SaabCentral Forums banner
1 - 11 of 11 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
I have a 2001 9-5 SE, with v6. The alternator tested bad in the car. I replaced the diodes. It charged fine. The next day it quit again. I put in a new alternator. It charged fine. The next day it quit again. My question: Is there anything that can cause the alternator to go bad like that? Probably killing the diodes. The only thing electrically hooked to the alternator is the starter, the battery and the exciter circuit.
 

·
Registered
Joined
·
1,958 Posts
Oh man do I know your pain. I've had to replace the alternators in both my cars. Why they fail, I'm not certain. I think in my case it was related to continued driving with a dead battery cell (Battery was slightly discharged on a road trip, but I drove it home over 300miles) And on my '01 jump starting a car while my engine was running, which apparently you're not supposed to do.

On both cars I noticed the 13mm nut on the B+ terminal of the alternator wasn't very tight. And the screws holding the voltage regulator to the alternator were not very tight. (Finger tight at most) Check your voltage regulator screws if you haven't already. If your B+ cable from the alternator to the battery is excessively corroded, this will definitely cause a charging issue. How this is possible, I don't know, the cables seem to be VERY well insulated and sealed.

Long story:
My '03 failed last summer. It took 3 different alternators, and finally a new battery to resolve the problem. The car was on jack stands for almost a month. I had to wait for shipping. :roll: 2 remanufactured alternators from OReilly auto parts were junk. The rebuild quality was literally junk. Drippy soldering, and some barely soldered spots. I finally ordered a Bosch ReMan from eEuroparts, installed it. On that Bosch unit there was a huge warning label on the B+ terminal of the alt. It read DO NOT install this alternator with a weak battery, Damage will certainly occur. How ridiculous I thought, since alternators are supposed to recharge batteries. But, I took out my battery, which was the original, took it to AutoZone to have them charge it for me. They informed me my battery was bad, it had a dead cell. This explained why I thought it was simply discharged from the cooling fan running after shut off. So I bought a new battery, installed it and I've been fine since.

Now, on the '01, I gave a jump to a stranger one evening. I left my engine running while the stranger started his dead car. I Drove home, all seemed normal. A few days later I drove the car again, 6 miles to work. Everything seemed normal. 9 hours later, I go to my car to go home. No power at all. A completely dead battery. After several failed attempts to jump start my car, I took the dead battery out, installed a new one, and drove home. Everything seemed fine. That evening I drove the car a mile to return a DVD. I barely made it home. Dead alternator. It was actually causing a drain on the battery. :eek: Another Bosch ReMan from eEuroparts, recharged the battery, and no problems.

From what I can figure, these 130amp alternators can not tolerate a dead battery cell, or jump starting another car if the engine is running. It must short the alternator out. BMW, Audi and newer Volvos apparently have the same delicate Bosch alternator issue.


I created a write up on how to remove and replace the alternator in the V6, since I've done it so many times. :confused:




:x
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #3 ·
Thanks for the info Nathan. I have been using 2 new batteries alternately to keep the car running while waiting for the alternators.
I meant to say on the first one that I replaced the regulator not the diodes, but I think they are the same package.
I will take the batteries to be tested but I have kept them charged on the big charger and they are new so I don't really suspect them.
I have changed the alternator in and out 5 times now so have gotten pretty good at it. Can change one now in about 2 hours. Do you take it out the top or the bottom? I do the top.
Still working on it.
 

·
Registered
Joined
·
1,958 Posts
If you've replaced the Voltage regulator it HAS to be the rectifier plate.

But, it could also be a burnt out bulb, or a broken wire. Yep. I read something in the WIS (Workshop Information System) If your charge indicator bulb on your cluster is burnt out, your charging system wont operate properly. And if there's a break in the tiny wire going to the alternator, it won't charge properly. Does your charge light come on when you turn the ignition on, and go out after the car is started? If so, then obviously the bulb is good, and that thin wire going to the alt. is also good.

If you decide on getting a rebuilt unit, really beware of poor quality. When I got the 2nd rebuild from OReilly auto, before I left the store I took the air snorkel cover off, and saw another sloppy soldering job connecting the stator coil to the rectifier. The Bosch units use welds. And then I took the voltage regulator off. The brushes were so worn out I couldn't believe it. I returned it before I left, and ordered the Bosch unit from eEuro. What a difference in quality, no difference in price, it arrived in 3 days, comes with a 2 year roadside assistance package, and it's an original Bosch.

I removed the alternator out from the top. Removing drive axles, front control arms, etc. is just too much work. And I don't like having to replace the axle to transmission seals if I don't have to.

