Alternator rattle
Alternator rattle
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DB S3

Original Poster:

49 posts

278 months

Wednesday 28th April 2004
quotequote all
Guys would be grateful for any thoughts -

Had the S3 for nearly 18 months now. Been a real joy ! Just recently its started making a weird kind of rattling noise though, but not all the time and not that loud.

Pulled the hood up the other day, engine ticking over, noise sounds like its coming from the alternator i think. What's strange is that when i pull the alternator up(ie away from the floor, thus tightening the tension in the fan belt), the noise stops.

At first i thought the alternator just needed re-fixing in to position. For a week, this sorted the problem, but last night the damn noise came back. Quick inspection of suspect area, doesn't look like the alternator has slipped on it's bracket.

Also, the voltmeter is reading fine - charging at 11-13v i think (after taking revs over 2200 per the bible).

I was wondering if there are some 'bearings' internally in the alternator that may be wearing. If so i need to fit a new one - doesn't look too difficult (read bible and done search on forum). Seems like it could be anyone of about 3/4 different models though !!!!

However, before i rush off head-long into that, i was wondering if anyone on here has experienced anything similar or might have alternative suggestions about what to look at.

Any help really appreciated, thanks in advance

DB

>>> Edited by DB S3 on Wednesday 28th April 21:01

trevytrev

94 posts

279 months

Wednesday 28th April 2004
quotequote all
Sounds similar to a problem I had, I thought the bearings were going in my alternator, but I found that when I sprayed the fan belt with WD40 the noise went away. So I bought a new fan felt and its been fine ever since

Strange though because I can't work out what is wrong with the old one to cause the noise !!..

Trev

Roy C

4,209 posts

307 months

Thursday 29th April 2004
quotequote all
Do the cheap thing first - Change the belt
(and make sure the new one doesn't cut into the top water hose, which is close).

andyf007

863 posts

281 months

Friday 30th April 2004
quotequote all
Have you ruled out the water pump?

DB S3

Original Poster:

49 posts

278 months

Tuesday 4th May 2004
quotequote all
tried the wd40 trick over the weekend

sprayed the whole suspect area (fan belt, alternator and water pump) - regrettably that just resulted in a plume of smoke (burning off wd40 !!!!!) when i started the engine - you can imagine the comments and chuckles from my girlfriend !!!!

next attempt - replace the fanbelt tomorrow evening

not completely ruled out the water pump, but the noise definitely sounds like its coming from the alternator