2003 Whining near alternator - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 06-29-2010, 04:01 AM   #1
Newb
 
Join Date: Jun 2010
Posts: 4
2003 Whining near alternator

Hi,
My Jeep wrangler 2.4L whines loud (high pitch at high RPM, lower at low RPM). There
are no ghostly electrical problems (dims, can't start, etc.) Under the hood,
it seems to be coming from the alternator area. I read that an alternator can
whine if there's a bad ground. I checked all my aftermarket stereo equipment
and it's still there.

I took it to a Jeep dealer and they claimed they couldn't hear it. They came back to the waiting room and said they think they found it. A chipped pully and horizontally sliced belt. $300 later, they replaced both. Sound is still there and got worse.

What is best course of action? Can it just be the bearing of the alternator?

Thx

goldensaber is offline   Quote Quick Reply
Old 07-04-2010, 06:19 PM   #2
Newb
 
Join Date: Jun 2010
Posts: 4
UPDATE:

For future reference for anyone else, the problem was an idler pulley. The
bearings were shot. I've read an article online that this pulley isn't even needed,
and that the belt can be re-routed. However, it doesn't state what belt you'd need
to do this. Obiously, the original one is too long.

goldensaber is offline   Quote Quick Reply
Old 06-18-2014, 02:13 PM   #3
Jeeper
 
IslandTJ's Avatar
 
Join Date: Mar 2008
Location: where I wheel: N 45║ 36.663' W 123║ 20.935'
Posts: 2,812
Glad you had it resolved. Unexpected noises can be a pain.
__________________
1998 TJ Moss Green Sahara w/ numerous scratches & dents whose playground is on a tropical island that's 33 miles long and 4-12 miles wide, in year-round 82 degree weather

Edit: "Now jeepin in Oregon"
IslandTJ is offline   Quote Quick Reply
Old 06-19-2014, 10:41 AM   #4
Guest
 
Join Date: Oct 2013
Location: Augusta, Ga
Posts: 175
i have a similar noise on my 2001 jeep wrangler. Im thinking its the same thing, or at least similar with one of the pulleys. but its just this high, consistent, noise... its been there for a few months and i haven't been too concerned but its bothering just thinking about it now. the noise seems to get temporarily quiet when wet and then gets louder after a minute or two. is this a bad idler pulley? bad pulley tensioner? i do not have my car with me and haven't for about the past 2 weeks so i am unsure where the noise comes from exactly but i want to say it comes from closer to the alternator. any help?
xxxxxxxxxxptoncannon is offline   Quote Quick Reply
Old 06-20-2014, 02:14 PM   #5
Jeeper
 
IslandTJ's Avatar
 
Join Date: Mar 2008
Location: where I wheel: N 45║ 36.663' W 123║ 20.935'
Posts: 2,812
I have engine whine myself. The pitch and level go up as RPMs go up. I have not done anything yet but ignore the whine.
__________________
1998 TJ Moss Green Sahara w/ numerous scratches & dents whose playground is on a tropical island that's 33 miles long and 4-12 miles wide, in year-round 82 degree weather

Edit: "Now jeepin in Oregon"
IslandTJ is offline   Quote Quick Reply
Old 06-22-2014, 11:37 PM   #6
Guest
 
Join Date: Oct 2013
Location: Augusta, Ga
Posts: 175
Going to post a video tomorrow. Could someone who is familiar with this situation please help? Preferably someone who is young because I took it to my girlfriend's dad, who is a mechanic, and at about 50 could not hear anything... I'll see if I can enhance the sound after I record it but just really wanting to get rid of that noise. It's bothering me! Lol
xxxxxxxxxxptoncannon is offline   Quote Quick Reply
Old 06-23-2014, 12:04 AM   #7
Jeeper
 
Join Date: Oct 2011
Posts: 1,606
A bad alternator diode can cause a whine, similar to the sound of a ricocheting bullet.
tangofox007 is offline   Quote Quick Reply
Old 06-23-2014, 12:15 AM   #8
Guest
 
Join Date: Oct 2013
Location: Augusta, Ga
Posts: 175
It's a more consistent, high pitched whine... It's not like a it's a quick, repetitive noise. Just long and consistent, no breaks in the noise... Any idea what it could be?
xxxxxxxxxxptoncannon is offline   Quote Quick Reply
Old 06-23-2014, 08:19 AM   #9
Jeeper
 
Join Date: Oct 2011
Posts: 1,606
Quote:
Originally Posted by ptoncannon View Post
It's a more consistent, high pitched whine... It's not like a it's a quick, repetitive noise. Just long and consistent, no breaks in the noise... Any idea what it could be?
Everything in that description is consistent with diode noise.

Do you have a voltmeter that measures AC voltage? If so, check for AC voltage across the battery with the engine running.

