Alternator whines - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hirdo · 07-17-2009, 11:13 PM

I think my alternator is bad. Whines at high RPM. I'm pretty sure the belt is not too loose/tight. I think it was a cheapy. It only has 5,000 miles or so. Any suggestions on where to get a good one?

72 Longhorn
402 BB

BAGNDRAGIT · 07-17-2009, 11:24 PM

hmmm, are you sure its your alt? how high of an rpm? check it w/o the belt on, if it is i would say it was the alt bearing.

**leddzepp** · 07-17-2009, 11:24 PM

Riverside Air...on Indiana Ave here in Riverside. Arnie (or Ernie, can't remember his name now!) has been there for over 20 yrs. They rebuild alternators, starters, and A/C compressors on site. I had him rebuild/convert my alternator to a one wire, internally regulated unit. That was almost 5 yrs ago, and it still works perfectly. I think he is in the yellow pages under automotive A/C repair.

Sammy · 07-17-2009, 11:34 PM

I just installed a brand new delco CS130 ALT it has wine w/ serp system. Not saying yours isn't bad but I doubt mine is. Some whine, some don't.

mikajo39 · 07-17-2009, 11:45 PM

My old alternator whined pretty bad (sounded like I had a supercharger

) I just turned it in and got a NAPA replacement no more whining.

**El Jay** · 07-18-2009, 01:37 AM

Did you try using a stethoscope, long screwdriver, broom handle, etc. to try & track done the exact location of the whine to make sure it was the alternator?

**special-K** · 07-18-2009, 05:55 AM

It may be the alternator.But,my experience has been that when it`s a bearing the alt. makes noises at idle that sound marbley(marbles).

Sammy · 07-18-2009, 08:13 AM

special-K I agree. Besides we are only talking a $4 bearing here.

hirdo · 07-18-2009, 11:00 AM

Thanks for the ideas. I'll check it out!

**mr48chev** · 07-18-2009, 11:15 AM

It is most likely the bearing or bearings but you might want to pull the plug an run the truck without the alternator charging to see if the noise changes.

I'd do as El Jay suggested and see if I could find exactly where the noise is coming from first though.

Both bearings should come to under 20 bucks and brushes aren't that expensive if it needs them.

Mark the cases before you take it apart though as I at least always seem to forget exactly how it was before I took them apart.

07-17-2009, 11:13 PM	#1
hirdo Registered User Join Date: Apr 2005 Location: Southern Cal Mountains Posts: 14	Alternator whines I think my alternator is bad. Whines at high RPM. I'm pretty sure the belt is not too loose/tight. I think it was a cheapy. It only has 5,000 miles or so. Any suggestions on where to get a good one? 72 Longhorn 402 BB Attached Images

07-17-2009, 11:24 PM	#2
BAGNDRAGIT Just Not Low Enough! Join Date: Mar 2009 Location: Phoenix, AZ Posts: 525	Re: Alternator whines hmmm, are you sure its your alt? how high of an rpm? check it w/o the belt on, if it is i would say it was the alt bearing. __________________ NEED ELECTRICAL HELP? ASK ME! 67-72 Full Wiring Diagrams Lots Of Info, TAKE A LOOK 1967 Chevy C-10 Shortbox Bagged 327 4spd Previous: 1971 Chevy C-10 Short Sep I6 Auto (Traded) 1973 Chevy C-20 THE REDNECK BATTLE TRUCK 2001 Chevy Silverado 2Dr 5.3L Shortbox. R.I.P. 1969 Volkswagen Bug This is my first meeting, I have a horsepower problem.

07-17-2009, 11:24 PM	#3
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 20,020	Re: Alternator whines Riverside Air...on Indiana Ave here in Riverside. Arnie (or Ernie, can't remember his name now!) has been there for over 20 yrs. They rebuild alternators, starters, and A/C compressors on site. I had him rebuild/convert my alternator to a one wire, internally regulated unit. That was almost 5 yrs ago, and it still works perfectly. I think he is in the yellow pages under automotive A/C repair. __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man RIP FleetsidePaul Last edited by leddzepp; 07-17-2009 at 11:25 PM.

07-17-2009, 11:34 PM	#4
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: Alternator whines I just installed a brand new delco CS130 ALT it has wine w/ serp system. Not saying yours isn't bad but I doubt mine is. Some whine, some don't. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

07-17-2009, 11:45 PM	#5
mikajo39 Gearhead and audio junkie Join Date: Aug 2008 Location: nunyah Posts: 452	Re: Alternator whines My old alternator whined pretty bad (sounded like I had a supercharger ) I just turned it in and got a NAPA replacement no more whining.

07-18-2009, 01:37 AM	#6
El Jay Gone to greener pastures Join Date: May 2007 Location: Gateway to the Delta Posts: 7,354	Re: Alternator whines Did you try using a stethoscope, long screwdriver, broom handle, etc. to try & track done the exact location of the whine to make sure it was the alternator? __________________ '69 Chevy 1/2 T LWB Stepper: Daily Beater '72 GMC 3/4 T Fleet: Another Daily Beater '72 Plymouth Gran Coupe: ? "Ah women. They make the highs higher and the lows more frequent." Friedrich Nietzsche "Never kick a fresh turd on a hot day." Harry S. Truman GUN CONTROL: Never having to say, "I missed you." Always fire two warning shots into your attacker's chest area before putting a bullet between his eyes. Paraphrased from Louis Awerbuck

07-18-2009, 05:55 AM	#7
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: Alternator whines It may be the alternator.But,my experience has been that when it`s a bearing the alt. makes noises at idle that sound marbley(marbles). __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

07-18-2009, 08:13 AM	#8
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: Alternator whines special-K I agree. Besides we are only talking a $4 bearing here. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

07-18-2009, 11:00 AM	#9
hirdo Registered User Join Date: Apr 2005 Location: Southern Cal Mountains Posts: 14	Re: Alternator whines Thanks for the ideas. I'll check it out!

07-18-2009, 11:15 AM	#10
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,639	Re: Alternator whines It is most likely the bearing or bearings but you might want to pull the plug an run the truck without the alternator charging to see if the noise changes. I'd do as El Jay suggested and see if I could find exactly where the noise is coming from first though. Both bearings should come to under 20 bucks and brushes aren't that expensive if it needs them. Mark the cases before you take it apart though as I at least always seem to forget exactly how it was before I took them apart.

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