volvo hum (no not the song!) 2009 C70

[cudavid]

Ok, wife's car, 65K , shares same platform as the 40 and 50 / 60 Volvo series cards I think.
Humming noise getting louder in past 6 months. I bet front wheel bearings and planned them some day, well then BOTH axle boots split between oil changes and spewed grease, ok, do new high quality GNK axles and SKF bearings(OEM), at same time.
No real change!

Ok must be tire noise, 25K on tires, did rotate again, no change, ok, screw it, new tires, no change!
Back wheel bearings feel fine, but will do them this weekend.
If this fails what next!. GRRRR

 

[meep]

does hum:
change with speed?
change with engine rpm?
change with gear?
change with load?
do it in neutral?
change with steering input?
change with brake input?

 

[mk378]

If you can hear it at low speed, stand outside the car and have someone drive past you while you listen to try to localize the noise source.

 

[AndyB]

Possible to jack up car and put on jack stands? You could then run it in gear and pinpoint the sound?

 

[Lolvoguy]

Just make sure it's not coming from the engine.
If it's noticeable when the car is idling in place, I'd seriously suggest looking into getting the PVC system REPLACED. Failure to do so will result in blown engine seals.

 

[14Accent]

Does the passenger side axle have a stub shaft with a carrier bearing? That's my bet if it does.

*edit* Looks like the axle and bearing are one piece. Scratch that. I would look into the PCV as well. With the engine running and the noise happening, pull the oil cap. Is there excessive vacuum? Does the noise stop?