XM 2.5 (Non A/C) Aux. Belt

[rg]

Folks,
This was replaced at the 72K service, has been re-adjusted once, and now squeals at start up for around 20 secs (usually in damp conditions. Then disappears.
Not deafening but irritating, and enough for the neighbours to think "Why does he not part-ex that ugly French banger for a nice Toyota Yaris?"
A/ Are there any horrors to watch with the adjuster? As in it drops off its thread (surprisingly quickly) and falls into the dark depths?
B/ Has anyone else had experience of belts needing taking up twice in such a short time?
C/ Could this point to a pump/alternator beginning to fail?
D/ Maybe I should just go out and do the thing instead of fretting
E/ How much tension should this belt take (Haynes says 5mm at longest stretch)
F/ All of the above
G/ None of the above
Cheers
rg

[JohnD]

Usually, when a belt sqeals it's a sign of insufficient tension. Tighten it up until you only have 5mm of movement in the longest belt run.