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Discussion Starter #1
I came back to my manual S4 today after a couple of months. It has been standing unused during that time.

I disconnect the battery when I leave it so I reconnected it and put it on charge overnight just to top it up.

I then started it (it started very easily) and drove it on to the lift to change the clutch fluid.

Having done that I took it for a drive and noticed the alternator light was on and voltage was showing as only 12v. This is something new for this car, normally the charging is fine and steady at 13.5v.

Part way through the drive the light went off and voltage came up to 13.5 before the same thing happened, the light came on and voltage fell back to 12v.

I wonder if I have:
1) Damaged the alternator diodes by charging with the battery connected. I always do this, though, and have not had a problem before.
Also, would the fact that it came back to life briefly suggest an intermittent fault like loose wire rather than fried components?.
2) Dislodged something while doing the clutch fluid. I checked the ground strap near the slave cylinder and that hasn't moved and is in good shape.
I have checked the wires from the alternator to the left fender and they havent changed - they are all tight.

Anything else I might have nudged,knocked or damaged?
 

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I'd lean toward #2. Unless you used an improperly connected jump starting charger it seems unlikely an overnight slow charge would damage the alternator. (I've done that many time with no problems.)

I'd check all the wires & connections. Even though they might look OK and feel tight, it can't hurt to remove each connection one-by-one to clean & secure them. (I use a toothbrush sized wire brush.) Also, I believe the alternator has to have a good ground connection through the case's connection to the block - might be worth making sure those surfaces are clean, too.

Having done all that, the next likely possibility is a bit of corrosion or sticking of the alternator's brushes. I think just driving it a bit would clean them off - might explain why it suddenly seemed to start working. IIRC, replacing the brush/regulator assembly is quite easy once you get access to the back end of the unit.
 

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Discussion Starter #3
Thanks Eric. Interesting point about the alternator brushes, I hadn't thought of that. I will give it a tap with a piece of wood or something when the engine is running.

I will have another good look at the various connections tomorrow and give them a clean then take it out for an Italian tune up.

I had a look at the wiring diagram just now. It looks as though the charge for the battery runs back along the heavy cable that feeds the starter motor. Given that the starter spins well I assume that this is OK.
 

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But Mad North-Northwest
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Charge for the battery goes back along that big line, but the voltage to the rest of the system goes on the thick red cable from the alternator to the junction box on the left side of the engine compartment. Check the connections there.

Clutch work may just be coincidence and your voltage regulator may be shot or brushes worn. As Eric said, it's pretty easy to replace.
 

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Clutch work may just be coincidence and your voltage regulator may be shot or brushes worn. As Eric said, it's pretty easy to replace.
I'm liking that theory - e.g., that it's just a coincidence that your alternator became intermittent after the clutch fluid replacement. The fact that the car has sat unused for several months is another clue - as ghnl wrote, something may have corroded over the winter.

How well does the battery hold a charge? It's also possible that several months of dis-use has killed the battery, leading to strange charging symptoms.

Removing and inspecting the brush/regulator assembly is easy. If the brushes look worn, replace. If they look good, the regulator is probably OK - not a lot to wear out in electronic regulators.
 

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Discussion Starter #6
Thanks for the suggestions.

I undid and cleaned the connections for the red and green wires from alternator to fender. They looked in good shape before I cleaned them and it made no difference. I will have access to a multimeter tomorrow so will test the voltage output at source.

If I have to take the alternator out it looks like I will have to take the left side fan out too, to give room to pull the alternator. Is that correct?
 

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Discussion Starter #7
Do these brushes look OK?

I answered my own question:)

Yes, the fan definitely needs to come out. Even then it was a struggle to get the alternator past the power steering pipes.

First off, it was filthy:frown2: A lot of oil around. So I gave it a good clean up, including inside and on the commutator rings.

I took the brushes out and gave them a clean too. They move in and out OK on their springs.
I have no experience of this so don't know if they are worn or not. They look to me as if they will be making contact OK but I would appreciate your opinions.
If I need new ones, anyone know the part number, it looks part worn off on this one?
 

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brushes look sort of OK to me (length of them anyway) but the whole thing looks very filthy.......when I took mine out the other day, they were pretty clean.....maybe oil leaking on your alt. from the bolt under the head, something like that??

anyway part no. is Bosch 1 197 311 028 (EL 14V 4C)

if you want to try and test it yourself, there is a video here, if you have the equipment!
 

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Discussion Starter #9 (Edited)
but the whole thing looks very filthy
You're not wrong there Dom, it was filthy all over. Definitely oil getting there from somewhere.
Thanks for the video and the part number. I will have a look at the video but don't have any test gear apart from a multimeter.
 

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Perhaps the accumulated oil inside the alternator is causing the intermittent charging problems.

Next step might be to remove the alternator, re-install the brush/regulator, and have the thing tested. Supposedly chain autoparts stores (e.g. Autozone, O'Reilly, ...) will do this gratis.

But if the alternator tests bad and you get a new one, it's only a matter of time until the oil leak will kill the new one too.
 

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Discussion Starter #11
I took the alternator to an old school auto electric place here in France today.
It looked the sort of place I would want to entrust my parts to as there was a superb E-Type Jaguar outside.
Inside was like a trip back twenty years. The guy put the alternator on his test bench, which had those BIG old dials, none of that fancy new LED/LCD stuff, ran it to speed and pronounced it dead.

So I have left it with him to dismantle and tell me how much it will cost to fix.

Separately, I need to sort the oil leak,as AlfaJay says. What are the likely places for it to drop onto the alternator?
There is oil in the spark plug well of no.1 so maybe the filler cap is still letting oil out (I thought I had fixed it)?

Or Dom mentioned a bolt under the head. Where is that exactly, I couldn't see it?
 

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But Mad North-Northwest
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Valve cover gasket, head gasket, or oil filter not tight enough are the first things that come to mind on that side of the engine.
 

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Discussion Starter #13
Thanks Tom. I will check those out. The oil was more on top of alternator than under it so I'm thinking less likely to be the filter but will give it a half turn anyway.

I found the bolt head that Dom mentioned and will take that out and seal it back in.

The filler cap is definitely suspect. It has oil across the width of the rubber seal so obviously isn't keeping it all where it should be.
 

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The filler cap is definitely suspect. It has oil across the width of the rubber seal so obviously isn't keeping it all where it should be.
Nick, the available Fiat seal ring for the cap (Fiat part # 7703051 ) are a lot better, and seal down really tight and snug...it is not flat, but has neat raised ribs on it to cause a great seal!

new on left, my effort (cut from some rubber stuff I had hanging around) on right

.....left is better, believe me:)

about 6 quid on ebay (# 271420271136 for example), if you look around it gets cheaper, maybe even your local (french) fiat dealer?
 

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Discussion Starter #16
Alternator now back in. The repair guy was very efficient and had it fixed early this morning.
So that works fine, a good healthy 13+ volts.
I took out that suspect bolt and it was oily, so I cleaned it up and put it back in with PTFE tape.
I will sort the filler cap and clean up around the head so I can where the oil is coming from.

For future reference, removing the fan wasn't the best route to take out the alternator. For the reinstall I took the air filter box out and that gave much better access.
 
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