HISTORY-In 2005 the alternator went on the car. At that time the car had roughly 76000 miles on it, so that was fare. I didnt expect it to last forever. So I paid in the area of $100 to get it rebuilt. Moving on to 2006, the alternator went again, this time the mileage was roughly 80000 miles. The place that rebuilt it mentioned that the "regulator" went on it. Due to this I got a new battery as well.

Fast forward to two days ago. Driving the 88 during the day, and I noticed the battery light was illuminated, and from past experience I know what this means. Flipped to the volts setting immediately, and it read 11.5 volts(car is usually 13.5 volts or so). Drove the car home immediately. Mileage on car 81000 miles now.

This morning I yanked out the battery, and took it to the same place. Just picked up the alternator again and they told me that the exact same thing happened, and that was the regulator went again. They also mentioned that my battery wasnt great, but I think they wanted to sell me a new battey. Battery was in the 13.0 volts range when they were testing it.

Any idea why I keep on blowing the regulator in the alternator? It's becoming a real pain in my butt. Thats 3 alternators in 5000 miles. **** me off!

Anyone have this problem? Is there something in the car drawing power? How do I test to see what my problem is?

Thanks.

 

Soon as my alt went I replaced it with a rebuilt from the local AC Delco store and have had no further problem, though I later had to replace the battery as a matter of time.

A bad battery could cause excessive charging and ruin an alt though, if you are not seeing excessive charging on the digital I doubt that is the problem.

I wonder if something in the alt is causing the regulator to go out??

I should think that the charging system could be tested to see if the alt is being called upon to supply current above its rated capacity.

 

This is a common problem on the earlier C4s - eating alternators. I believe I just saw an article in one of the mags about it too. I didn't have a chance to read it but I suspect it'll have tips and clues.

Actually I believe there are two factors at work here.

First is the actual design of the alternator and

Second is where the alternator is mounted.

Later design alternators, like the one on my 96, are of a different design both externally and internally. They are far less prone to failure because of the design changes.

Also, the alternator is mounted differently, that is, in a different location, much higher and much more in board. This moves the alternator farther away from the heat of the driver's side exhaust manifold. Heat's helping to kill 'em.

This same heat problem effects the plastic power brake booster. Some have gone to a metal booster to solve that issue, while others have fabricated a heat shield mounted between the booster and the exhaust manifold. I've even seen that done in one of the mags that was doing a L98 build up.

So, in the case of my 86, which had the same alternator failure when I was 1,000 miles from home, I've taken to carrying another NEW alternator in the hatch and the tools to swap it out should the need arise.

I suggest you fabricate a heat shield to help keep excessive exhaust heat off the alternator. Cheapest way I know of to address the problem. Of course, carrying a second alternator is a good idea too because you never know . . .

Jake

 

Isn't a more obvious answer that the shop did a lousy job rebuilding and that they haven't gotten better.

It's like the guy who got a vasectomy only to soon impregnate his wife. So he goes back to the doctor and makes him do the surgery a second time. Same result and now he has two new kids to feed. Maybe it's time to try someone else?

 

I thought that, but I was hoping that wasnt the issue, or maybe I should hope that indeed that is the problem.

 

They should have rebuilt the second time at no charge. I just installed a NEW alternator from Motor City Reman I paid $69.00 plus shipping. It has a lifetime guarantee. My original alternator is still good and I am keeping it as a backup.
I changed as preventive maintainance and to install a Power and Amp pulley set and new belt.
I have heard this about Corvettes "eating" alternators. Not sure I believe that. I do believe there are some crappy parts out there.

 

This has come up before and I'm sure there are those who are driving 20year old cars with the original alternator.

My point is that they fail often enough in early C4s that there's a valid concern. My Vette's a daily driver; I've criss-crossed the country more than a few times, sits idling in stop and go traffic and is on the road all year round (not what's referred to as a "garage queen"). I even drove it all this past winter in Chicago's cold and snow. So my alternator use and exposure is more than many experience.

It's sort of like the headlight motor issue on the early C4 which resulted in GM changing the design, but, hey, if a guy only/mainly drives during the daylight hours, his headlight motor may last much longer.

I hope someone has the mag that has the article about "eating" and posts on it so we can all get the straight skinny from the author's research.

Jake

 

There are a couple of things that lead to these problems, 1. The ground connections from the batery to the engine block need to be checked for a good connection and can have corrosion on them, the cables can be old and cause problems where the terminals are terminated on the ends. Check and replace as needed. Older C-4 suffer from battery discharge issues due to the above problems. The alternator tries to charge up the battery and due to dirty defective connections it creates heat at these points. Please check your cables and where they are connected and make sure those connections are not bad or dirty. Good luck

 

Also make sure both halves of the alternator case are grounded together( pulley side of case, stator in the middle and back side of case all have to have good contact to ground). Otherwise the internal regulator wont work properly, giving you a less than adequate charge of the battery.

 

Those are DEFINIELY GOOD POINTS and should be addressed.

In my case, and remember I'm speaking of MY experience, (knowing how a good, clean ground connection is) after building my 415 I took a wire brush and cleaned not only the bolt, but the cable ends AND the hole the bolt screwed into on the block, to insure a clean ground.

