Stuffed Alternator - At a guess

**jayk** · 2nd February 2008, 09:57 AM

Hello All,

I have had varying symptons of the past year or so, which has finally eventuated in a stuffed alternator, I beleif. This is a 89 RR EFI. 3.5.

First Upon starting from cold, one of the belt would squeal for the first 30 secs, this would finally settle down.

Secondly, somtimes when I turned the headlights on I would loose my tacho. It would drop to zero and stay there. At this stage I didn;t think the 2 were related.

Thirdly, my alternator light on the dash was dimmly glowing when driving.

forthly, the alterntor light would glow bright when accelerating, but remian off at idle.

fifthly, the belt to the alternator would speal very loudly when accelerating, and during time of extreme loudness the tacho would drop to zero. Here if where I tidied symptom number 2 together, and did research and found the tacho was an output from the alt, I assumed it was from the coil, like everything else I have owned...

Sixly, I put a multimeter across the battery terminals, when idling it read in the region of 13.8. Which thought was ok. But bring the revs up and the volts come up with it. at about 2k revs. the volts climb to about 18v. This I didn't think was ok.

Finally, the alternator sounds pretty sick, and whines as it turns. Stick a srew driver to the alt and my ear and I can hear it grinding away.

Can any one see anything wrong with my assupmtions, and any one know if a decent (please suggest if so) auto elec can rebuild these things. It is a Magneti Marelli. I was told $645 for a replacement, and that they tend not to service them, as the shaft goes and cant be serviced..

Any suggestions experience or advice would be helpful

Rdgs,

JK.

**procrastination inc** · 2nd February 2008, 10:13 AM

I don't know these alternators well, but many have a regulator/rectifier/brush module screwed in to the back (little black box)

Sounds to me like the regulator component of this has broken down.

Maybe you could just replace the black box?

**dmdigital** · 2nd February 2008, 11:24 AM

Try Roverparts in Ballarat. I got one for my Tdi for about $300 posted to me.

**PhilipA** · 2nd February 2008, 03:09 PM

And you have been letting this go on for a year????
If it grinds the bearing is stuffed.
If it is showing 18V the regulator is stuffed, and it may blow up your battery.
You can get the parts from UK. they are very hard to get in Australia.
However most people replace the MM with a Bosch from a Magna.
Do a search, and there is a full description of how to do it.
Regards Philip A

**jayk** · 2nd February 2008, 07:55 PM

Hello,

No I haven't let this go on for a year. The light on the dash and the belt noise made me check the voltage at the battery. This is when I stopped driving it. These symptoms occurred the same day.

The tacho dropping to zero occasionally was happening rarely, and corrected if I turned the highlights off and then on again. I put it down to Lucifer Lucas. The might have happened 3 times in the last year.

I have ordered one from the UK. It hasn't arrived yet but it cost me $300 all up, including postage. Which is far less then the $645 I was quoted from buying here.

I wanted to know if these alternators can be re built. Is it viable, so it could be a spare. Having 2 rangies is excuse enough to have one spare on the shelf.

**PhilipA** · 2nd February 2008, 08:13 PM

I have purchased a diode pack and brush holder/regulator from the UK.(Paddocks) for a 65 Amp Magneto Marelli.
AFAIR it cost about $180 landed.
It is easy to solder the new diode pack in.

But they are generally considered by Auto electricians to be poor alternators. Mine lasted 80K.

So I now have a Bosch 85 Amp.
Regards Philip A

**jayk** · 3rd February 2008, 08:56 AM

Thanks PhillpA,

I will have a look at the Paddocks website...

**slug_burner** · 3rd February 2008, 09:38 AM

Look here this person did a service on their MM alternator, it is for a diesel but the alternator should be the same apart from the orentation of the case/brackets

Otherwise look here for a bosch swap

**MacMan** · 3rd February 2008, 08:03 PM

I really should update that page.

I have since done the cut and shut on the original bracket and it worked a treat. MUCH better than the adapter bracket that kept moving out of alignment.

Had a perfect run from the Bosch since then (just wish every other thing I own that has bearings in it would keep it's act together!!!) and I guess I have probably put another 10,000km.

I'd take pics of the arrangement now but I'm without a camera at present...

Cheers, Mike.

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