A4 (B5 Platform) Discussion Discussion forum for the B5 Audi A4 produced from 1995-2001 B5 FAQ

Bearing whirring noise from alternator area. Alternator or fan clutch???

Old 07-29-2008, 04:36 AM
  #1  
Junior Member
Thread Starter
 
über güber's Avatar
 
Join Date: Jan 2007
Posts: 543
Likes: 0
Received 0 Likes on 0 Posts
Default Bearing whirring noise from alternator area. Alternator or fan clutch???

I can't tell where the noise is coming from... alt. or fan clutch?
Sound is too high to be wpump.

I released the serp belt and gave the alternator a spin, and you could
definatley hear the bearings rattling around... but now
I'm not sure and alternators are expensive as are fan clutch,
so I'm trying to be accurate in my diagnosis.

About 10k ago I did full tbelt kit, wpump, tstat, belts, and most
recently the serp belt tensioner.

Thanks!
Old 07-29-2008, 05:49 AM
  #2  
Junior Member
Thread Starter
 
über güber's Avatar
 
Join Date: Jan 2007
Posts: 543
Likes: 0
Received 0 Likes on 0 Posts
Default I sprayed what I could with WD/40, sound went away briefly but came back.

I managed to get behind fan pulley/clutch as well as spraying
the alt. but nothing happened. The noise did go away briefly, and
I tried to do it in succession, alt. first then wpump.
So I'm not exactly sure where it's coming from.

I'm alleviated that it's not coming from the tbelt area!

Still confused.
Old 07-29-2008, 07:03 AM
  #3  
AudiWorld Member
 
mktbully's Avatar
 
Join Date: Jan 2006
Posts: 509
Likes: 0
Received 0 Likes on 0 Posts
Default if you spin the alternator w/ the belt off and it rattles...

it'll sound worse w/ the belt ON.
sounds like you need a new alternator or you can try replacing the bearings on your old one.
Old 07-29-2008, 07:05 AM
  #4  
AudiWorld Member
 
mktbully's Avatar
 
Join Date: Jan 2006
Posts: 509
Likes: 0
Received 0 Likes on 0 Posts
Default

ok why not isolate it by spraying just the alt and see if the noise goes away?
Old 07-29-2008, 07:18 AM
  #5  
AudiWorld Super User
 
Audi Junkie's Avatar
 
Join Date: Nov 2001
Posts: 19,232
Received 9 Likes on 8 Posts
Default

Try some belt dressing.
Old 07-29-2008, 07:20 AM
  #6  
Junior Member
Thread Starter
 
über güber's Avatar
 
Join Date: Jan 2007
Posts: 543
Likes: 0
Received 0 Likes on 0 Posts
Default Why belt dressing? Do you think it's the belts? Not the belts I can assure you.

Or do you think the belt dressing is going to act as a lubricant?
(Not being a smart ***.)
Old 07-29-2008, 07:21 AM
  #7  
Junior Member
Thread Starter
 
über güber's Avatar
 
Join Date: Jan 2007
Posts: 543
Likes: 0
Received 0 Likes on 0 Posts
Default

Kinda what I figured, just not 100% sur. Bearings on the alt sounds like a scary job (press needed?)
Old 07-29-2008, 07:24 AM
  #8  
Junior Member
Thread Starter
 
über güber's Avatar
 
Join Date: Jan 2007
Posts: 543
Likes: 0
Received 0 Likes on 0 Posts
Default Right did that 1st time, but nothing <immediately> happened until after

everything was soaked at that point, thus I made it much harder
for myself to pinpoint.

But I'll try it again, just on the alt this time.
Old 07-29-2008, 08:13 AM
  #9  
Junior Member
Thread Starter
 
über güber's Avatar
 
Join Date: Jan 2007
Posts: 543
Likes: 0
Received 0 Likes on 0 Posts
Default

Followup to spraying alternator: no improvement
Old 07-29-2008, 08:42 AM
  #10  
AudiWorld Super User
 
Audi Junkie's Avatar
 
Join Date: Nov 2001
Posts: 19,232
Received 9 Likes on 8 Posts
Default

Either way the belts will quiet down enough to hear what the source is.

Thread Tools
Search this Thread
Quick Reply: Bearing whirring noise from alternator area. Alternator or fan clutch???



All times are GMT -8. The time now is 01:14 AM.