Hi, I know it probably is a classic topic here in the forum, I've read lot of threads regarding the wheel bearing debate. And now I am actually having one!

I have a 2004 S60 2.5T AWD, I've put 30,000km on this baby since I got it on 100,000km, I noticed a rotational humming sound from the rear right on day 1 and I thought it was the low profile sport tyres (235/45R17). When time goes on, it gradually developped and now it is more pronounced at lower speed, most noticable at 50-60km/h. It comes from the rear right (I tried to sit in the back seat changing my position in between the left and the right, it is louder in the right) and its frequency changes related to the speed of the vehicle.

Here's what I have done so far:

At 126,000km I had the car booked for an oil change at my Volvo dealer, I change oil every 6,000km despite Volvo recommends every 12,000km. The dealer told me that I had two wheel bearings started to go, one on the left driver's front and one on the right rear. Dont know how did they test the bearings but I don't hear a thing from the front anyways. I didn't let them replace them as I wanted to have the tyres replaced first to rule out the tyres.

Two weeks ago, I had all 4 tyres replaced and did computer alignment, brand new Conti Extreamcontact, very nice tyres by the way. (found uneven wear on the old ones especially on the inside, they were rotated regularly, they did cause some vibration at 90-110km/h as some of them have lumps on the tread, the front and rear toe was a bit off too, car pulls to the right on high ways) The road noise is significantly decreased and the controling is better than before especially the steering, it does not pull to the right any more, but the rotational humming noise is still there. :blush:

Then I started to test the wheel bearings by listening to the noise when doing sharp left and right turns at an empty parking lot. The noise dose NOT change when the bearing is loaded or unloaded partially.

I had a service tec test drive the car and he said it does not sound like wheel bearing to him, it could be brake pads (I also noticed that S60R has the famous pads resonance sound), but the sound dose NOT change tone or disappear when the brake (He tried both service or parking) is applied.

It gets a bit louder than before but still not unbearable yet, and it seems not noticable in the cold morning and gets worse when the ambient temp goes up in the afternoon.

What can the next step be to find the root cause, I don't want to replace parts without solving the problem. I will try to put the car on the hoist let all wheels off the ground and drive it in gears, I suppose the rear wheel will rotate as it is an AWD and I can sit in the car to listen if the humming is still there, if it is not, it rules out the brakes and drive shafts or tranny, then I will go ahead to replace the rear right wheel bearing. If it is still there, I will have the brakes and drive shaft inspected.

What do you guys think? Any suggestions? Could that be normal on AWDs? It bothers me more and more since I noticed it and I can't help pay attention to it every time when I am driving in the car. :57:

Thanks alot! :liebe011: