Also, anyone have any experiences with the 1st gen x5M? Im considering selling my 4.8is soon and im on the fence. I would love to buy another X. Although my x5 has given me some problems, i dont think they are any worse than any other vehicle with 138k on the clock. The local BMW dealership replaced the head gaskets as well as the exhaust valve guidd sheilds under warranty. Total price for the job was 9k. It runs like silk now.

I fitted a VALEO one - don't remember if the OEM one was Valeo too - will check the old one if I won't forget ;)
But I had bought a new one, not a remanufactured one.

Can't find the Valeo part number, but I remember it wasn't marked as suitable for the e53 but fitted the other n62 cars like e60, e61,... So I thought I will give this one a try and it works like a charm, everything was identical to the old one. Only difference according to ETK the original one is 170A and my new one will deliver 180A. Older e53 4.4 n62 also had the 180A one: RealOEM.com - Online BMW Parts Catalog

Valeo Partnumbers I've found:
437529
TG17C027
TG17C027b

You are correct the reman. One is valeo and the oem
Part is valeo also.

I went through 2 reman'd units (O'reillys) in a month before breaking down and buying a brand new Valeo unit for ~$250 on ebay. No problems since then. They don't have very good quality control on the reman units from the parts stores.

Ok thats good as well as bad to hear. Its good becUse i was afraid there was a deeper issue with my electrical system causing the alternator to go bad quicker. But since it has a lifetime wArranty maybe ill see if i can just a refund since it keeps breaking and ill order a new oem unit.

According to the german Valeo homepage these steps are done during remanufactoring (short summary):

* dismantling and cleaning of all components
* new bearings
* electrical check of the rotor, painting; cleaning and painting of the stator
* checking and apinting of the pulley
* cleaning the regulator, brushes and springs will be replaced
* checking the diodes and they will be only replaced if need
* overall check after assembly

The problem might be the test of the diodes: they won't replace them if there was no fault during test, and if there was a fault they will replace the one which failed only...

Note: this information is just what they wrote on their homepage - doesn't mean this is the exact process!

Very true, also i noticed with the faulty units, they dont have an voltage surge problem always. Just under certain criteria. When outside temp is very hot or cool, heavy drivinr etc. modt of the time it functioned normally. So if they put it on a motor and spin the generator it wont have issue right away. Plus the work is done in mexico and the quality standards and training for the workers is sub par. The pay is minimal and the hours are wrong. Why would the workers even care if its done right?

Welcome to the world of rebuilt electrical components, third world working on first world devices, trained by no one, with no quality control measurements, much less any accountability.

Quality Control: "We don't need no stinking checker. If I say it's good, it's gets boxed and shipped!" ;):bustingup:bustingup:bustingup:bustingup:

They only bench test and replace hard failure components. No one is load testing anything.

The only way to test Alt out put is to load test to specific AMP value and read voltage,total amp output, and diode results. Reading volts will show regulator control/alt output but not total capacity and capabilities of the said unit. Testing must be done at 1500 RPM and again at 2500 RPM.

The cheapie rebuilt unit issues with poor/ inconsistent output are legendary all across the industry. If you are keeping the vehicle go with a new unit and save yourself a lots of grief.

check out the fuel pump, these will only squirt fuel for a short time if testing by removing a hose - as ECU shuts it off, I have one with a broken wire at the fuel pump which made intermittant contact

The X is fixed at this time. The alternator is the issue im dealing with now. The first one i replCed under warranty didnt even work. I had to take everything apart and do the job again. I was so angry