What could this noise be?

[vtl]

I don't really have a choice until I get a replacement part Monday or at best Tuesday.

I suppose the replacement part is engine?

Yes, kevlar threads of shredded aux belt can get behind t-belt, cause it skipping and potentially ruin the engine. I was lucky when my belt shredded, but it was only 1 tooth away from pistons slapping the valves.

[dikidera]

I know of this caveat with these engines. How careless of volvo to not properly protect them. Well, soon either way it will be replaced, but in my country shops dont work Saturday and Sunday.

[yanga001]

I know of this caveat with these engines. How careless of volvo to not properly protect them. Well, soon either way it will be replaced, but in my country shops dont work Saturday and Sunday.

It can happen with any timed engine unless the belts are on opposite sides. Maybe that was why the newer XC90's (by new i mean like 10-13) have their serpentine belt on the opposite side of the timing belt?

Ive heard of BMW's sucking serpentine belts through the crank seal and into the rotating assemblies before.

[cn90]

Remove the pulley (no need to remove the whole tensioner).
Gently lift the seal using a hook tool
Then press in some wheel bearing grease for now.
Reinstall the seal using thumb pressure.

Dry grease is the #1 cause of bearings failure.
Wheel bearings have more space for grease
Belt pulley has very little space for grease.

[cn90]

viewtopic.php?p=270356#p270356

[dikidera]

I just replaced the serpentine belt tensioner with a brand new one. Noise is still there so that leaves me with either AC compressor, hydraulic pump, crank pulley. Or it could still be the water pump but before when I removed the serpentine belt the noise was gone, however the engine was idling poorly so the conditions were different.

[Skymongrel]

Dealing with a similar noise on my XC70. Using a "stethoscope" , seems like my alternator is the loudest. I'm leaning towards the alternator. Haven't done any deep investigative work yet other than to listen and observe. I may pull the belt any start the car and listen for noise. Then see if I can feel anything unusual turning the different pulleys. I'm following your progress.

[jonesg]

spray ea pulley in turn with water, they squeak from heat friction, water cools them down just enough to stop the noise.
but without the belt it should be possible to feel it if you can hear it.
i drove 50 miles with no serpentine belt and headlights off, it still had to enough charge to start the car when i got home.