Battery light on. How to identify alternator model/brand?

[jac]

I think the alternator or the starter are going bad. I have ruled out the battery as I took the battery to the Batteries Plus and they confirmed it is still good.

I tried viewing the voltage through the cluster but I wasn't able to get to the option.

For now I am just trying to figure out what type of alternator I have to see what the cost of refurbishing it myself or replacing it could be. Is there a way to figure out the model/brand alternator without taking it out? I've had this car for 20 years now but I can't recall if this is the original alternator or not... Lol

Wondering if I should do the oil housing gasket too while I am in there.

[upallnight]

Most likely you have a Valeo alternator. You can get an inspection mirror and see if you can read the name.

[andrewwynn]

I switched mine from Valeo to Bosch when I replaced mine about two months ago. Turns out I could have probably just cleaned the brushes.

I refurbished wife's in the past year by just replacing brushes and swapping polarity of the slip rings (since only the one polarity takes 3/4 or more of the wear I didn't even bother changing the slip rings this time).

If you get some brushes and follow my thread how to swap the polarity you can probably get 60-100,000 more miles.

[jac]

Thanks gents. I did not get a chance to get the splash guard and all that other stuff out of the way so I did not get to use the mirror to check the brand, but thanks for the photo, now I know what to look for!

I was however able to get the cluster tests to work. With engine OFF, test #9 says 116, which I assume means 11.6volts. With the engine ON, test #9 says 111 (or 11.1v).

The battery was fully charged 2 weeks ago and the car had been sitting in the garage without me messing with it for 2 weeks and I can't believe it has discharged the battery that much just sitting there. :-)

Now that the test showed me the low voltage while running, I am going to assume that means that alternator is bad and so will spend some time tomorrow removing the alternator.

[Fifty150hs]

Originally Posted by jac

Thanks gents. I did not get a chance to get the splash guard and all that other stuff out of the way so I did not get to use the mirror to check the brand, but thanks for the photo, now I know what to look for!

I was however able to get the cluster tests to work. With engine OFF, test #9 says 116, which I assume means 11.6volts. With the engine ON, test #9 says 111 (or 11.1v).

The battery was fully charged 2 weeks ago and the car had been sitting in the garage without me messing with it for 2 weeks and I can't believe it has discharged the battery that much just sitting there. :-)

Now that the test showed me the low voltage while running, I am going to assume that means that alternator is bad and so will spend some time tomorrow removing the alternator.

If the alternator is only putting out 11.1 volts running I'm surprised it runs. I wouldn't trust a battery test in a auto parts store. I've taken batteries in that would not charge that my battery charger said were bad and they tested ok in the parts store. You definitely have a bad alternator. Put in a new one and put the battery on a charger for 24 hours. After charging for 24 hours put a voltmeter on it and see what the battery is holding. If it's not holding 12.3 volts it may be bad as well.

[Clavurion]

Originally Posted by jac

Now that the test showed me the low voltage while running, I am going to assume that means that alternator is bad and so will spend some time tomorrow removing the alternator.

Or just remove the voltage regulator is situ without removing the alternator. Then renew just the brushes (or the regulator with brushes).

[jac]

Originally Posted by Clavurion

Or just remove the voltage regulator is situ without removing the alternator. Then renew just the brushes (or the regulator with brushes).

That sounds like a lot less work! I am gonna try that for a little and see if I can figure out how to do that. Thanks!

[andrewwynn]

That is correct. Definitely alternator.

You’d have to have at least one extra joint in your fingers to remove the VR in place. I wanted to do that very badly.

Heres a tip though: the most difficult part is getting the bolts back in; grind the end into a cone.

I've redone mine and wife's and it was just brushes. I even replaced mine when it failed to find out the bushes only needed to be cleaned so now I have a spare alternator.

[Clavurion]

Originally Posted by andrewwynn

You’d have to have at least one extra joint in your fingers to remove the VR in place. I wanted to do that very badly.

Not sure on E53 but at least on E46 and E39 with M54 engine this can be done in situ. (Also done it on my E53 but with M57N engine.)

For example this video shows what you are looking for to remove the back cover and then change the brushes.

https://www.youtube.com/watch?v=aVvPzwtxdrM&t=25s

[oldskewel]

Originally Posted by Clavurion

Not sure on E53 but at least on E46 and E39 with M54 engine this can be done in situ. (Also done it on my E53 but with M57N engine.)

For example this video shows what you are looking for to remove the back cover and then change the brushes.

https://www.youtube.com/watch?v=aVvPzwtxdrM&t=25s

I watched that guy's great videos. Very interesting and impressive. I even bought the full rebuild kit (brushes, slip rings, bearings) from him on eBay. Ships from Ireland, so not good if you are in a rush. I think I did a quick VR swap when my alternator failed, and then bought his kit, and then when I had the engine apart later, it was convenient, so I did the rebuild.

Actually, looking through the video just now, I'll say that the back cover, etc. all look completely different vs. what mine does. Once you get deeper in there for the rebuild, everything he says applies, and the video is good. Apparently Valeo used the same brushes and slip rings on every alternator they made for about 3 decades (don't quote me on that, but I wish other manufacturers did not reinvent the wheel as much as they do).

And I won't doubt that *you* can do it in-situ, and if I really needed to do it to win a bet, I could probably do it too. But given a choice, and knowing what I know so far, I would remove the alternator.

On the tightness of the alternator when reinstalling, I've just cleaned up all the surfaces, and use anti-seize on a few key spots, and have never found it to be a big problem - e.g., no machining required. But I'll also say that probably due to being in California, I tend to have a lot less corrosion on everything vs. most of the photos I see of other engines.