Alternator Bearing?

1. RS-Williams Newbie Joined: Sep 2011 Northamptonshire Posts: 11 Saxo VTR

   #1 1st November 2011, 21:08

   Yesterday started to hear a low, engine speed related hum coming from what I suspect to be the alternator, not 100% but its coming from that area. Firstly thought it was the alternator bearing starting to go. But having a quick look round I cant feel any play when I move it, and the strange thing is it goes away once the car has properly warmed up. Now a knackered bearing would not do this (to my knowledge) to does anybody have any clues?
   
   Don't want the alternator collapsing in the next few days/weeks as I've got 2 400 mile trips coming up and if I need another alternator better get one asap.
   
   Any help appreciated
   
   Thanks
   Sion
2. user_20080 Saxperience Hardcore! Joined: Dec 2007 smurfland. Posts: 17346 Ex saxo owner.

   #2 1st November 2011, 22:25

   An alternator bearing in my experience wouldn`t hum,it`d squeal(unless it knew the words)joke.
3. Stevo123 Established Member Joined: Apr 2009 Redcar Posts: 1971 2000 Posi Blue vtr

   #3 1st November 2011, 22:49

   Cambelt tensioner pully is likely or poss, but less likely, waterpump. Why not take alternator belt off to rule the alternator out? Waterpump would likely leak water as it gets worse-dont leave it though
4. RS-Williams Newbie Joined: Sep 2011 Northamptonshire Posts: 11 Saxo VTR

   #4 2nd November 2011, 11:48

   Is the water pump at the front of the engine? Can't see much underthere now as when I go and come from work its dark.
   
   Had a little listen today and its deffo coming from the alternator area not the rear but by the time I got to work (approx 15 miles city and main roads, so nice and warm) it was gone
5. iSlayeR Established Member Joined: Aug 2009 King's lynn Posts: 2073 Turbocharged vtr

   #5 2nd November 2011, 12:28

   Any service history when waterpump/cambelt was last done? I had a high pitched sound coming from my cambelt, so i changed the whole lot, cambelt/water pump/alt belt.
6. RS-Williams Newbie Joined: Sep 2011 Northamptonshire Posts: 11 Saxo VTR

   #6 2nd November 2011, 12:33

   No service history with it (was cheap) unfortunatly, but the belt has been changed within the last year as it looks relatively new as does the alternator belt. It's not really a high pitched noise its a constant hum that changes with engine RPM more than anything, kinda like a wheel bearing is the best way to describe it.
   
   Its the fact that it goes away when warmed up that baffels me
   
   Thanks
7. Stevo123 Established Member Joined: Apr 2009 Redcar Posts: 1971 2000 Posi Blue vtr

   #7 2nd November 2011, 12:57

   If it is a like 'wizzing' noise (sound a bit like an electric motor instead of a petrol engine when revved) could well be the cam belt too tight. Just needs a tiny bit of adjustment. Not a mega problem, just get it doneover the next few weeks or so. Will ease off when warm because the belt will be ever so slightly bigger when warm due to expanding a tiny bit