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Alternator replacement problems.

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Old Dec 10, 2013 | 12:42 PM
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Default Alternator replacement problems.

Has anyone had a problem replacing the alternator on a 2003?
Here is my problem. The alternator clutch is making noise and will probably fail in the future so I decided to replace the whole alternator being that the car is 10 years old. So, I have installed three different alternators (remanufactured, from three different sources) to date and all three will not charge. I took the second one to Autozone to be tested, even though I didn't get it from them, and it showed bad. Now I got one from Autozone and it does the same thing, Charging System Fault, and the amp gauge is showing around 9 to 10 volts. Checked the output with a meter to be sure it was correct. BUT, when I put the old alternator back on everything works just fine, other than the clutch pulley that is going bad. So has anyone had this problem? Is there a first and second generatoin alternator and I keep getting the wrong one. Do remanufactured alterantors just not work on C5's. I'm stumped...........
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Old Dec 10, 2013 | 01:04 PM
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I had a very similar experience. I tried 5 new AC delco units and none would work. We finally installed one off of a 99 vette and were shocked to find it worked and is still working perfect. Can't tell you why.

The odd thing is that we talked the owner of the 99 into letting me have his old alternator in exchange for my new one which works fine in his car but not mine. ???
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Old Dec 10, 2013 | 02:02 PM
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Originally Posted by radvetter
Has anyone had a problem replacing the alternator on a 2003?
Here is my problem. The alternator clutch is making noise and will probably fail in the future so I decided to replace the whole alternator being that the car is 10 years old. So, I have installed three different alternators (remanufactured, from three different sources) to date and all three will not charge. I took the second one to Autozone to be tested, even though I didn't get it from them, and it showed bad. Now I got one from Autozone and it does the same thing, Charging System Fault, and the amp gauge is showing around 9 to 10 volts. Checked the output with a meter to be sure it was correct. BUT, when I put the old alternator back on everything works just fine, other than the clutch pulley that is going bad. So has anyone had this problem? Is there a first and second generatoin alternator and I keep getting the wrong one. Do remanufactured alterantors just not work on C5's. I'm stumped...........
This is a fairly common problem. C5 can be very picky about alternators. You may have to have someone run your vin number to get the correct one. Best bet is to have the one you got rebuilt or you may get lucky and find a reman that works.
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Old Dec 10, 2013 | 03:36 PM
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Originally Posted by Bill McCassey
I had a very similar experience. I tried 5 new AC delco units and none would work. We finally installed one off of a 99 vette and were shocked to find it worked and is still working perfect. Can't tell you why.

The odd thing is that we talked the owner of the 99 into letting me have his old alternator in exchange for my new one which works fine in his car but not mine. ???
Wow, I wonder how many alternators any of the local suppliers will let me go through to find a good one? Probably not many. I've changed alternators on most all the cars I've owned for years and have never encountered such a quirky problem. Glad I'm not the only one.
Thanks.
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Old Dec 10, 2013 | 03:41 PM
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Get a MANTECH replacement.

Rebuilt alternators are not rebuilt very well these days unless you have a real shop do it.
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Old Dec 10, 2013 | 03:48 PM
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Originally Posted by BigGun
This is a fairly common problem. C5 can be very picky about alternators. You may have to have someone run your vin number to get the correct one. Best bet is to have the one you got rebuilt or you may get lucky and find a reman that works.
Yep, thanks. Rebuilding my original is what I've been thinking lately. I believe that may be the best way to go at this point. And like I was saying, the alternator is actually still working fine. I may just replace the dieing clutch pulley for now. Or not, while I have it back off I may as well have it rebuilt.
Thanks for the input.....
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Old Dec 10, 2013 | 05:43 PM
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haven't seen a delco c5 alt but have for a jeep and a ford truck. they aren't remans they are new china castings and windings. they seem to work well enough but they aren't rebuilds
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Old Dec 10, 2013 | 06:16 PM
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Very common problem. I experienced the same exact thing with a 2001 and 4 NEW alternators. Took my chances and ordered a custom built unit and all is well.

Good Luck!
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Old Dec 10, 2013 | 06:28 PM
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Originally Posted by radvetter
Has anyone had a problem replacing the alternator on a 2003?
Here is my problem. The alternator clutch is making noise and will probably fail in the future so I decided to replace the whole alternator being that the car is 10 years old. So, I have installed three different alternators (remanufactured, from three different sources) to date and all three will not charge. I took the second one to Autozone to be tested, even though I didn't get it from them, and it showed bad. Now I got one from Autozone and it does the same thing, Charging System Fault, and the amp gauge is showing around 9 to 10 volts. Checked the output with a meter to be sure it was correct. BUT, when I put the old alternator back on everything works just fine, other than the clutch pulley that is going bad. So has anyone had this problem? Is there a first and second generatoin alternator and I keep getting the wrong one. Do remanufactured alterantors just not work on C5's. I'm stumped...........
What is the OE part number on the label of your old one?

