Volvo v70 cross country

[TonyP]

My volvo makes this weird howling noise when I drive it. Sometimes its loud sometimes its not. Sometimes it does it, sometimes it doesnt. It doesnt seem to effect the performance of the car but can be a bit annoying. Any ideas?

[JRL]

Please try to be a bit more specific
A "howling noise" is a bit hard to diagnose over the web
When does it do this, (speed and exact driving conditions,) how often, how loud, etc
Driving straight
During turns

Could be a bad wheel bearing
Cound be the bevel gear
Could be the propshaft
Could be the Viscous coupling

Could be many things.
Try to determine where in the car the sound is coming from. I know sounds travel and you may need another set of ears while you're driving
or take a sound clip and post it here

Also your year, your mileage etc

[TonyP]

it has about 149,000 and I know its not a wheel bearing. but it can be very loud and it starts at about 25 mph. comes and goes, I've been reading your replys and you seem to be the guy that would know. Its unusual and like I said, it doesnt seem to be a problem other than the noice. It doesnt matter what speed Im going it usually does it.

[JRL]

Again..
Straight
Turning when?
Either you're propshaft, bevel gear or viscous coupling is starting to go or it's an engine deal
But "howling" is not a description, you need to be more specific or take a clip and post it on You Tube and link it here