Here's my write up.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
Great write up!! That is almost step for step the way I took mine out. Had to do a little jacking up and down of the engine at different points in the process of getting it out.
What ever my problem is, it is not in the alternator. My first one went bad, didn't charge any more. I took it out and had it tested and it was bad. I got the regulator out of another one I had and put it into this alternator. I took it to be tested and it passed all tests. I installed it and measured the voltage at the battery with the car running and it was nearly 14 volts so I know it was charging. The next day it quit charging. The battery at each step was new and fully charged. I pulled it out again and took it to be tested. It failed the test.
I got a used one from another car I have and put it in. It charged for about 20 minutes right at 14 volts. Then it failed. I pulled it out and took it to be tested. It failed the test.
I ordered a new one, Beck Arnley, and put it in. I checked the voltage at the battery again with the car running and it was a little over 14 volts. So, again it was charging. The next day it had quit again. I pulled it out and took it to be tested. It failed the test.
I got another new one. I took it to be tested before I put it in the car. Passed all tests. I put it in and measured the voltage. Just over 14 volts. It was charging. The next day it quit. I pulled it out and took it to be tested. It failed the test.
So there have been too many alternators in there for it to be an alternator problem. All the lights on the dash work properly. I've done a continuity test on all the parts of that circuit that send a voltage to the wire with the 8mm nut on it. Interestingly the WIS says that that wire should get +15 volts on it. When it is disconnected from the alternator it has apprximately battery voltage on it with the key on. When it is connected to the alternator it has about .5 volts with the key off and about 1.75 volts with the key on. I thought that was a little strange so I checked a different car and it's voltage at that point checked the same. And that car works fine.
So I'm inclined to think that something in the car is killing each alternator I put in there and I can't imagine how or what. Whatever it is, is probably what killed the first alternator at the beginning of all this.
I just wondered if anyone else had run into this problem.
This is getting very expensive not to mention just frustrating to do all that work over and over again.
So all my alternators seem to test good before I put them in the car and within one drive something kills them. The battery is new and fully charged.
Any ideas???
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #6 ·
Nathan, I forgot to ask. What is the rectifier plate? Or more properly where is the rectifier plate? I thought that was the same part as the regulator and brushes.
 

·
Registered
Joined
·
1,958 Posts
That's VERY strange. And I'd definitely be very frustrated at all of that swapping out. Also, when you take your alternator to be tested, most testers can not test the AMP output, only voltage, the voltage regulator, and the rectifier or diode plate. That's the black plate under the air snorkel, next to the voltage regulator. It converts the stator coils AC current to DC. Then it passes to the Voltage regulator to, regulate the voltage to no more than 14.5ish volts.



That green wire/white must be battery voltage when the ignition is on. It signals the rectifier plate to start working. Without that, your alternator is doing nothing.
 

·
Registered
Joined
·
1,958 Posts
Okay, so here's the pics and videos...

With the Green/White wire disconnected from the alternator, ignition off:


With the ignition on:


With the wire connected to the alternator, and the ignition off:


With the ignition On:


With the car running:


And now a video of the wire disconnected. Notice the Charge indicator light is not on when the ignition is on.


Now with the wire connected. Notice the light is now on when the ignition is switched on.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #10 ·
thanks Nathan.
Those are all very close to the readings I got and the indications I got with the same sets of conditions.
I truly appreciate all your effort and knowledge.
I must have something really wrong to keep blowing alternators. But I don't get any different test results than those you show. I have another car here and I get the same results with that one and it works fine. I know I've gotten bad parts before but what are the odds of half a dozen times in a row. I'm going to order another alternator, don't have any choice, and see what happens.
Man, I am completely frustrated!
Maybe I've been lucky, but I've never had an alternator go bad in all the Saabs I've owned. And I have a couple with over 300,000 miles on them.
I wonder if the starter could have anything at all to do with this?? It's the only other thing connected to the alternator. And even though I can't find anything wrong with it, I did have the charge test done on the car itself a week or so ago and the test did indicate that there was a problem with the starting system. I don't have any indications and the starter works just fine. I just figured it was a false reading caused by the fact that the alternator was not working.
 

·
Registered
Joined
·
1,958 Posts
No problem.

I don't see how the starter could kill an alternator if it's working properly. Once it disengages, there's really no way it can burn out anything. The charging and starting system is really simple. Even if your B+ cable from the alt to the starter to the battery was severely corroded, it wouldn't kill the alternator.

I too have never had an alternator give out on me till these 9-5's. All of the cars I've owned have all had a Bosch alternators. But there are several threads I've found with similar issues you're having. None were Saabs though.

Definitely let us know what you find when you resolve this problem.
 
1 - 11 of 11 Posts
Top