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I bought a re-manufactured Bosch AL16X Alternator for my 76 Spider and had it installed by a professional Alfa shop. He removed my external voltage regulator and it set-up to run direct on the AL16X built-in regulator.

I have no heavy draw lights or stereo, it's a stock 76 Spider.

Had a bunch of work done at the same time, all new electricals; fuel pump, starter/solenoid and battery.

After 500 miles the alternator started making an intermittent terrible buzzing noise. It then failed so the shop replaced it with another, no extra cost.

Then 2 more months and 500 more miles then same problem, second unit bad.

I am now on the third AL16X and it made the same noise once yesterday and then again on start this morning. This is the third AL16X unit in 6 months to go wrong.

I even took out the AM/FM cassette and alarm, checked all the wiring and fuses.

Has anyone had a similar experience with these re-man units going bad so quickly?

I am tried of changing alternators, what other simple options do I have.

Thanks,
 

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Just out of curiosity, are you sure it is a Bosch brand, and not a local rebuilder selling the alternators using the Bosch reference number?

Since the shop replaced it FOC, I'm guessing they sold you the first one? If you didn't see the actual box it came in, it is quite likely they are using a non-Bosch part. I mention this because local rebuilders can be either outstanding...... or not. Bosch, while nothing unique, has historically be consistent in their quality.

If a true Bosch alternator fails three times, my guess is that there is a heavy current draw on it somehow, causing it to run very hot for extended periods. As the shop did a bunch of other work, I'd have them back-pedal through their efforts to find the cause. I would think they would be getting weary of tossing up free alternators by now.
 

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Yes, these are from a large local autopart retailer who also sell to mechanics. Nice looking, clean, new in Bosch boxes.

I did read on some other treads that there were concerns about Bosch rebuilt alternators, this is from the BMW R46Fanatics M forum dated (2-16-2010) : "My mechanic called BMW to get to the bottom of things & found out that their currently getting a 20% return rate on their Bosch alternators due to faulty rebuilding work."

The AL16X can't be used on too many vehicles now, I wonder if the part supply house had a bunch of these in stock from the previously reported bad rebuild problem times, I didn't check the date on the boxes.

Questions:

1) What would make the AL16X start buzzing like a chain saw?

2) What all could be causing a huge draw?

3) Could it be the built in voltage regulator is not sufficient?

4) Could the internal VR be disabled and the AL16X be wired to run through the Alfa external voltage regulator, I kept it just in case.

5) What other brand and model of alternator can I just bolt in my 76 Alfa Spider?

This had got me stumped and I don't feel comfortable driving any distance after spending thousands of dollars to restore a car that I have had for over 20 years.

It's really a shame, my car runs really well otherwise.

Thanks,
 

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Is the buzzing while the engine is running? It must be a loud buzzing to hear it over the engine. If it is buzzing while just sitting there, then I've never encountered that. Haven't encountered buzzing while running either. The only thing that might be called buzzing would be a bad bearing. I had the equivalent of an AL16 fail the front bearing within about 1000 miles of being rebuilt. The front bearing froze and started spinning in the case, then locked up, slung the belt, broke the fan, gored the radiator, and made a dent in the hood.

Anyone can have a bad run of rebuilt stuff, even Bosch. It is insanely rare to get three in a row, however. I would be looking at causes external to the alternator. A good shop should be able to measure the current load on the alternator with no difficulty. They should also be able to pin-out all of the voltages elsewhere and at least determine the direction to go hunting.

Good luck. A mystery, for sure.
 

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Is the buzzing while the engine is running? It must be a loud buzzing to hear it over the engine. If it is buzzing while just sitting there, then I've never encountered that. Haven't encountered buzzing while running either. The only thing that might be called buzzing would be a bad bearing. I had the equivalent of an AL16 fail the front bearing within about 1000 miles of being rebuilt. The front bearing froze and started spinning in the case, then locked up, slung the belt, broke the fan, gored the radiator, and made a dent in the hood.
Yes, an intermittent buzzing only when the engine is running and at higher RPM. Scarey loud buzzing along the lines of a chain saw but not as loud of course but definitely louder than my engine at 3500 RPM and traffic. At first I thought there was something in the fan or water pump bearing. The water pump. belts, hoses and rad are all new.

The alternator was the last item I replaced simply because it was 37 years old. I should have had it rebuilt instead of returning it for the $70 core.

This definitely sounds like bad bearings. I never thought of the alternator actually blowing up and damaging other things. That sounds like a lawsuit to me, did you get compensation for your damaged rad and hood?
 

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No compensation for me. The 1000 miles required longer than the warranty period, and when I called them about the low mileage I found that the company had been purchased and was now under a new name and ownership. No luck there.

BTW, I had a loud "buzzing" now that I think about it. I have a hunch it was a cracked fan blade, and this lead to its subsequent departure. Might take a very close look at the plastic on that blade.
 

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My old alternator made an awful noise intermittently before death. The regulator or maybe a diode or two messed up some how and (my theory) the alternator wanted to act like a brake and resist rotation by the engine. It would work for a while then, nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn, then be fine by the time I pulled over and opened the hood. After a couple days it stayed long enough to open hood and see/hear it was the alt.

You might be able to use your old reg. on your new alt. but you would need brushes and holder and some real shade tree wiring to make it go.
 

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Could the internal VR be disabled and the AL16X be wired to run through the Alfa external voltage regulator, I kept it just in case.
No, that wouldn't be possible. Plus I doubt the internal VR that is your issue - it's probably: incredibly poor-quality rebuilds, an excessive external load, or a wiring error in converting from external VR to internally-regulated.

I never thought of the alternator actually blowing up and damaging other things. That sounds like a lawsuit to me, did you get compensation for your damaged rad and hood?
I'm not a lawyer, but I'll bet if you spent $50,000 on legal fees, you could recover $500 toward a used hood and radiator.
 

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Post so I can private message

Hey, George Hess from Minnesota. You found my name on the GTV/ GT registry. It is true I am the owner of a 71 GTV #1532763 with a build date of 7/7/71. You are in the process of restoration project on #1532659 , build date of 7/10/71. My car does have its original engine? I would love to share the block number. I appreciate efforts of trying to make sense of Alfa engine numbers of the cars built at the same time or with close serial numbers.

That's good stuff,

Paul Henninge-the only one in the US so google will find you an email. please contact me that way.
 

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