2005 C6 (110,000 miles)

This summer I notice upon starting the car in morning that the battery indicator show my car voltage around 12.5 voltage and I my dash display indicator charger malfunction. I then apply gas to raise the rpm pass 1000 and the problem indicator goes away and the voltage ramps up to around 14 voltage like normal.

It this a normal thing or is my alternator starting to go bad and this is my hint.

 

Assuming that you have checked your belts, and they are OK, then your symptoms could be caused by worn carbon brushes, a bad diode, or a faulty voltage regulator, all found inside the alternator.
Get a check done on your charging system, and that will tell you what is causing the problem.

Good luck

 

 

Verdict is in....Need a new alternator.

Should I go with (110 amps) OEM unit or upgrade to an aftermarket with higher current output (140 amps, 145 amps, 170 amps.)

 

I love my 170A unit. Always stays at 14.6 V even at idle.

 

Related Alternator Story:

I had my alternator die 3 weeks back at an autocross event. All this happened out on an airport runway on a hot Saturday afternoon. We (my son and I) ignored the intermittent "Service Charging System" warnings in the DIC for a few runs....then it all went south while my son was driving a hot lap. Apparently anti-lock brakes and power steering systems need power, so he did a nice job of flat spotting the front tires when the car didn't want to turn so easily and he thought he was heading for the weeds.

I thought the weekend was done for us and a flat bed tow to the dealership was our only option.

I knew one of the guys I hang out with was a Porsche mechanic by trade, so I asked if he'd take a look at it. He diagnosed the problem as the alternator, but made me call Auto Club to send a guy out with a tester to confirm. Once confirmed I started to call the dealer and the tow.....meanwhile this guy jumped on his phone and called the local Pep Boys. He found the part a few blocks away and said "I've got them holding it at the parts counter. Pick up that and a 15mm wrench. I'll help you". To make a long story short, this guy swaps in the new alternator in about 5 minutes with a screwdriver (for the air intake clamp) and one wrench. We jump the car, and 0 problems since.

And best of all we didn't miss our race for championship points the next day!

He wouldn't take any payment or anything. All he asked for was a promise to pay it forward (believe me I will). The part and the wrench cost like $200. I can't imagine what a flogging I would have received from the dealer doing the job.

Autocrossers are the best!

Anyway, I just thought someone might appreciate a related story. It doesn't answer your question, but for what it's worth, the Pep Boys unit seems to work just fine.

Obligatory flat spot photo:

 

How far did he slide? Must've been a ways. Looks like that tire was worn out anyway.

 

Great story.

 

Don't want to hijack Reggied's thread (I tuned in to hear the answer on the amperage myself).

But to answer your question:
Tires were my old practice/DD tires and had about 250 autocross laps on them already, so their racing days were over. He was probably doing about 60 into a decreasing radius sweeper....he said steering suddenly became really stiff and he was heading off course, so he just dumped the anchor to be safe. We pushed the car back into the paddock, so we didn't know about the flat spotting issue till we had the alternator fixed and were driving out of the event. Thump, thump, thump, thump! We're were like "Ah, what now?"

And to quit hijacking the alternator thread, link to photos of my kid and I autocrossing the car (to complete the story):

https://www.corvetteforum.com/forums...post1589944260

 

My opinion , the stock OEM one is under-rated. However if it is worth upgrading depends on a few things:

1. Most importantly, do you have time to order and have a billet tech shipped to you and install it. ie. you have other transportation or do you need it fix asap. Fastest would be an auto store replacement obviously.

2. Is you car bone stock or modded or plan to be modded. Stereo upgrade, etc.

3. How much longer you plan to keep the car.

 

The billet tech seems to make the car run much smoother. Is it just the placebo effect? I don't know but it just seems better. With all the finicky electronics in our cars having a better more stable voltage supply can't hurt.

I would go this route again without a doubt.

 

That drop in voltage thing just happened to me. It was the battery cables. the negative clamp tensioner just broke. Cables come as a set.

 

Bushes are worn out, and just a matter of how deep the slip rings are worn down/grooved as well.

Bushes cost around $7 to replace if they are just the problem, and entire alternator can be rebuild for $30 in parts if needed (new slip ring and bearings as well as brushes).