I even pulled back the covering to SEE that the cables were not corroded inside. Still, the alternator failed. Okay, now I'm going see posts "Well, the alternator is at fault" or words to that effect, but it ain't so!!

COME ON GUYS, It' a design issue; just like so many precending it.

Either do as I have done or be prepared to suffer the same fate as I, and the original poster have experienced.

Anyone can dance around this issue as long as they like, but I've identified the cause and the cure.

Do what you want; it's not my car, it's yours.

Jake

 

Now, I'm waiting for someone to chime in with:

"Buy a - fill in the blank as well as a price which will be WELL over $200 - and you problem will be solved", which is nothing more than the manufacturer's way of keeping his hand in your pocket.

Remember, they never tell you that THEIR PART IS GOING TO FAIL, they only tell you that their part is "The best thing since bubble-gum".

BE SMART!

Jake

 

Most rebuilds get fixed what only went bad,then you dont even know what the rebuilder is using,if hes using the cheapest chit he can get and charge premium for it.

If the same part they replaced fails,its a good bet the replacement parts are simply cheap inferior quality..especially after a few times!

Im also urge most L98 C4 owners,if they want peace of mind,to do the CS144 upgrade found on later models.Its way better in design.

Sure some people with the older units got some life out of theirs...it happens,but the rebuild/replacement and majority of failure in replacement parts have been very high.

Myself included..the Vette was the ONLY car I had constant alternator failures with,and I did replace the battery and made sure the charge was healthy and excellent before doing a new one.

 

I own an 87 vette and drive it everyday, it has 215k miles and I have replaced the alternator 3 times. I always buy AC Delco rebuilts and the last one is more than 6 years old. I believe that OEM early C4 alternators have inadequite cooling and is the cause for their shorter life. I think it is obvious that the replacement voltage regulator your rebuilder is using isn't adequite and I would recommend another rebuilder with a better reputation. The search function will get you to a number of posts where members have found replacement alternators that have higher amp capacity and better cooling and last for a longer time. Advance Auto sells rebuilt AC Delco C4 alternators that have a lifetime warranty, but I think you would be more comfortable with a more reliable alternator given your experience.

 

I have the same problem. I've got an 85.

I had the alternator rebuilt the first time and it died shortly after (1000km). I brought it to another place and had it rebuilt again. It then died again two more times but they rebuilt it for free. They said the regulator was burnt both times. After 4 rebuilds it seems to have diminished the amount of usable time and it now only lasts 300-400km if I put my battery tender on it every other time I drive it.

I am now at the point where I have just replaced the positive and negitive battery cables and ensured that all connections are completely clean. This did nothing for my particular situation but eliminate another possibility.

It seems that it tends to die sooner when I drive it hard. I have an MSD 6AL so maybe it strains an impared system alittle faster???

I like the response earlier in the thread that the two halves may not be grounded to each other enough. It makes sense.

I will dissassemble the alternator and clean the mating surfaces and contact points and let you know what happens.

 

ONE very important issue that no one here has yet observed. Those cars that are driven daily, seem to fewer electrical problems and work just fine. That is to say, very few battery or alternator problems. Those cars that are driven on weekends, appear to have battery problems once a year with corresponding alternator failures.

The common thread to most of these problems is the state of charge on the battery as the car sits between drives. So here is the answer; buy a battery tender! And keep the battery plugged in when ever your not driving. The battery will be charged and ready for the next weekend drive. And the alternator will not be laboring/overheating trying to charge a half dead battery.

At a cost of $35 bucks its cheaper than an alternator and battery every year.

 

The problem is a bad design which cannot take heat. And its hot in there. A weak battery doesn't help like JrRifleCoach said. My recommendation is: replace the alt with a better design and replace your battery at the same time.

Note: more amps doesn't mean its better, it just means it has bigger output and generates more alt killing heat.

Note2: the Iceberg mod they sell for CS130 should be better. Mine lasted 3 months so don't waste your money on that either

Here is my tech tip about solving the problem after losing 4 or 5 CS130 alternators in 2 years. Since then with the same alt with no further problems.

Link updated

Addition to the tech tip: bad ground connection also heats the alt. So, I installed a extra ground lead from the alt casing to the exhaust manifold just to be sure.

 

Wow, I hope I don't have your luck with this,,, my CS120 I bought NEW in 1997 is still going strong.

I have put 40K miles on this alternator and for the past 15k miles it has resided above my hooker headers.

Also I have a 300 watt and a 200 watt stereo amp in my car.

 

I had the same issues on my 87 , three alternators in a row. In these cases they where all rebuilds so in the long run it cost more than they are worth. When it comes to alternators for these cars its better to go with
a quality new one that has a warranty less headaches thats my 2cents.

 

Whats this CS144 upgrade? It just bolts in?

 

I did the cs -144 conversion 2 years ago and no more problems. The mounting ear on top is a little thicker so you have to grind off a little on the alternator ear or on the brakcet. That's it, the wiring harness is the same. A cs-144 is a monster compared to the original but there is plenty of room for it.