You could also remove the belt and spin the various pullies by hand. Sometimes the problem gets real obvious when that is done.
tangofox007 is offline   Quote Quick Reply
Old 06-23-2014, 11:57 AM   #10
Jeeper
 
IslandTJ's Avatar
 
Join Date: Mar 2008
Location: where I wheel: N 45║ 36.663' W 123║ 20.935'
Posts: 2,812
Quote:
Originally Posted by tangofox007 View Post
A bad alternator diode can cause a whine, similar to the sound of a ricocheting bullet.
Aloha tangofox007, does the fix require the entire alternator to be replaced?
__________________
1998 TJ Moss Green Sahara w/ numerous scratches & dents whose playground is on a tropical island that's 33 miles long and 4-12 miles wide, in year-round 82 degree weather

Edit: "Now jeepin in Oregon"
IslandTJ is offline   Quote Quick Reply
Old 06-23-2014, 01:11 PM   #11
Jeeper
 
Join Date: Oct 2011
Posts: 1,606
Quote:
Originally Posted by IslandTJ View Post
Aloha tangofox007, does the fix require the entire alternator to be replaced?
No. The failed component(s) can be replaced.
tangofox007 is offline   Quote Quick Reply
Old 06-23-2014, 03:31 PM   #12
Jeeper
 
Dextreme's Avatar
 
Join Date: Oct 2011
Location: Oregon City, OR
Posts: 4,089
Images: 1
My alt whining was the belt on the alt pully. I pulled the serp belt and degreased all the pullys with carb cleaner. But the alt pully had caked on grease and dried mud/dirt in the grooves. I carefully cleaned the grooves with a small screw driver to get all the crap out... until it was clean as new.

Then I replaced the belt with a $26 Gates "W" belt and everything is quiet......ahhhhhh!
__________________
'99 Chilli Pepper TJ Wrangler "Mistress"
33x12.5 DuraTracs
Zone 4.25"
Dextreme is offline   Quote Quick Reply
Old 06-23-2014, 03:59 PM   #13
Jeeper
 
IslandTJ's Avatar
 
Join Date: Mar 2008
Location: where I wheel: N 45║ 36.663' W 123║ 20.935'
Posts: 2,812
Quote:
Originally Posted by Dextreme View Post
My alt whining was the belt on the alt pully. I pulled the serp belt and degreased all the pullys with carb cleaner. But the alt pully had caked on grease and dried mud/dirt in the grooves. I carefully cleaned the grooves with a small screw driver to get all the crap out... until it was clean as new.

Then I replaced the belt with a $26 Gates "W" belt and everything is quiet......ahhhhhh!
Mahalo Dextreme, I think I'll will try this...
__________________
1998 TJ Moss Green Sahara w/ numerous scratches & dents whose playground is on a tropical island that's 33 miles long and 4-12 miles wide, in year-round 82 degree weather

Edit: "Now jeepin in Oregon"
IslandTJ is offline   Quote Quick Reply
Old 06-24-2014, 11:13 PM   #14
Guest
 
Join Date: Oct 2013
Location: Augusta, Ga
Posts: 175
i tried to take a video but of course, when i started my jeep, the noise was as loud as ever and literally the second i pulled my phone out, of course the noise completely stops.. lol, i will hopefully be taking the belt off tomorrow if i can find the time to do so, and see if its caked up with grease and dirt, which i am sure it is, and while I'm at it ill degrease and re-grease all of the bearings.
xxxxxxxxxxptoncannon is offline   Quote Quick Reply
Old 06-25-2014, 07:01 AM   #15
Wild Willys!

WF Supporting Member
 
All Terrain JK's Avatar
 
Join Date: Jan 2013
Location: MI
Posts: 1,879
I have found a $10 mechanics stethoscope can be invaluable when tracking down engine noises.
__________________
Mama's: '14 JKU Freedom Billet Silver, Trail Rated
Mine: '15 JK Willys Wheeler Billet Silver, Trail Ready!
Roads? Where we're going we don't need roads!
Frame off TJ restore project
All Terrain JK is offline   Quote Quick Reply
Old 06-26-2014, 12:31 AM   #16
Guest
 
Join Date: Oct 2013
Location: Augusta, Ga
Posts: 175
Quote:
Originally Posted by All Terrain TJ View Post
I have found a $10 mechanics stethoscope can be invaluable when tracking down engine noises.
can you send me a link? that sounds great especially when you're working alone! lol, but just need to find the time to take it apart, especially since its my DD! also, tangofox007; how would you replace the alternator diode if that does end up being the problem? would that be a difficult task?
xxxxxxxxxxptoncannon is offline   Quote Quick Reply
Old 06-26-2014, 01:18 AM   #17
Jeeper
 
Dextreme's Avatar
 
Join Date: Oct 2011
Location: Oregon City, OR
Posts: 4,089
Images: 1
Harbor Freight has stethoscopes.
__________________
'99 Chilli Pepper TJ Wrangler "Mistress"
33x12.5 DuraTracs
Zone 4.25"
Dextreme is offline   Quote Quick Reply
Old 06-26-2014, 07:57 AM   #18
Jeeper
 
Join Date: Oct 2011
Posts: 1,606
Quote:
Originally Posted by ptoncannon View Post
also, tangofox007; how would you replace the alternator diode if that does end up being the problem? would that be a difficult task?
The diodes (6 ea) are part of the rectifier. Easiest option for most of us would be to replace the rectifier. I have not had a TJ alternator apart, but the ones that I have worked on were pretty simple.

The diode whine is pretty distinctive; sounds more "electronic" than mechanical, if that makes any sense. With a bad diode, the alternator should be putting out some AC current.

tangofox007 is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Alternator Harness? BossJelly Communications and Electronics 2 03-08-2010 12:00 PM
Got a Tricky Alternator Question!!! popatop YJ Tech Forum 7 06-10-2009 11:05 PM
Alternator is not providing a charge Beowulf TJ Tech Forum 1 05-05-2009 11:54 AM
HOWTO: Alternator Upgrade rketr TJ Tech Forum 5 09-19-2007 02:01 AM
alternator idiot light question GMR CJ Tech Forum 0 05-30-2007 10:59 PM



Download our Mobile App

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 07:28 AM.



Jeep«, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC