wheels in free air to see which sounds worse. You can typically hear a bad wheel bearing that way, and if not, you may need to take the brakes off to pinpoint where it's coming from.

You would possibly/likely have top and bottom play of the wheel as well. Basically, put a hand against 12 o clock and 6 o clock on the face of the tire and push one and then the other to see if there is play.

I agree you are on the right track. When I purchased my 2001 it had two rear wheel bearings making noise. I changed both and I could not believe the difference in the noise inside the car. My car had 140,000 miles when I purchased it,

What size rears are those?

Last time I tried this test, it was the right side that was bad even though swerving to the left made the noise go away. Loading the bearing more stopped the noise.

You could put the rear on stands, turn off the traction control and spin the wheels with the engine fast enough to hopefully hear it while outside the car.

I just wanted to put an update for everyone. Both bearings had some play. I ordered both rear (Timken per the recommendations of the board) and got them installed this week. The car drives like it is brand new now. It is probably best to replace both rear bearings if one starts to go. Thank you all for your help and responses.