Whirring noise belt end motor

[Brendan W]

Aux idler. Snores when engine speed is changing. Could be anywhere until the hose is put next to it.
Loudest between 11 and 1200 rpm.

[Brendan W]

Update. Belt and tensioner assy replaced and the loud snore has gone. Both bearings seemed fine in situ, the tensioner pulley had a little rock but no noise, the idler seemed perfect. Now I can hear a high pitched noise. The joys of approaching the 150k mark.
The Volvo dealer did a good deal for me on the parts seeing as how I was messed about a bit. €100 for the tensioner and idler - not bad at all.

[cheshired5]

Have you tested the freewheeling of the alternator clutch pulley?

[Brendan W]

It's as good as new, new bearings in the alternator, p/s pump is quiet, fluid changed, no change when turning wheel, a/c pulley spinning free and quiet with the belt off. No noise with belt off so it is on the aux side of the house.Happier now the tensioner is new and the loud noise is gone. Hypochondria might be setting in. Think I'll keep an eye out for a recon p/s pump.

[cheshired5]

When you say it's as good as new, does the alternator pulley continue to turn clockwise by hand if you stick a screwdriver in the alternator fins?

[Brendan W]

I test it by flicking it both ways - one way is locked to the rotor the other has a smooth drag and a small amount of axial play. It's a Volvo replacement part fitted 48k ago. The tensioner is steady at idle as well. Starting to think replacement is the only real test for some of these things.

[cheshired5]

Originally Posted by Brendan W

Starting to think replacement is the only real test for some of these things.

Hmm, it's a tricky one. Your could replace 3 or 4 parts at the same time and sort it.....but you don't know which was the fix.........or you can keep going back and replacing one part at a time but that's a pain.
If you could capture the sound on a video, that may shed more light on things......