Another option, to save on $, just take the old unit to an alternator repair/rebuild shop and have them remove and replace the decoupler hub.
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Old Dec 11, 2013 | 09:42 AM
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Originally Posted by racebum
haven't seen a delco c5 alt but have for a jeep and a ford truck. they aren't remans they are new china castings and windings. they seem to work well enough but they aren't rebuilds
The last one I got, did indeed have a made in China sticker on it. It is supposed to be a reman but it looks like new. It is actually the best looking one of the three that I have gotten.
I think I'm going to do what a couple of you guys have suggested and just have mine rebuilt. The place where I bought the first two thought I was crazy saying that neither one of theirs worked. Now I have to take this one back to Autozone and see what they have to say. I bought it on-line so I'm going to find out if they will take it back at the local store.
I really appreciate the feedback and I'm glad I'm not the only one who has experienced this.
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Old Dec 11, 2013 | 10:44 AM
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Originally Posted by racebum
haven't seen a delco c5 alt but have for a jeep and a ford truck. they aren't remans they are new china castings and windings. they seem to work well enough but they aren't rebuilds

My suplier thinks they have or can get some. ?


ACDELCO GM ORIGINAL EQUIPMENT

10316182 Alternator/Generator
1 03-03
110 AMP GEN(K63); OEM P/ N 10316182 OR 10246634; 2ND DES SEE 10353440;

10353440 Alternator/Generator 691.76 365.42 0.00
1 03-03
Alternator OEM P/ N 10355775, 10305776, 10350160, 10350161
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Old Dec 11, 2013 | 11:06 AM
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Originally Posted by radvetter
Wow, I wonder how many alternators any of the local suppliers will let me go through to find a good one? Probably not many. I've changed alternators on most all the cars I've owned for years and have never encountered such a quirky problem. Glad I'm not the only one.
Thanks.

I even sent my old/bad one to advanced. They tested it and said it was fine but I noticed (on the test sheet) that they don't test L terminal.
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Old Dec 11, 2013 | 11:12 AM
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The alternator also has an interface with the PCM that a lot of rebuilders can not test or fix if there is a problem. I bought 2 NOS Valeo spare alternators for my car as part of my inventory. Even they may not work if or when they might be needed due to the C5 being so fickle.
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Old Dec 11, 2013 | 02:15 PM
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Originally Posted by radvetter
The last one I got, did indeed have a made in China sticker on it. It is supposed to be a reman but it looks like new. It is actually the best looking one of the three that I have gotten.
I think I'm going to do what a couple of you guys have suggested and just have mine rebuilt. The place where I bought the first two thought I was crazy saying that neither one of theirs worked. Now I have to take this one back to Autozone and see what they have to say. I bought it on-line so I'm going to find out if they will take it back at the local store.
I really appreciate the feedback and I'm glad I'm not the only one who has experienced this.
as easy as they are to install you could always test it first and see if it works

that made in china sticker was present on the one i just put in my ford as well. has a lot of output though. maintains 14.4v at idle with the lights, heater and stereo on with no problem
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Old Dec 16, 2013 | 08:10 AM
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Originally Posted by LoneStarFRC
What is the OE part number on the label of your old one?

Another option, to save on $, just take the old unit to an alternator repair/rebuild shop and have them remove and replace the decoupler hub.
Sorry, been out of town for a few days.
The OE GM P/N is 10305775.
I had them cross the number at Autozone after the last one didn't work and they said that by this number they gave me the right one. Rebuilding the original one is what I've decide to do. I'd hate to keep trying more remaned units. Some of these parts suppliers give me funny look when I say it just won't work on my car and then I have to explain the problem. It's been kind of a funny experience.:crazy
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Old Dec 16, 2013 | 12:06 PM
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I've posted about this issue over 100 times on this forum over the last 12 years.
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Old Dec 16, 2013 | 08:58 PM
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Originally Posted by Bill McCassey
My suplier thinks they have or can get some. ?


ACDELCO GM ORIGINAL EQUIPMENT


10353440 Alternator/Generator 691.76 365.42 0.00
1 03-03
Alternator OEM P/ N 10355775, 10305776, 10350160, 10350161

GM (and AC Delco) part # that supersedes the OE number is 10353440.

Rock Auto sells the NEW ACD unit for $320.99 and with their discount code (I can give you) $304.94
Amazon shows same unit at $263.xx

OP: Considering the amount of time/money you've wasted on this matter so far, I would recommend using one of the two above quoted sources and have an all new unit. There are other sources for the same part number, but these two are two of the best prices I found.
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Old Dec 17, 2013 | 01:04 AM
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I had the problem also.
Finally someone told me that the replacement had to have some computer chip inside it so that it could talk to the cars computer, then the computer would tell it to charge.
I ended up getting mine rebuilt by a local shop. It was cheaper than a rebuilt replacement
I am thinking it cost around $60
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Old Dec 18, 2013 | 04:36 PM
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Originally Posted by Jeffwilson34
I had the problem also.
Finally someone told me that the replacement had to have some computer chip inside it so that it could talk to the cars computer, then the computer would tell it to charge.
I ended up getting mine rebuilt by a local shop. It was cheaper than a rebuilt replacement
I am thinking it cost around $60
This is what I suggest for those with issue with their factory alternator.
You just cant cross reference an alternator that fits the bracket and has the correct connections. It has to communicate with the PCM via the L terminal.
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Old Dec 19, 2013 | 09:15 AM
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Here is the design interface we have discussed:

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