what exactly does a bad alternator sound like.

**FrimmelNoJerz** · 12-06-2007 09:59 PM

last week i started noticing this sound coming from the front of the car under light acceleration. it happens more so when the car isnt a hundred percent warmed up. to be perfectly honest it sounds almost like really large rodents squeaking under the hood. but after a while it just kinda...goes away. im getting the alternator replaced within the week so hopefully this cures it. the reason why i ask is because the same day i noticed the squeaking was the same day that that pesky upper driver side intercooler hose popped off again. and after i put it back on it started making noise. thoughts?

**Cole** · 12-07-2007 12:17 AM

A loose or glazed belt that is slipping just slightly when cold will cause the noise you describe. Alternators typically don't make any noise when they go bad. They just quit charging.

You can spray the belt with "belt dressing" found at any auto parts store and it should quit making noise.

**jakecro** · 12-07-2007 03:27 AM

^2nd...my alternator went bad a few months back; no noise just no charge

it could possibly be your belt tensioner, mine has a slight squeal to it, usually at idle and it will be a little louder when the A/C is on; after so long they will go bad. what is your mileage?

I wouldn't go replacing the alternator just cause you hear a noise unless you are 100% that it is the root of the problem

**BurnAll4S4** · 12-07-2007 04:23 AM

agreed. could be the tensioner going bad. alternators do make noise though and still be good. it can sound like chugging, or a screeching. test way to see if its the alternator is to take a long screwdriver and use it as a stethascope (sp?). one end on an engine piece and other end on your ear. put it on the block, alternator, etc. whereever it gets louder is your problem (yes this really works, i do it a lot at work when i cant pinpoint an engine noise).

**Cole** · 12-07-2007 03:53 PM

Originally Posted by XJinCT

.......take a long screwdriver and use it as a stethascope .

Yeah, it does work but have you seen where the alternator is on a S4?

**FrimmelNoJerz** · 12-07-2007 04:54 PM

haha its going to have to be a really long and curvy screwdriver. im posting the sounds in a minute on a new thread along witha few other problems. tell your friends.

**BurnAll4S4** · 12-07-2007 04:56 PM

lol yes ive seen where the alternator is. i did do my stage 3 by myself guys. you can access jam something up there i believe. *shrug*

**FrimmelNoJerz** · 12-07-2007 04:59 PM

i always squint really hard to see what that picture is as your avatar but i can never figure it out.

**rcjustin** · 12-07-2007 05:26 PM

santas getting owned

**AudiTechS4** · 12-07-2007 05:43 PM

hmm i dont know if hes really getting Owned :) I think hes giving the little helper a little gift

**rcjustin** · 12-07-2007 07:53 PM

eh, im not into the giving. even during the giving season. lol. Im on of those assholes who likes to recieve gifts. lol.

How did we get this far off track. lol

**AudiTechS4** · 12-07-2007 08:33 PM

hehe

to the ? above
we had a car yesterday that we couldn't pin point the noise but it sounded like a bad power steering pump. so we replaced it - not it - replaced the alternator - not it - replaced the belt tensioner- not it - replaced the idler puller - got it - this was on a 1.8
these noises trave so much its hard to figure out some times. take a 17 mm socket on a wrench and loosen the tension as someone is revving the motor dnd see if the noise goes away

**The_Jerbel** · 12-08-2007 08:38 AM

Originally Posted by Cole

Yeah, it does work but have you seen where the alternator is on a S4?

Or just spend the $10 and buy a mechanic's stethoscope ;)

When the alternator goes bad it sounds like your voltage meter reads low. haha

**kingofqueenz788** · 12-03-2010 12:25 AM

my a;tenators a tad bit loud too i gotta replace it, seemed louder after i power washed my bay i think water got inside possibly

**S4_NE** · 12-03-2010 05:44 AM

my alternator went bad in my STG 3 SDN, no noise at all just not chargie/volts to the Batt. Still waiting on fixing it... been driving my Avant more.

**SOFME** · 12-03-2010 05:58 AM

Originally Posted by AudiTechS4

hehe

take a 17 mm socket on a wrench and loosen the tension as someone is revving the motor dnd see if the noise goes away

not on a 2.7t you wont.

**shadwarr1** · 12-03-2010 07:15 PM

Damn, an almost 3 year old thread???

I wouldn't worry about the alternator making noise unless it annoys you. If it's still charging, leave it alone.