Genuine BMW Alternator versus Aftermarket?

[bsprtsgrp]

Mine just went yesterday at 91K, battery light came on and vehicle went into TRANS FAIL SAFE MODE. Battery was measuring 11.8v running and 12.4v with engine off. Remans are Bosch, from BMW or not (mine is water-cooled)

[Peregrin-O]

Mine's still working good, although w/this freakin cold weather of -15F and below I cringe just before starting my car hoping it doesn't bust. Can't wait to move back to AZ.

I had no idea you can rebuild it.... Would you guys say that you're better off rebuilding it yourself or is it too time consuming and you're better off just buying a new one? What are your guys' opinion?

[JCL]

You can't really rebuild it yourself, you can repair it by replacing the regulator, etc.

Rebuilding is more complete.

Remanufacturing is more complete yet, and means returning it to new performance and condition levels.

Repair, Rebuild, and Reman are three different things, if done properly.

Being done properly is key. If you buy a spray paint rebuild that is sold as a reman, all bets are off.

[Peregrin-O]

Got it Thanks!

OP, I would say that aftermarket ones like Bosch brand would be good. I would look at the better warranty for each brand and if you can get a good deal on a new OEM then I would go with that. Even if its a reman or rebuild and if it has a good warranty it would be ok.

[JCL]

I wouldn't buy a rebuild. I would buy a reman unit with a warranty, probably from the dealer.

[bcredliner]

Have you been monitoring the alternator? How many miles since the warning lights?

Might want to stop by an auto parts store like Autozone and have them load test the battery and alternator--it's free.

[northfork]

Mine went at 132k and put me through "TRANS FAIL SAFE MODE" hell. Voltage would hit 17 and of course throw the error. Received good advise from a local mechanic "Take the BMW alternator off and have it rebuilt. Save the money (over a new part) and you still have the original BMW alternator." My cost....$65.00 and 18 months later still running fine.

[upallnight]

Originally Posted by northfork

Mine went at 132k and put me through "TRANS FAIL SAFE MODE" hell. Voltage would hit 17 and of course throw the error. Received good advise from a local mechanic "Take the BMW alternator off and have it rebuilt. Save the money (over a new part) and you still have the original BMW alternator." My cost....$65.00 and 18 months later still running fine.

[Ctsiegf]

No idea on the actual rate, but the alternator does seem to be a weaker point than most on the e53s.

Mine was replaced with a bosch aftermarket unit after it left me stranded at 85k miles. The cost was significantly less than an OEM unit. The warning lights came on once the day beforehand but it went away. The next day they came on for good and I had to make it the rest of the way to work on battery power only. That was exciting.

If I remember correctly, the bosch replacement was a 120A part instead of the stock 140A but that hasn't caused any problems.

Searching here at the time, there seemed to be a lot of threads on alternators failing. Like the radiator expansion tank, oil filter housing gasket or the ccv, it seems to be the price of poker for an e53.

-Carter

[X5only]

I buy my alternators from starterpros.com. These guys are the best in my book. For E53 4.4 N62 engine valeo goes for around $400 brand new or $200 remanufactured with LIFETIME no questions asked warranty. It's a no brainer. They can also rebuild your original for a fee. Ask for a quote if you want that option. But you'd have to first send it in.