Alternator?
Thread Starter
Instructor
Joined: May 2007
Posts: 177
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From: Spring TX
Alternator?
I bought my first Vette just a few weeks ago so I'm still learning my way around it - it's a 1989 with the manual transmission. Shortly after leaving the house this evening, I was sitting at a stoplight when I noticed that my dash lights were dimming in time with the blinker (they would dim, then get bright, then dim, etc). I then noticed the little battery icon was lit up so I flipped the switch to show me the Voltage reading on the dash and it was at 13.5. I shut off the headlights, but by the time I got back to my house less than 10 minutes later, the voltage was down to 10.8.
I am assuming the alternator has gone out, but wanted to see if there is anything else I should check as well? If it is the alternator, are there any "gotchas" I need to watch out for when replacing it, or is it pretty straightforward?
Also, will an alternator from O'Reilly's, AutoZone, etc work fine, or do I need to get one from GM?
I am assuming the alternator has gone out, but wanted to see if there is anything else I should check as well? If it is the alternator, are there any "gotchas" I need to watch out for when replacing it, or is it pretty straightforward?
Also, will an alternator from O'Reilly's, AutoZone, etc work fine, or do I need to get one from GM?
Last edited by jeebs; May 8, 2007 at 11:25 PM. Reason: Additional info needed
Advanced
Joined: Aug 2006
Posts: 96
Likes: 0
From: Spokane Washington
I bought my first Vette just a few weeks ago so I'm still learning my way around it - it's a 1989 with the manual transmission. Shortly after leaving the house this evening, I was sitting at a stoplight when I noticed that my dash lights were dimming in time with the blinker (they would dim, then get bright, then dim, etc). I then noticed the little battery icon was lit up so I flipped the switch to show me the Voltage reading on the dash and it was at 13.5. I shut off the headlights, but by the time I got back to my house less than 10 minutes later, the voltage was down to 10.8.
I am assuming the alternator has gone out, but wanted to see if there is anything else I should check as well? If it is the alternator, are there any "gotchas" I need to watch out for when replacing it, or is it pretty straightforward?
Also, will an alternator from O'Reilly's, AutoZone, etc work fine, or do I need to get one from GM?
I am assuming the alternator has gone out, but wanted to see if there is anything else I should check as well? If it is the alternator, are there any "gotchas" I need to watch out for when replacing it, or is it pretty straightforward?
Also, will an alternator from O'Reilly's, AutoZone, etc work fine, or do I need to get one from GM?
I wouldn't worry about buying an alternator from any of the major supply stores except that some of their rebuilds aren't done too well. You never know which one will be the lemon. Most of those stores have a good warranty so you are safe. Gary R
Pro
Joined: Nov 2006
Posts: 638
Likes: 0
From: Plano TX
I wouldn't necessarily say it's the alternator right off the bat. Have you tried to load the system up to see what kind of dip you take?
Also, our digi dashes have been known to cause battery drain when the power supplies start to crap out. You might want to take a look at some of those things before axing the alternator.
Also, our digi dashes have been known to cause battery drain when the power supplies start to crap out. You might want to take a look at some of those things before axing the alternator.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
If the battery symbol light came on, your alternator is not charging your battery. The alternator could be defective, but there is also a fusible link in the output wire that should be measured. Measure the resistance from the positive battery post to the alternator output bolt. It should measure the same resistance as when touching the ohmeter probes together. If ok, then your alternator is toast. It is pretty easy to replace the alternator by yourself.
Pro
Joined: Nov 2006
Posts: 638
Likes: 0
From: Plano TX
If the battery symbol light came on, your alternator is not charging your battery. The alternator could be defective, but there is also a fusible link in the output wire that should be measured. Measure the resistance from the positive battery post to the alternator output bolt. It should measure the same resistance as when touching the ohmeter probes together. If ok, then your alternator is toast. It is pretty easy to replace the alternator by yourself.
He said he flipped to volts and saw it was reading 13.5 volts.
Can the ECM in these actually sense when the alternator, or possibly fusible link, is crapped out? I always though the battery indicator would only come on when your battery dipped below a certain voltage.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
altenator
take the battery lead off your alternator, and start it up. flip to volts, make a mental note, and then flip it to where the volts is not displayed, Sit back and watch. the computer will display the problem, and you will have a chirp in the speaker if the radio is on. Be sure to recharge your battery with a battery charger, not the alternator.
Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
Get yourself a cheap Multimeter, you can get one for less than $20.00. Measure your battery voltage with the engine OFF. You should see over 12 volts (12.5 or so) If you see less charge the battery. If it will not take a charge and bring the voltage up replace it. With a good hot battery start the car, now measure battery voltage. It should have come up to 13.5 to almost 15. If not you have a problem in the charging circuit. It could be anything from a loose/dirty/corroded connection to a bad wire or a bad alternator. If you do not see good voltage at the battery try measuring at the back of the alternator, if you see good voltage here you have a back connection between the alternator and the battery. Most Autozones will test the alternator off the car as well as in the car for free if you don't want to fool around with it.