But that fact that you asked the question to begin with (don't know how to service an alternator), may as well just pay the corvette tax and pick up a new alternator instead.

https://www.corvetteforum.com/forums...nator-fix.html

 

It would also be the route I would go, if/when I have a problem, however the vette is not my only car, so I could afford to wait to get parts.

 

My 08 with 68000 miles OEM Alt.& it stays at 14.5/14.7 at idle (Day Time) at idle or 3000 rpm makes no different with a Alt.....

 

Ugh!....I'd like to rescind my previous comment. The Pep Boys unit lasted about 4 weeks. It gave up the ghost Sunday during an autocross competition causing my son to miss his competition laps.

Again, not to hijack Reggied's thread, but I enjoy the "stories" here on the forum, so I share them (although this story ends exactly where Reggied's thread starts):

Busy Sunday at the CSCC autocross event at El Toro this weekend. We only get 3 competition runs this weekend (we had plenty of practice runs on Saturday). My son and I pull in the multi driver line as usual, and I took my 3 runs first...the replacement alternator had been running fine, so it wasn't on our minds.

My laps go OK. Hit a cone on first lap, 2nd was clean and decent time, but by lap 3 the back tires are getting way too hot, so I spin on the last lap (3 times actually! ). I'm done, and I've got one time in the books to sit on. I jump out of the car and attack the back tires with our water sprayer so they'll be cooled down and back in shape for my son's laps (we're basically each other's pit crew ) and jump around the car adjusting tire pressures so he has a good car to race.

As the line starts to move, I hear "Dad, we've got a problem"....I peek up from the passenger front tire (I'm adjusting air pressure there). Matt (my son) is pointing at the DIC with a look of concern on his face. SERVICE CHARGING SYSTEM....Ugh!....not again! He's sitting 3rd place in the points, so we don't want him DNS for the event. So, I tell him, go take a lap...we'll deal with it after...."you need to at least get on the board for the points!".

Now he's a good kid, and he was driving the car last time it died in the middle of a hot lap....so he was very concerned to say the least. He was more than happy to pull the car out of line, but I wouldn't let him and sent him to the line (I know, I know...probably shouldn't be stupid, but voltage was just about 11 and we came to race, and he's been competing all season...at least he knows what the car will do if it stops running and can take it easy and not flat spot the tires again).

Of course being a kid in a Vette, he's always getting lectured from the adults. As he pulls to the start line the starter notices his look of concern and the lecture starts...."hey don't look so scared....just take it easy out there!" He's been autocrossing the Vette since the weekend after he got his learner's permit. And while it's only been a year, he's caught me so he's certainly not scared of pushing the car. I did laugh a bit as I saw him "enduring" the lecture while trying to get focused for his lap.

Well, sorry to say, his lap was a bust and he limped it straight back to the paddock. At least he got a time on the board.

So to make a long story short, for the second time alternator failure cut our day short:




So back on the thread topic:

Pep Boys happily replaced the defective unit (and they all have a lifetime warranty)....but that being said, the new one seems to exhibit the same symptoms as the OP in this thread. Low voltage at idle (especially with AC on, like 12.3-12.5)....comes up fine while driving (14ish). I'm also noticing a high pitched whine with the new unit. That's could be a deal breaker for me...can't have jet engine noises ruining the symphony of the LS3 song I love so much! I'm giving this replacement a day (just to see if it's a battery charging issue with the voltage, and potentially just a break in issue with the whine). I'll report back.

But, for now, please rescind my previous comment until further notice!

 

Downside of the valeo alternator, they do not like to be over rev'd!!!!!

It breaks the coils winding wrap plate, and this causes the wires to crack.

So when fully rebuilding the units, you have to check the coil winds for any movement or not to being with (coil movement and the unit is not rebuildable).

skip to 12:45,

 

did you say that the alternator can be changed in five minutes?

 

is this a rebuilt item or newly mfg'd?

 

I doubt it could be done in 5 min, but it is a easy job. Hardest part is getting the belt back on. Just a few bolts and a few wires ( one bolted on and one with a connector).

I went through 4 rebuilt Alts on the 85 before I got a good one. That is why I bought a new one for the 07.