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Here's one of those "extra credit" questions for any C6 alternator specialists here on CF. I've just received a supposedly new GM replacement alternator for my Red from "Amazon.com LLC". It's obviously a take-off (at best) with a broken plastic connector. The black-on-silver label reads:
GM GM P/N 25888970......................Valeo
.........14 V 145 A............2605916 A
.........670304084011......TG15C139 Made in Mexico
<long bar code>
........NCD9632FJ8R7
It's my understanding that Valeo is a remanufacturer of GM alternators. Did I pay full price for a new alternator but got a rebuilt?
Last edited by Eritosthenes; Nov 21, 2017 at 09:09 AM.
Valeo also manufactures new parts. You can get more details by going to the following link and searching your vehicle. Select the 'Show Item Details' tab and it will show the specs and a part number cross reference. There are good details for this part on the Rock Auto web page as well.
Valeo is who made the unit to begin with, as as you figured out, was made in mexico new as well.
Now that out of the way,
What the company that re manufactured the alternator did since it came with a broken back cover (was not Valeo), was to just pull the voltage regulator, did a quick bench test to make sure it was fine and replaced the brushes in the bush housing, and if if needed and the slip ring was way worn down, may have replaced the slip ring too.
Hence all of the stuff you could have done on the old unit for about $25 max in parts if needed to rebuild it yourself.
Note, most of the time, you don't need new parts, but instead just clean the contact point on it alone. https://www.corvetteforum.com/forums...nator-fix.html
Also to point out, most of the time someone think that its the alternator the problem, is not, but instead a terminal down on the starter solenoid where the alternator main charging wire, and the battery main charging wire are bolted tighter, with either a loose nut, or the terminal itself cracking away from the main body of the solenoid.
Note if you look just above the starter, can see where the negative battery cable is bolted to the engine block, so when checking/cleaning the starter solenoid bolts and terminal to make sure they are fine, you want to check the ground bolt for the negative cable to make sure it clean and tight as well.
So here if the starter solenoid is the problem with the terminal cracking away, only the $24 solenoid itself needs to be replace on the starter motor.
Lastly, if you are not running the OEM spark plugs, and OEM spark plug wires, these too can cause problems with the perfectly working OEM alternator not putting out enough voltage as well. The after market plugs and wires do not have the needed resistance values to supress RF feed back to the coils. So with the spark RF noise back into the system through the coils, it causes problems with the ECM not controlling the alternator correctly, but instead to put out less than its normal 14.7 voltage output instead.
Hence have seen RF noise from after market plugs and wires back through the coils to cause the ECM to clip the alternator output way down into the 13 volt range instead.
Alternator label question