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Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
The only way to find the problem is to measure voltage at every possible voltage drop location. Only after all possible problem area's have been eliminated do you start replacing things.
If you measure the voltage at the back of the alternator, that is a pretty good indication of it's condition.
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
I had exactly the same thing happen on my 1989 right after I bought it. It was a SLIGHTLY loose cable connection at the battery. Check and clean all connections and charge the battery, then see how it does. If you want to get one locally Autozone has Duralast Gold with a lifetime warranty.
Last edited by BADDUCK; May 9, 2007 at 09:17 AM.
Race Director
Joined: Oct 2001
Posts: 19,653
Likes: 428
From: Melbourne Florida
Cruise-In IV Veteran
My dash turned into disco vette one time...turned out to be the voltage regulator...on my 93 it is all one unit with the alternator...I went ahead and put in a 140 amp and no problems since...
I cannot state stronly enough for you to NOT mess with the parts stores rebuilds...yes, they have warranties but what good are those when you are stranded on the side of an I road at midnight in the middle of nowhere?...and this happens to you 3 times in one month?...ask me how I know...suck it up and get a genuine AC/Delco unit..pricey but you will not regret it...
I cannot state stronly enough for you to NOT mess with the parts stores rebuilds...yes, they have warranties but what good are those when you are stranded on the side of an I road at midnight in the middle of nowhere?...and this happens to you 3 times in one month?...ask me how I know...suck it up and get a genuine AC/Delco unit..pricey but you will not regret it...
Team Owner
Joined: Jun 2001
Posts: 26,196
Likes: 0
From: Orlando FL
St. Jude Donor '08-'09
Ive replaced mine multiple times over the years.
Remove it and have it tested as advised above. Any autoparts store can usually do this for you. Just call ahead to make sure that paticular store has an alternator in stock in case it is bad so you dont have to make multiple trips.
One trick I learned was... make sure to either test or charge the battery fully. I had 3 combos (batt/alt) in a row die on one car because one was bad and ruined the other back and forth.
Get yourself one of those $15 tensioner tools (for removing the belt with) from Discount or Autozone. You can get away without one, which I did for years, but I finally bought one and could not believe I never spent the money to make my life SOOO much easier.
Swapping out alternators takes no more than 30 mins tops or if you've done it before, 15 mins heh
Your problem is *usually* a bad alternator or battery.. I'd lean toward removing and testing the alternator as your very first step (after checking to make sure all the cables are clean, connected firmly, etc).
Remove it and have it tested as advised above. Any autoparts store can usually do this for you. Just call ahead to make sure that paticular store has an alternator in stock in case it is bad so you dont have to make multiple trips.
One trick I learned was... make sure to either test or charge the battery fully. I had 3 combos (batt/alt) in a row die on one car because one was bad and ruined the other back and forth.
Get yourself one of those $15 tensioner tools (for removing the belt with) from Discount or Autozone. You can get away without one, which I did for years, but I finally bought one and could not believe I never spent the money to make my life SOOO much easier.
Swapping out alternators takes no more than 30 mins tops or if you've done it before, 15 mins heh
Your problem is *usually* a bad alternator or battery.. I'd lean toward removing and testing the alternator as your very first step (after checking to make sure all the cables are clean, connected firmly, etc).
Last edited by GIJoe; May 9, 2007 at 10:12 AM.
Le Mans Master
Joined: Dec 2002
Posts: 6,715
Likes: 2
From: Santa Teresa New Mexico
My dash turned into disco vette one time...turned out to be the voltage regulator...on my 93 it is all one unit with the alternator...I went ahead and put in a 140 amp and no problems since...
I cannot state stronly enough for you to NOT mess with the parts stores rebuilds...yes, they have warranties but what good are those when you are stranded on the side of an I road at midnight in the middle of nowhere?...and this happens to you 3 times in one month?...ask me how I know...suck it up and get a genuine AC/Delco unit..pricey but you will not regret it...
I cannot state stronly enough for you to NOT mess with the parts stores rebuilds...yes, they have warranties but what good are those when you are stranded on the side of an I road at midnight in the middle of nowhere?...and this happens to you 3 times in one month?...ask me how I know...suck it up and get a genuine AC/Delco unit..pricey but you will not regret it...
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
With all this sage advice I am reluctant to jump in but: Drive to a decent auto electrical shop, have them test the alternator and battery. If the alternator is bad they can/will rebuild it while you wait. There are three components that are the most common to fail, Diode trio, regulator and brushes. Local shop, a high quality bunch, will rebuild one for $65.00 with a forever warranty.
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
My dash turned into disco vette one time...turned out to be the voltage regulator...on my 93 it is all one unit with the alternator...I went ahead and put in a 140 amp and no problems since...
