Dreaded Alternator Whine - Except it's not the alternator.

Heads, valves, pistons, rods, crankshaft, etc...

Moderators: Helpinators, Moderators

Post Reply
dumpedwagon
In Neutral
Posts: 11
Joined: Thu Dec 16, 2010 8:55 pm

Dreaded Alternator Whine - Except it's not the alternator.

Post by dumpedwagon »

Hey all. Last Saturday, I was driving back from a Welding class and stopped to put in some gas at a Shell station. Put in $20 and headed on my way. I heard a funny noise but thought it was the old f150 in front of me. Eventually, a gap formed between us and I realized the noise was coming from me so I pulled over immediately.

It's a RPM-dependent whine/whistle that almost sound like a really loud turbo :lol:

Was coming directly from the alternator so we popped in another one and to our dismay, it is still there.

Have done a lot of research online and everybody says it's something different. One guy said he had the whole entire motor rebuilt and it was still there (finally decided to just give up because he said he liked the sound as it sounded like a "rally car").

Car is a 1992 Legacy Non-Turbo. I have done the research with no luck and was wondering if any of you have come upon this same problem and how you resolved it.

I apologize for the long post . Also, thanks in advance for taking the time!

-Dan.


Edit: I've done some more research on this site. Seems like usually the noise goes away for most people after the car warms up. Mine does not.
kimokalihi
Fifth Gear
Posts: 8360
Joined: Mon Nov 06, 2006 3:41 am
Location: Tenino, WA

Re: Dreaded Alternator Whine - Except it's not the alternato

Post by kimokalihi »

The noise is under the hood and not inside the car? Could be an idler or any of the pulleys. Including ac and power steering. If you hear it inside it could be coming through the speakers. Had alternator whine before when I had unshielded rca cables on a power wire for my amp.
98 Metro Hatch Daily Driver :)
91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson
vrg3
Vikash
Posts: 12517
Joined: Sun Nov 03, 2002 2:13 am
Location: USA, OH, Cleveland (sometimes visiting DC though)
Contact:

Re: Dreaded Alternator Whine - Except it's not the alternato

Post by vrg3 »

Yeah, I agree it's likely to be one of the other accessory pulleys -- the power steering pump, the A/C compressor, or the A/C compressor idler.

I would take off both the alternator/PS belt and the A/C compressor belt and feel how smoothly all the pulleys turn. You may find one that's obviously bad. If you don't, try starting the engine without those belts. You can safely run the engine for several minutes without the alternator. If the whine is gone, then put the belts on one at a time to narrow down the problem.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
powerofone
In Neutral
Posts: 16
Joined: Mon Jan 23, 2012 7:03 pm
Location: pa

Re: Dreaded Alternator Whine - Except it's not the alternato

Post by powerofone »

Could also be one of the timing belt pulleys because two of them are directly under the alt.
1993 legacy sport ej20k and 5 speed from sti. W.I.P.
1997 legacy L 2.5 w/ 2.2 heads hybrid ,auto daily driver
1996 impreza 2.2 auto gfs car
1987 GMC suburban 1 ton truck suspension, duelly, 6.2 diesel, banks Turbo kit, 5 speed
dumpedwagon
In Neutral
Posts: 11
Joined: Thu Dec 16, 2010 8:55 pm

Re: Dreaded Alternator Whine - Except it's not the alternato

Post by dumpedwagon »

Yes sir, the noise is definitely from under the hood. It sounded like it was coming directly from the alternator, which is why we replaced it.

We had a similar noise about a year back but not as bad. It did turn out being the power steering pump, which was replaced and it went away. The noise from the power steering was almost inaudible. You could only hear it on dead streets (no noise). This new whine is very loud.

Now that I think about it, we did start the engine for about 30 seconds after pulling off the belt that ran on the alternator but shut if off without listening closely. I guess that's we'll do next when the weather gets better. We'll pull off all the belts and see where the noise is coming from. Do you guys think there will be any problem driving the car as is? Guess it depends on what is actually "broken".

As I said, I'll do the belt/pulley test when the weather gets better and I'll report back. Thanks for the help guys!
powerofone
In Neutral
Posts: 16
Joined: Mon Jan 23, 2012 7:03 pm
Location: pa

Re: Dreaded Alternator Whine - Except it's not the alternato

Post by powerofone »

Yea unhook the alt belt and AC belt start it if you still hear the noise I wouldn't run it because it will be a good chance its one of the timing belt idlers and the timing belt could break but if the noise goes away just put the AC belt on and try it and if it still don't make the noise it will almost have to be your power steering pump since your alt is new
1993 legacy sport ej20k and 5 speed from sti. W.I.P.
1997 legacy L 2.5 w/ 2.2 heads hybrid ,auto daily driver
1996 impreza 2.2 auto gfs car
1987 GMC suburban 1 ton truck suspension, duelly, 6.2 diesel, banks Turbo kit, 5 speed
Legacy777
Site Admin
Site Admin
Posts: 27926
Joined: Tue Oct 15, 2002 11:37 am
Location: Houston, Tx
Contact:

Re: Dreaded Alternator Whine - Except it's not the alternato

Post by Legacy777 »

I'd suspect the power steering pump. Check how smoothly it rotates. It should rotate very smoothly.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
Inlinesicks
In Neutral
Posts: 25
Joined: Tue Jun 15, 2010 12:17 am
Location: Palm Desert, Ca

Re: Dreaded Alternator Whine - Except it's not the alternato

Post by Inlinesicks »

I had the same whine, turned out the timing cover got a little tweaked and was rubbing on the timing belt.
2000 BMW 323i
1991 Subaru Legacy ss
1990 Jeep Cherokee 4.0 4x4
1986 Toyota pickup 3.0L turbo diesel 4x4
Post Reply