I cannot state stronly enough for you to NOT mess with the parts stores rebuilds...yes, they have warranties but what good are those when you are stranded on the side of an I road at midnight in the middle of nowhere?...and this happens to you 3 times in one month?...ask me how I know...suck it up and get a genuine AC/Delco unit..pricey but you will not regret it...
I cannot state stronly enough for you to NOT mess with the parts stores rebuilds...yes, they have warranties but what good are those when you are stranded on the side of an I road at midnight in the middle of nowhere?...and this happens to you 3 times in one month?...ask me how I know...suck it up and get a genuine AC/Delco unit..pricey but you will not regret it...
This advice couldn't be better. I purchased one of those lifetime alternators and after replacing it four times within two years, I finally bought an OEM. And then the replacements stopped. I think the rebuilds are being rebuilt blindfolded by children.
Le Mans Master
Joined: Dec 2002
Posts: 6,715
Likes: 2
From: Santa Teresa New Mexico
With all this sage advice I am reluctant to jump in but: Drive to a decent auto electrical shop, have them test the alternator and battery. If the alternator is bad they can/will rebuild it while you wait. There are three components that are the most common to fail, Diode trio, regulator and brushes. Local shop, a high quality bunch, will rebuild one for $65.00 with a forever warranty.
Le Mans Master
Joined: Dec 2002
Posts: 6,715
Likes: 2
From: Santa Teresa New Mexico
Ok, since were giving out good advice, I had my trans fluid changed at 41,000 miles. The guy who owns the shop, a senior, said he changes his trans fluid every time he changes his engine oil. He uses Amisol and he changes it every 15,000 miles.
He said in the 24 years he's had the trans shop hes never had a trans of his fail.
I thought the dam things went 100k to 125k and just burned out.
Not so says the man.
He has a guy who works for him with a Chrysler mini van who changes his trans fluid every 3k and the car has 165,000 on the orginal trans. He said on average thay go maybe 90k.
Why don't they tell ya this **** up front?
It like $89.95 to change trans fluid, as opposed to $2,800 for a rebuilt auto.
Maintenace its all about maintaing the stupid car.
He said in the 24 years he's had the trans shop hes never had a trans of his fail.
I thought the dam things went 100k to 125k and just burned out.
Not so says the man.
He has a guy who works for him with a Chrysler mini van who changes his trans fluid every 3k and the car has 165,000 on the orginal trans. He said on average thay go maybe 90k.
Why don't they tell ya this **** up front?
It like $89.95 to change trans fluid, as opposed to $2,800 for a rebuilt auto.
Maintenace its all about maintaing the stupid car.
Thread Starter
Instructor
Joined: May 2007
Posts: 177
Likes: 0
From: Spring TX
Thanks!
A huge thanks to everyone who took the time to respond to this thread. I'm not much of a mechanic myself; although I have done some minimal work on my cars back when I was just out of college, broke, and had no choice. Having the Vette really makes me feel especially mechanically un-worthy, so all of your advice was greatly appreciated.
After reading through the thread I went and checked the car. The current alternator is an AC Delco unit; so there's a chance it could still be under warranty. Keep hope alive, eh?
After reading through the thread I went and checked the car. The current alternator is an AC Delco unit; so there's a chance it could still be under warranty. Keep hope alive, eh?
Burning Brakes
Joined: Oct 2006
Posts: 778
Likes: 0
From: Fort Worth Texas
I will not let a mechanic touch any of my vehicles unless absolutely necessary. With that said........even with little ability and a few simple tools, you should be able to pop the alternator out pretty quick. While I am not a mechanic, I do enjoy working on my vehicles when needed.
A few days a go I went over to my parents house and changed my mothers starter in her van in 12 minutes (was in a HUGE hurry) with a socket wrench and 3 sockets. Later that afternoon I replaced the alternator in my '86 vette. I needed to get it done and a storm was coming in. Snatched the socket set and the alternator out of the back of my van, popped the hood on the vette, looked at my watch and raced the storm coming in. My neighbor stood on the other side of the engine watching me and giggled most of the time.
10 minutes later with a newly installed alternator( a record for me
) I closed the hood just as the first drop of rain hit. Yanked the cover on and ran into the house as the bottom dropped out.
In other words.......it is not that hard of a job to do and on a nice sunny day you can relax, get the job done and enjoy some personal time with the vette outside of the drivers seat.
A few days a go I went over to my parents house and changed my mothers starter in her van in 12 minutes (was in a HUGE hurry) with a socket wrench and 3 sockets. Later that afternoon I replaced the alternator in my '86 vette. I needed to get it done and a storm was coming in. Snatched the socket set and the alternator out of the back of my van, popped the hood on the vette, looked at my watch and raced the storm coming in. My neighbor stood on the other side of the engine watching me and giggled most of the time.
10 minutes later with a newly installed alternator( a record for me
) I closed the hood just as the first drop of rain hit. Yanked the cover on and ran into the house as the bottom dropped out.In other words.......it is not that hard of a job to do and on a nice sunny day you can relax, get the job done and enjoy some personal time with the vette outside of the drivers seat.